Information for speakers about talk's duration:
30 min slot= 25 to speak + 5 for questions
18 min slot = 15 to speak + 3 for questions
A machine learning approach to the Galactic Center Excess
The search for dark matter (DM) weakly interacting massive particles with noble elements has probed masses down and below a GeV/c^2. The ultimate limit is represented by the experimental threshold on the energy transfer to the nuclear recoil. Currently, the experimental sensitivity has reached a threshold equivalent to a few ionization electrons. In these conditions, the contribution of a Bremsstrahlung photon or a so-called Migdal electron due to the sudden acceleration of a nucleus after a collision might be sizeable. We present a recent work where, using a Bayesian approach, we studied how these effects can be exploited in experiments based on liquid argon detectors. In particular we develop a simulated experiment to show how the Migdal electron and the Bremsstrahlung photon allow to push the experimental sensitivity down to masses of 0.1 GeV/c^2, extending the search region for dark matter particles of previous results. For these masses we estimate the effect of the Earth shielding that, for strongly interacting dark matter, makes any detector blind. Finally, given the relevance of the Migdal electrons to the search for low mass DM, we discuss some new ideas on how to possibly measure such an effect with detectors based on a Time Projection Chamber exposed to an high neutron flux.
The CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) experiment, installed at the Laboratori Nazionali del Gran Sasso (LNGS), is suited for direct detection of dark matter particles via elastic scattering off nuclei of CaWO$_{4}$.
CRESST uses an array of crystals (24 g each) operated as cryogenic calorimeters, each equipped with a cryogenic light detector.
An interaction in the CaWO$_{4}$ crystal produces a phonon and light signal: the phonon signal allows a precise energy measurement, the light signal is used to discriminate the expected dark matter signal (nuclear recoil) from the dominant background (electron/gamma and alpha). In early 2018, CRESST completed an initial data taking campaign reaching nuclear recoil thresholds of 30.1 eV. This unprecedented low threshold allows to probe dark matter particle masses below 500 MeV/$c^{2}$ and down to 160 MeV/$c^{2}$.
Most recent results are presented and discussed. The perspective for the next phase of the experiment will be also discussed.
The axion was originally proposed to explain the small size of CP violation in quantum chromodynamics. The axion would have a small mass and be weakly coupled to nucleons. If sufficiently abundant, it might be a candidate for the dark matter in the universe. Axions or axion-like particles (ALPs), when coupled to gluons, induce an oscillating Electric Dipole Moment (EDM) along the nucleon's spin direction. This can be used in an experiment to search for axions or ALPs using polarized charged particles in a storage ring.
In the spring of 2019, at the Cooler Synchrotron (COSY) in Jülich, we performed a first test experiment to search for ALPs using an in-plane polarized deuteron beam with a momentum of 0.97 GeV/$c$. The field of the ring magnets precesses the deuteron polarization in the horizontal plane relative to the beam velocity at a rate determined by the deuteron anomalous magnetic moment multiplied by the relativistic factor $\gamma$. In the frame of the moving beam, the radial electric field due to the ring magnets ($\mathbf{v}\times \mathbf{B}$) rotates the EDM. If the spin precession frequency equals the EDM oscillation frequency, which is proportional to the ALP mass, a resonance occurs that accumulates the rotation of the polarization out of the ring plane. This rotation is detected with a polarimeter that measures the transverse components of the beam polarization while the beam is stored. Since the axion frequency is unknown, the momentum of the beam was slowly ramped, thus changing $\gamma$, to search for a vertical polarization jump that would occur when the resonance is crossed. At COSY, four beam bunches with different polarization directions were used to make sure that no resonance was missed because of the unknown relative phase between the polarization precession and the EDM oscillations. We scanned a frequency window of about a 1 kHz width around the spin precession frequency of 121 kHz. This talk will describe the experiment and show preliminary results.
Neutron stars harbour matter under extreme conditions, providing a unique testing ground for fundamental interactions.
Dark matter can be captured by neutron stars via scattering, where kinetic energy is transferred to the star.
This can have a number of observational consequences, such as theheating of old neutron stars to infra-red temperatures.
Previous treatments of the capture process have employed various approximation or simplifications.
We present here an improved treatment of dark matter capture, valid for a wide dark matter mass range, that correctly incorporates all relevant physical effects.
These include gravitational focusing, a fully relativistic scattering treatment, Pauli blocking, neutron star opacity and multi-scattering effects.
We provide general expressions that enable the exact capture rate to be calculated numerically, and derive simplified expressions that are valid for particular interaction types or mass regimes and that greatly increase the computational efficiency.
Our formalism is applicable to the scattering of dark matter from any neutron star constituents, or to the capture of dark matter in other compact objects.
We apply these results to scattering of dark matter from neutrons, protons, leptonic targets, as well as exotic Baryons.
For leptonic Targets, a relativistic description is essential. Regarding Baryons, we outline two important effects that are missing from most evaluations of the dark matter capture rate in neutron stars.
As dark matter scattering with nucleons in the star involves large momentum transfer, nucleon structure must be taken into account via a momentum dependence of the hadronic form factors.
In addition, due to the high density of neutron star matter, we should account for nucleon interactions rather than modeling the nucleons as an ideal Fermi gas.
Properly incorporating these effects is found to suppress the dark matter capture rate by up to three orders of magnitude.
We find that the potential neutron star sensitivity to DM-lepton scattering cross sections greatly exceeds electron-recoil experiments, particularly in the sub-GeV regime, with a sensitivity to sub-MeV DM well beyond the reach of future terrestrial experiments.
We present preliminary results for DM-Baryons scatterings in Neutron stars, were the sensitivity is expected to greatly exceed current DD experiments for the spin-dependent case in the whole masse range, and for spin-independent in the low and high mass range.
Regarding White Dwarfs, for dark matter-nucleon scattering, we find that white dwarfs can probe the sub-GeV mass range inaccessible to direct detection searches, with the low mass reach limited only by evaporation, and can be competitive with direct detection in the 1 − 104 GeV range.
White dwarf limits on dark matter-electron scattering are found to outperform current electron recoil experiments over the full mass range considered, and extend well beyond the ∼ 10 GeV mass regime where the sensitivity of electron recoil experiments is reduced.
Unusual masses of black holes being discovered by gravitational wave experiments pose fundamental questions about the origin of these black holes. Black holes with masses smaller than the Chandrasekhar limit $\approx$ 1.4 M$_\odot$ are essentially impossible to produce through stellar evolution. We propose a new channel for production of low mass black holes: stellar objects catastrophically accrete nonannihilating dark matter, and the small dark core subsequently collapses, eating up the host star and transmuting it into a black hole. The wide range of allowed dark matter masses allows a smaller effective Chandrasekhar limit and thus smaller mass black holes. We point out several avenues to test our proposal, focusing on the redshift dependence of the merger rate. We show that redshift dependence of the merger rate can be used as a probe of the transmuted origin of low mass black holes.
Sterile neutrino is a simple and elegant dark matter candidate. In its minimal incarnation, the original Dodelson-Widrow mechanism that explains the relic abundance has been in strong tension with the indirect detection limits. I present the self interacting neutrino scenario, mediated by a Majoron-like scalar or vector boson, as a novel solution to the above tension. It can accommodate new production mechanisms for sterile neutrino dark matter, open up a wide parameter space, and result in a number of testable signatures from the laboratorie s to the cosmos.
LUX-ZEPLIN (LZ) is a direct detection dark matter experiment located at the Sanford Underground Research Facility in Lead, South Dakota. The experiment consists of three nested detectors; a dual phase xenon TPC, an actively instrumented liquid xenon skin, and an outer detector neutron veto formed by 10 acrylic tanks of gadolinium-loaded liquid scintillator. The active region of the xenon TPC contains 7 tonnes of liquid xenon with a 5.6 tonne fiducial volume, allowing us to reach a WIMP-nucleon spin-independent cross section sensitivity of 1.4 x 10$^{-48}$ cm$^{2}$ for a 40 GeV/c$^{2}$ mass in 1000 live days. In this talk I will give an overview of the LZ experiment currently being commissioned, and report on its status.
Antinuclei in cosmic rays are considered a unique probe for signals from exotic physics, such as WIMP Dark Matter annihilations. Indeed, these channels are characterised by a very low astrophysical background, which comes from antinuclei produced by high energy cosmic ray interactions with ordinary matter.
In order to make quantitative predictions for antinuclei fluxes near earth, both the production and annihilation cross sections of antinuclei need to be accurately known down to low energies.
In ultra relativistic pp, p-Pb and Pb-Pb collisions at the CERN LHC, matter and antimatter are abundantly produced in almost equal amounts, allowing us to study the production of antinuclei and measure their absorption in the detector material. The antinuclei absorption cross section is evaluated on the average ALICE material. Using this result, we then predict the transparency of our galaxy to anti-3He from both dark matter annihilations and high energy cosmic ray collisions.
In this talk we present the first measurements of the antideuteron and anti-3He absorption cross section with ALICE and we discuss the implications of these results for indirect Dark Matter searches using cosmic antinuclei.
Anomalies and opportunities in indirect searches for Dark Matter
TBA
Information for speakers about talk's duration:
30 min slot= 25 to speak + 5 for questions
20 min slot = 15 to speak + 5 for questions
With the end of RUN-II, the LHC has delivered only 4% of the collision data expected to be available during its lifetime. The next data-taking campaign -- RUN-III -- will double the integrated luminosity the LHC accumulated in 10 years of operation. The Run-III will be the herald of the HL-LHC era, an era when 90% of total LHC integrated luminosity (4 ab-1) will be accumulated allowing ATLAS to perform several precision measurements to constrain the Standard Model Theory (SM) in yet unexplored phase-spaces and in particular in the Higgs sector, only accessible at LHC. Direct searches have so far provided no indication of new physics beyond the Standard Model, however, they can be complemented by indirect searches that allow extending the reach at higher scales. Indirect searches are based on the ability to perform very precise measurements, a highly complex task at a hadron collider that will require tight control of theoretical predictions, reconstruction techniques, and detector operation. Moreover, populating extreme regions of phase-space for multi-differential production cross-section analysis will require the development and validation of Monte Carlo phase-space biasing techniques and efficient integration methods to produce the billions of events needed to cope with higher luminosities.
To answer the quest for high precision measurements in a high luminosity environment, a comprehensive upgrade of the detector and associated systems was devised and planned to be carried out in two phases. The Phase-I upgrade program foresees new features for the muon detector, for the electromagnetic calorimeter trigger system, and for all trigger and data acquisition chain and will operate to accumulate about 350 fb-1 of integrated luminosity during the RUN-III. The RUN-III will mark the debut of a new trigger system designed to cope with more than 80 simultaneous collisions per bunch crossing. After this, ATLAS will proceed with the Phase-II upgrade to prepare for the high luminosity frontier where the ATLAS experiment will face more than 200 simultaneous collisions per bunch crossing and a high radiation level for many subsystems. The Phase-II upgrade comprises a completely new all-silicon tracker with extended rapidity coverage that will replace the current inner tracker detector; the calorimeters and muon systems will have their trigger and data acquisition systems fully redesigned, allowing the implementation of a free-running readout system. Finally, a new subsystem called High Granularity Timing Detector will aid the track-vertex association in the forward region by incorporating timing information into the reconstructed tracks. A final ingredient, relevant to almost all measurements, is a precise determination of the delivered luminosity with systematic uncertainties below the percent level. This challenging task will be achieved by collecting the information from several detector systems using different and complementary techniques.
The presentation will describe physics goals and the status of the ongoing detector upgrades for RUN-III and the HL-LHC era.
This abstract is being submitted by the ATLAS Upgrade Speaker Committee representative. If approved, the speaker will be selected from ATLAS Collaboration and the conference will be informed.
To maximize the physics reach, the LHC plans to increase its instantaneous luminosity to $7.5\times 10^{34}$ cm$^{-2}$ s$^{-1}$, delivering from 3 to 4 ab$^{-1}$ of data at $\sqrt{s}=$14 TeV. In order to cope with this operation condition, the ATLAS detector will require new sets of both front-end and back-end electronics. A new trigger and DAQ system will also be implemented with a single-level hardware trigger featuring a maximum rate of 1 MHz and 10 μs latency. Enhanced software algorithms will further process and select events, storing them at a rate of 10 kHz for offline analysis. The large number of detector channels, huge volumes of input and output data, short time available to process and transmit data, harsh radiation environment and the need of low power consumption all impose great challenges on the design and operation of electronic systems. This talk will focus on these challenges, the proposed solutions and the latest results obtained from the prototypes.
This abstract is being submitted by the ATLAS Upgrade Speaker Committee representative. If approved, the speaker will be selected from ATLAS Collaboration and the conference will be informed.
The Tile Calorimeter (TileCal) is a sampling hadronic calorimeter covering the central region of the ATLAS experiment. TileCal uses steel as absorber and plastic scintillators as active medium. The scintillators are read-out by the wavelength shifting fibres coupled to the photomultiplier tubes (PMTs). The analogue signals from the PMTs are amplified, shaped, digitized by sampling the signal every 25 ns and stored on detector until a trigger decision is received. The TileCal front-end electronics reads out the signals produced by about 10000 channels measuring energies ranging from about 30 MeV to about 2 TeV. Each stage of the signal production from scintillation light to the signal reconstruction is monitored and calibrated to better than 1% using radioactive source, laser and charge injection systems. The performance of the calorimeter has been measured and monitored using calibration data, cosmic ray muons and the large sample of proton-proton collisions acquired in 2009-2018 during LHC Run-1 and Run-2.
The High-Luminosity phase of LHC, delivering five times the LHC nominal instantaneous luminosity, is expected to begin in 2028. TileCal will require new electronics to meet the requirements of a 1 MHz trigger, higher ambient radiation, and to ensure better performance under high pile-up conditions. Both the on- and off-detector TileCal electronics will be replaced during the shutdown of 2025-2027. PMT signals from every TileCal cell will be digitized and sent directly to the back-end electronics, where the signals are reconstructed, stored, and sent to the first level of trigger at a rate of 40 MHz. This will provide better precision of the calorimeter signals used by the trigger system and will allow the development of more complex trigger algorithms. Changes to the electronics will also contribute to the data integrity and reliability of the system. New electronics prototypes were tested in laboratories as well as in beam tests.
Results of the calorimeter calibration and performance during LHC Run-2 are summarized, the main features and beam test results obtained with the new front-end electronics are also presented.
The Liquid Argon Calorimeters are employed by ATLAS for all electromagnetic calorimetry in the pseudo-rapidity region |η| < 3.2, and for hadronic and forward calorimetry in the region from |η| = 1.5 to |η| = 4.9. It also provides inputs to the first level of the ATLAS trigger. After successful period of data taking during the LHC Run-2 between 2015 and 2018 the ATLAS detector entered into the a long period of shutdown. In 2022 the LHC should restart and the Run-3 period should see an increase of luminosity and pile-up up to 80 interaction per bunch crossing.
To cope with this harsher conditions, a new trigger readout path have been installed on the during the long shutdown. This new path should improve significantly the triggering performances on electromagnetic objects. This will be achieved by increasing by a factor of ten, the number of available units of readout at the trigger level.
The installation of this new trigger readout chain required the update of the legacy system to cope with the new components. It is more than 1500 boards of the precision readout that have been extracted from the ATLAS pit, refurbished and re-installed. The legacy analogic trigger readout that will remain during the LHC Run-3 as a backup of the new digital trigger system has also been updated.
For the new system it is 124 new on-detector boards that have been added. Those boards are able to digitize the calorimeter signal for every collisions i.e. at 40MHz and in radiative environment. The digital signal is then processed online to provide the measured energy value for each unit of readout an for each bunch crossing. In total this is up to 31Tbps that are analyzed by the processing system and more than 62Tbps that are generated for downstream reconstruction. To minimize the triggering latency the processing system had to be installed underground. There the limited space available imposed the needs of a very compact hardware structure. To achieve a good enough compacity larges FPGAs with high throughput have been mounted on ATCA mezzanines cards. In total no more than 3 ATCA shelves are used to process the signal of approximately 40k channels.
Given that modern technologies have been used compared to the previous system, all the monitoring and control infrastructure had to be adapted and commissioned as well.
This contribution should present the challenges of such installation, what have been achieved so far and what are the milestones still to be done toward the full operation of both the legacy and the new readout paths for the LHC Run-3.
DarkSide run since mid-2015 a 50-kg-active-mass dual-phase Liquid Argon Time Projection Chamber (TPC), filled with low radioactivity argon from an underground source and produced world-class results for both the low mass (M_WIMP<20 GeV/c^2) and high mass (M_WIMP>100 GeV/c^2) direct detection search for dark matter.
The next stage of the DarkSide program will be a new generation experiment involving a global collaboration from all the current Argon based experiments. DarkSide-20k is designed as a 20-tonne fiducial mass dual-phase Liquid Argon TPC with SiPM based cryogenic photosensors and is expected to be free of any instrumental background for exposure of >100 tonne x year. Like its predecessor, DarkSide-20k will be housed at the INFN Gran Sasso (LNGS) underground laboratory, and it is expected to attain a WIMP-nucleon cross-section exclusion sensitivity of 7.4 x 10^{-48} cm^2 for a WIMP mass of 1 TeV/c^2 in a 200 t yr run. DarkSide-20k will be installed inside a membrane cryostat containing more than 700 t of liquid Argon and be surrounded by an active neutron veto based on a Gd-loaded acrylic shell. The talk will give the latest updates of the ongoing R&D and prototype tests validating the initial design.
A subsequent objective, towards the end of the next decade, will be the construction of the ultimate detector, ARGO, with a 300 t fiducial mass to push the sensitivity to the neutrino floor region for high mass WIMPs.
In a noble gas time projection chamber, the electrons produced in the ionization are drifted to the anode for position reconstruction of the event, while the ions move in the opposite direction. The drift velocity of ions in liquid argon is five orders of magnitude slower than electrons, and a positive volume region is created by the accumulated ions, known as space charge. We studied the effects of the space charge for the next generation of liquid argon multi-tonne experiments for neutrino physics and dark matter searches
The space charge can modify the drift lines, the amplitude of the electric field, and ultimately the velocity of the electrons, thus, a displacement in the reconstructed position of the ionization signal can be produced. The constant recombination between free ions and electrons can produce a quenching of the charge signal and a constant emission of photons, uncorrelated in time and space to the physical interactions. In dual-phase detectors with charge amplification, where the electrons are extracted to the gas phase and multiplied, these effects can be worsened by the ion feedback from gas to liquid phase.
In this talk, the predictions of the space charge effects for multi-ton argon detectors, with drift lengths of several meters, are presented, evidencing some potential concerns for this kind of detectors particularly when operated on surface. Finally, recent experimental results regarding the direct measurement of the ion feedback from the gas into the liquid phase, obtained with a dedicated setup in our laboratory, will also be discussed.
The LUXE experiment aims at studying high-field QED in electron-laser and photon-laser interactions, with the 16.5 GeV electron beam of the European XFEL and a laser beam with power of up to 350 TW. The experiment will measure the spectra of electrons and photons in non-linear Compton scattering where production rates in excess of $10^9$ are expected per 1 Hz bunch crossing. At the same time positrons from pair creation in either the two-step trident process or the Breit-Wheeler process will be measured, where the expected rates range from $10^{-3}$ to $10^3$ per bunch crossing, depending on the laser power and focus. These measurements have to be performed in the presence of low-energy high radiation-background. To meet these challenges, for high-rate electron and photon fluxes, the experiment will use Cherenkov radiation detectors, scintillator screens, sapphire sensors as well as lead-glass monitors for backscattering off the beam-dump. A four-layer silicon-pixel tracker and a compact electromagnetic tungsten calorimeter with GaAs sensors will be used to measure the positron spectra. The layout of the experiment and the expected performance under the harsh radiation conditions will be presented.
Mu2e aims to measure the ratio of the rate of the neutrino-less muon to electron coherent conversion in the field of an aluminum nucleus relative to the rate of ordinary muon capture. In order to do that, Mu2e will exploit a detector system composed of a straw tracker and an electromagnetic calorimeter. The latter has to provide precise information on energy (σE/E <10%), time (σt < 500ps) and position (σx < 1cm) for ∼100 MeV electrons. It is composed of 1348 un-doped CsI crystals, each coupled to two large area Silicon Photomultipliers (SiPMs). Each SiPM is connected to a Front End Electronics (FEE) chip, which hosts the shaping amplifier and the high voltage linear regulator. Each group of 20 FEE is controlled by one Mezzanine Board (MB), which passes the amplified signals to the Digitizer ReAdout Controller board (DiRAC). The DiRAC samples the waveforms at 200 MHz with 12-bits ADCs, packs the data according to the Mu2e custom format and transmits them to the event builder through an optical transceiver. In order to limit the number of pass-through connectors and the length of the cables, the readout and digitization electronics will be located inside the detector cryostat, close to the interaction target. The boards are expected to sustain a neutron fluence of about 5x1010 n/cm2 @ 1 MeVeq (Si)/y and a Total Ionizing Dose of about 12 krad, while working into a 1T magnetic field and a vacuum of 10-4 Torr. This harsh operational environment has made the electronics design challenging, requiring an extended campaign of tests to select and qualify the employed electronic components. Moreover, to validate the performances of the system in terms of dynamic, SNR, bandwidth, and linearity, we assembled a full system chain (20 FEE board, one MB and one DiRAC prototype) to read the Module-0 (a medium scale prototype of the calorimeter) during a cosmic rays test. We demonstrated that the readout electronics performs satisfactorily: the signal shape is as expected from the Monte Carlo simulation, with an obtained time resolution of about 350 ps for MIP particles. In this paper we report on the board architecture and design, on the qualification of the prototypes and on the performance tests, as well as on the results of the first vertical slice test of the Mu2e calorimeter.
The STAR Collaboration is building a Forward Upgrade to supplement the excellent mid-rapidity capabilities of the STAR Detector for the final years of the RHIC program. The Forward Upgrade will utilize tracking and electromagnetic and hadronic calorimetry to trigger on and measure charged and neutral hadrons, photons, jets, and di-electrons over the pseudorapidity region 2.5 < η < 4. The Forward Upgrade will enable critical measurements to test the limits of universality and factorization in QCD when combined with future data from the EIC. In pp collisions, it will probe the structure of the nucleon at very high and low x, including for example measurements of the Sivers and Collins effects at x values higher than have been studied in semi-inclusive DIS. In p+Au collisions, it will probe nuclear modifications of the gluon density at low x and explore non-linear dynamics characteristic of the onset of gluon saturation. In Au+Au collisions, it will probe the longitudinal dynamics of hot QCD matter. This talk will present the status of the Forward Upgrade construction and describe the physics program that it will enable.
The Compact Muon Solenoid (CMS) detector at the CERN Large Hadron Collider (LHC) is undergoing an extensive Phase II upgrade program to prepare for the challenging conditions of the High-Luminosity LHC (HL-LHC). A new timing detector in CMS will measure minimum ionizing particles (MIPs) with a time resolution of 30-40 ps for MIP signals at a rate of 2.5 Mhit/s per channel at the beginning of HL-LHC operation. The precision time information from this MIP Timing Detector (MTD) will reduce the effects of the high levels of pileup expected at the HL-LHC, bringing new capabilities to the CMS detector. The barrel timing layer (BTL) of the MTD will use sensors that are based on LYSO:Ce scintillation crystals coupled to SiPMs with TOFHIR ASICs for the front-end readout. In this talk we will present motivations for precision timing at the HL-LHC and an overview of the MTD BTL design, including ongoing R&D studies targeting enhanced timing performance and radiation tolerance.
The MIP Timing Detector (MTD) of the Compact Muon Solenoid (CMS) will provide precision timestamps with 40 ps resolution for all charged particles up to a pseudo-rapidity of |η|=3. This upgrade will mitigate the effects of pile-up expected under the High-Luminosity LHC running conditions and bring new and unique capabilities to the CMS detector. The endcap region of the MTD, called the Endcap Timing Layer (ETL), will be instrumented with silicon low gain avalanche detectors (LGADs), covering the high-radiation pseudo-rapidity region 1.6 < |η| < 3.0. The LGADs will be read out with the ETROC readout chip, which is being designed for precision timing measurements. We present recent progress in the characterization of LGAD sensors for the ETL and development of ETROC, including test beam and bench measurements.
The aim of the Phase-2 Upgrade of LHCb is to collect up to 300 fb$^{-1}$ of data in a few years, operating at a luminosity of $(1..2)\cdot10^{34} cm^{-2}s^{-1}$. Because of the significant increase in particle densities and radiation doses, the present LHCb Electromagnetic Calorimeter (ECAL) will require a major revision. The increased instantaneous and integrated luminosity will result in very high particle density and radiation doses in the areas close to the beam pipe. In these conditions, ECAL has to provide high-quality energy and position measurement for electromagnetic showers, as well as separation of two closely lying showers. Another requirement for the whole ECAL, which is aimed to reduce combinatorial background at high luminosity operation, is the ability to measure the time of arrival of the photon or electron with an accuracy of few tens of picosecond. The intrinsic time resolution of the ECAL modules is expected to be sufficient to meet this requirement, although the use of an additional timing layer is not excluded. The expected particle flow and radiation doses strongly depend on the distance from the beam pipe and determine the technology and granularity of the upgraded ECAL modules. The upgraded ECAL will be subdivided accordingly into several zones. The central part, with the highest expected doses, will be a sampling spaghetti calorimeter (SPACAL) based on radiation-hard crystal scintillators and a Tungsten absorber. The peripheral areas will be instrumented with modified Shashlik type modules, similar to the modules of the present ECAL, with modifications aiming to achieve the best time resolution for this technology. The intermediate part will be a spaghetti calorimeter with polystyrene-based scintillating fibres and a moulded lead absorber. The main advantages of using lead-polystyrene spaghetti type are the possibility to modify granularity with minimal intervention and fibres replacement to increase radiation hardness. An extensive R&D campaign is ongoing to optimize the Upgrade 2 ECAL structure. It includes: - studies of scintillating materials, in terms of scintillation kinetics and radiation hardness; - simulation studies to find the optimal detector layout, longitudinal segmentation and granularity; - beam test studies of the performance of various ECAL module prototypes, both for central (SPACAL) and peripheral areas. for the moment, a time resolution for 5 GeV electrons achieved for W-Crystal and Lead-Polystyrene Spacal prototypes is about 20 ps, and better than 40 ps for Shashlik type modules. In this talk, we will present the results of time resolution measurements for all these technologies, as well as predictions from detailed Monte-Carlo simulation.
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30 min slot= 25 to speak + 5 for questions
25 min slot= 20 to speak + 5 for questions
Experimental prospects for BSM searches at the LHC.
The discovery of the Higgs boson with the mass of 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable to solely explain some observations. Many extensions of the Standard Model addressing such shortcomings introduce additional Higgs-like bosons which can be either neutral, singly-charged or even doubly-charged. Precision measurements of the coupling of the Standard Model Higgs boson can also be used to place constraints on two-Higgs-doublet models. Constraints on the couplings of The current status of searches based on the full LHC Run 2 dataset of the ATLAS and CMS experiments at 13 TeV are presented.
The direct production of electroweak SUSY particles, including sleptons, charginos, and neutralinos, is a particularly interesting area of search at the LHC. While the lightest neutralino is a well motivated and studied candidate for dark matter in models with R-parity conservation, the small production cross sections of electroweak production leads to difficult searches. This talk will highlight the most recent results of searches performed by the ATLAS and CMS experiments for supersymmetric particles produced via electroweak processes, including analyses with leptonic and hadronic final states.
The most recent results of searches for supersymmetric (SUSY) particles produced via strong interaction, as well as for SUSY particles of the third generation, will be presented. The analyses are performed by the ATLAS and CMS Collaborations and are based on the full data set of proton-proton collisions collected during the Run 2 of the LHC.
Although the LHC experiments have searched for and excluded many proposed new particles up to masses close to 1 TeV, there are many scenarios that are difficult to address at a hadron collider. This talk will review a number of these scenarios and present the expectations for searches at an electron-positron collider such as the International Linear Collider. The cases discussed include the light Higgsino, the stau lepton in the coannihilation region relevant to dark matter, and heavy vector bosons coupling to the s-channel in e+e- annihilation. The studies are based on the ILD concept at the ILC.
The International Linear Collider offers a number of unique opportunities for searches for dark matter and dark sector particles. The collider program will offer important capabilities, but also, the ILC will enable new fixed-target experiments using the high-energy electron and positron beams, both beam dump experiments and dedicated experiments using single beams. This talk will describe the expectations for these programs, which address all of the possible dark sector portals.?
(on behalf of the ILC International Development Team Speakers Bureau)
The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. The ATLAS and CMS experiments have developed a broad search program for DM candidates, including resonance searches for the mediator which would couple DM to the SM, searches with large missing transverse momentum produced in association with other particles (light and heavy quarks, photons, Z and H bosons) called mono-X searches and searches where the Higgs boson provides a portal to Dark Matter, leading to invisible Higgs decays. The results of recent searches on 13 TeV pp collision data, their interplay and interpretation will be presented.
We constrain the Higgs-portal model employing the vector-boson fusion channel at the LHC. In particular, we include the phenomenologically interesting parameter region near the Higgs resonance, where the Higgs-boson mass is close to the threshold for dark-matter production and a running-width prescription has to be employed for the Higgs-boson propagator. Limits for the Higgs-portal coupling as a function of the dark-matter mass are derived from the CMS search for invisible Higgs-boson decays in vector-boson fusion at 13 TeV. Furthermore, we perform projections for the 14 TeV HL-LHC and the 27 TeV HE-LHC taking into account a realistic estimate of the systematic uncertainties. The respective upper limits on the invisible branching ratio of the Higgs boson reach a level of 2 % and constrain perturbative Higgs-portal couplings up to dark-matter masses of about 110 GeV.
[This talk is a combination of several submitted abstracts, including the following.]
In the recent years, several measurements of $B$-decays with flavor changing neutral currents, i.e. $b\to s$ transitions hint at deviations from the Standard Model (SM) predictions. These decays are forbidden at tree-level in the SM and can only proceed via suppressed loop level or box diagrams. Rare decays of $B$ mesons are an ideal probe to search for phenomena beyond the SM, since contributions from new particles can affect the decays on the same level as SM particles.
The Belle II experiment is a substantial upgrade of the Belle detector and operates at the SuperKEKB energy-asymmetric $e^+ e^-$ collider. Radiative $b\to s \gamma$ decays is already been observed and inclusive photon spectra is also obtained with only a small dataset of Belle II. Early measurements related to the electro-weak penguin $b\to s \ell\ell$ and $b\to s \nu\bar\nu$ decays has also been performed. We will discuss the results obtained with the current dataset along with the prospects for the searches of these radiative and electroweak penguin decays with the expected $50~ab^{-1}$ full dataset of Belle II.
In the Standard Model (SM), the $b \to s$ and $b \to d$ flavor-changing neutral currents (FCNC) are induced by loop effects. Rare semileptonic $B$-meson decays originated by these currents are standard channels for testing the SM precisely and searching for possible physics beyond the Standard Model. Differential branching fractions of semileptonic $B$-decays and angular distributions in some of them are experimentally measured by the LHCb, ATLAS and CMS collaborations at the LHC as well as by BaBar and Belle at the $B$-factories. We also anticipate significantly improved results from the ongoing Belle-II experiment.
Here, we consider the rare $B^\pm \to \pi^\pm \ell^+ \ell^-$ decay, where $\ell = e, \mu, \tau$ is a charged lepton, and present its dilepton invariant-mass spectrum and decay rate based on the effective electroweak Hamiltonian approach for the $b \to d \ell^+ \ell^-$ transitions in the SM, taking into account also the weak annihilation diagrams. We present theoretical predictions for total and partial branching fractions for $B^+ \to \pi^+ \tau^+ \tau^-$ in dependence on the parameterization type for the $B \to \pi$ form factors. Our prediction for the total branching fraction of $B^+ \to \pi^+ \mu^+ \mu^-$ agrees with the LHCb result (Aaij R. et al.,LHCb Collab., JHEP 10 (2015) 34) within the experimental and theoretical uncertainties. Moreover, accounting for the weak annihilation contributions allows us to obtain a better agreement with the experimental data on the distribution in the dimuon invariant mass squared $q^2$ in the entire kinematically allowed region and, in particular, in its lowest $q^2$-part. The importance of the long-distance contributions from the light vector mesons on the dilepton invariant-mass spectrum is also discussed. These results are potentially useful in testing the lepton flavor universality in the FCNC $B \to \pi \ell^+ \ell^-$ decays.
BESIII has collected 2.9 and 6.3 fb-1 of e+e- collision data samples at 3.773 and 4.178-4.226 GeV, respectively. We report recent measurements of the (semi)leptonic decays D(s) -> l+nu (l=mu, tau) and D(s) -> X l+nu [X=K(*), rho, eta('), a_0, K_1, and l=e, mu]. The decay constants f_D(s), the semileptonic form factors f(0) and the CKM matrix elements |V_cs(d)| are determined precisely. These results are important to verify the LQCD calculations of f_D(s) and f(0) and the CKM matrix unitarity. Precision tests of lepton-flavor universality with (semi)leptonic D decays are also made.
Recent years have seen a series of anomalies hinting at lepton universality violation in B-meson decays, which can be explained with a single TeV-scale Pati-Salam leptoquark mediator found in "4321" models. The tension of the muon (g-2) measurement, as recently confirmed at Fermilab, with SM prediction can, however, not be explained with the same mediator. We explore how to explain the muon (g-2) in a "4321" model and find that such a model naturally addresses the fermion mass hierarchies.
The ATLAS and CMS experiments have performed measurements of B-meson rare decays proceeding via suppressed electroweak flavour changing neutral currents.
This talk will focus on the latest results from the ATLAS and CMS on B^0_s → mu mu, B^0 → mu mu, B^0 → K^0 mu mu and B^+ → K^()+ mu mu decays. The LHC combined results on the B decays to two muons will also be presented.
In this talk, we will present the status of lepton flavor physics in composite Higgs models with partial compositeness in the light of recent data in the lepton sector. We will consider anarchic flavor setups, scenarios with flavor symmetries, and minimal incarnations of the see-saw mechanism that naturally predict non-negligible lepton compositeness.
The focus will be on lepton flavor violating processes, dipole moments, and on probes of lepton flavor universality, all providing stringent tests of partial compositeness. We discuss the expected size of effects in the different approaches to lepton flavor and the corresponding constraints, including ‘UV complete’, effective and holographic descriptions.
Flavour physics with rare, electroweak-penguin, and semileptonic decays at LHCb
Many new physics scenarios contain ultralight scalars, states which are either exactly massless or much lighter than any other massive particle in the model. Axions and majorons constitute well-motivated examples of this type of particle. In this work, we explore the phenomenology of these states in low-energy leptonic observables. After adopting a model independent approach that includes both scalar and pseudoscalar interactions, we briefly discuss the current limits on the diagonal couplings to charged leptons and consider processes in which the ultralight scalar $\phi$ is directly produced, such as $\mu \rightarrow e \phi$, or acts as a mediator, as in $\tau \rightarrow \mu \mu \mu$. Contributions to the charged leptons magnetic and electric moments are studied as well.
CKM, CPV and mixing results at LHCb
Four-quark operators mediate non-leptonic kaon decays and play an important role in inclusive QCD observables. Using their symmetry transformations and the known properties of QCD at low energies, we re-derive and extend generic relations among matrix elements and study their phenomenological implications. They include a determination of the electroweak-penguin contributions to eps'/eps based on hadronic tau-decay data and a study of the interplay of those relations with recent lattice data, which can be used to test the accuracy of large-Nc based estimates of matrix elements and to improve the predictive power in the tau sector.
The recent CPV measurements from ATLAS and CMS with B0s to J/psi Phi decays will be discussed together with some recent results concerning Heavy Flavour production from both experiments.
Information for speakers about talk's duration:
20 min slot = 15 to speak + 5 for questions
Due to the high production of light mesons J/ψ radiative and hadronic decays, the largest sample of J/ψ events accumulated at the BESIII detector offers a unique laboratory to study the light mesons spectroscopy and search for the light exotic states. In this talk, we shall report the recent progresses on the light meson spectroscopy achieved at BESIII.
The $\pi^-p\to\pi^-\eta p$ and $\pi^- p\to\pi^-\eta^\prime p$ reactions were recently studied by the COMPASS collaboration at CERN. The analysis has shown that for high energies the $\pi\eta^{(')}$ system is produced in two kinematic regimes. In these regimes the laboratory frame direction of $\eta^{(')}$ is either forward or backward. The Gottfried-Jackson frame analysis of the polar angle distribution revealed the characteristic forward-backward asymmetry in the polar angle, with the asymmetry being stronger for the $\pi\eta^\prime$ system. We describe these processes in terms of double Regge exchange, where both meson-meson and meson-baryon invariant masses are large. The multi-Regge processes had been extensively studied in the seventies and the elegant mathematical formulation of the production amplitudes was developed. Nevertheless, the phenomenological status of the multi Regge approach was still not clear even in the simplest case of three particles in the final state. We have shown that applying the double Regge exchange and taking into account the leading $2^{++}$ Regge trajectories, we are able to explain the forward-backward asymmetry. We have also identified the dominant amplitudes and indicated that the observed asymmetry originates from the interference of the even and odd partial waves (with the latter being exotic). Especially the impact of the strongest odd wave, namely the $P-$ wave, is interesting through its direct relation to the production of the putative $\pi_1$ hybrid meson. The high energy amplitudes can be formally related to the production of exotic resonances through the Finite Energy Sum Rules.
KLOE and KLOE-2 experiment, operated at the DA$\Phi$NE facility of Frascati, acquired almost 8 fb$^{-1}$ of data at the $\phi$ peak resonance.
The two samples together represent the largest statistics ever collected at an $e^+ e^-$ collider at 1.02 GeV center-of-mass energy.
With about 2.4 $\times 10^{10} \,\phi$ and $3.1 \times 10^8 \,\eta$ meson events available for data analysis, KLOE-2 can give an important contribution to hadron spectroscopy and Dark Force research fields. Moreover, thanks to the installation in both DA$\Phi$NE arms of two tagger station, KLOE-2 can also investigate the $\gamma\gamma$ fusion.
The $\eta \to \pi^0 \gamma \gamma$ decay is considered a ChPT golden mode because of its sensitivity to the $p^6$ term on both the branching ratio (BR) and the M($\gamma\gamma$) spectrum. There is a 4.5 $\sigma$ discrepancy between the KLOE preliminary BR measurement, obtained with 450 pb$^{-1}$, and the most accurate one from Crystal Ball.
By increasing sample statistics KLOE-2 can confirm or solve this discrepancy.
We are also active in the dark force field by testing an alternative model where the Dark Force mediator is an hypothetical leptophobic B boson that can couple only to barions with same quantum numbers of the $\omega$ meson. For masses less than 600 MeV the expected dominant decay channel is into $\pi^0\gamma$, thus we are investigated this possibility in the $\phi \to \eta B\to \eta \pi^0\gamma$ channel with $\eta \to \gamma \gamma$.
KLOE-2 aims to precisely measure the $\pi^0$ decay width into $\gamma \gamma$ by profiting of the $\pi^0$ production through $\gamma\gamma$ fusion. The status of the $\gamma^{\ast}\gamma^{\ast}\to \pi^0$ analysis will be reported.
We want also to precisely measure the $\omega$ cross section in the $e^+ e^- \to \pi^+ \pi^- \pi^0 \gamma_{\rm ISR}$ channel using the Initial State Radiation (ISR) method. Promising results on this item will be also presented.
KLOE-2 searched for the P and CP violating decay $\eta\rightarrow\pi^+\pi^-$ by exploiting the radiative $\phi\rightarrow\eta\gamma$ process with 1.6~fb$^{-1}$ of KLOE data.
No signal is observed in the $\pi^+\pi^-$ invariant mass spectrum and a limit on the branching ratio at 90\% CL has been extracted.
The limit results to be B($\eta\rightarrow\pi^+\pi^-$)$< 4.9 \times 10^{−6}$, three times lower than previous KLOE one,
the combination of the two KLOE limits gives a B($\eta\rightarrow\pi^+\pi^-$)$< 4.4 \times 10^{−6}$.
Moreover, KLOE-2 perform the search for the double suppressed $\phi\rightarrow \eta\, \pi^+ \pi^- $ and the conversion
$\phi\rightarrow \eta\, \mu^+ \mu^- $ decays with both $\eta \to \gamma \gamma$ and $\eta \to 3\pi^0$. Clear signal are observed for the first time.
I will present the recent studies by the Joint Physics Analysis Center on the tools to extract information about the excited hadron spectrum from data.
The large data sample accumulated by the Belle experiment at the KEKB asymmetric-energy e^{+} e^{-} collider provides a unique opportunity to perform studies related to hadron spectroscopy utilising various production mechanisms. We studied the two-photon process \gamma\gamma \to \gamma\psi(2S) is studied for the first time and found an evidence for a structure in the \gamma\psi(2S) invariant-mass distribution at 3921.3 \pm 2.4 \pm 1.6\,{\rm MeV}. We report the first measurement of exclusive cross sections for $e^{+}e^{-} \to B\bar{B}$, $e^{+}e^{-} \to B\bar{B}^{*}$, and $e^{+}e^{-} \to B^{*}\bar{B}^{*}$ in the energy range from $10.63$ to $11.02\,{\rm GeV}$. In addition, we report a search for the $\chi_{bJ}(nP)$ bottomonium states at Belle. Other studies on conventional or exotic charmoniuum and bottomoniuum are also presented.
We study several chiral Lagrangians that describe the two- and three-body decays of a pseudoscalar glueball, $J^{P C} = 0^{−+}$, with a mass of $2.6$ GeV and its first excited state with a mass of $3.7$ GeV. Their masses were predicted by lattice QCD simulations. We compute the decay of the pseudoscalar glueball into (pseudo)scalar and (axial-)vector mesons as well as their excited states. We calculate also the decay of the first excited state into light mesons, charmonia, excited states, and into a scalar and pseudoscalar glueball. These states and channels are in reach of the ongoing BESIII, Belle II, LHCb, and NICA experiments and the upcoming PANDA experiment at the FAIR facility. The various branching ratios are parameters-free predictions.
In e+e- collisions between 2 and 3 GeV, excited states of rho, omega and phi can be produced directly. Especially the resonances around 2GeV like rho(2000), rho(2150) and \phi(2170) are not fully understood yet. Theorists describe the phi(2170) as a traditional s s-bar state, an s s-bar g hybrid, a tetraquark state, a Lambda Lambda-bar bound state, or a phi KK resonance. The predicted decay widths vary strongly depending on the assumed nature of phi(2170). With energy scan data collected by the BESIII collaboration between 2.0 GeV and 3.08 GeV, the properties of phi(2170) are studied systematically in PWAs of its expected decay modes, such as e+e- -> K+K-pi0pi0, phi eta', phi eta, K+K-, and eta' pi+pi-.
We extend previous work concerning rest-frame partial-wave mixing in Hamiltonian effective field theory to both elongated and moving systems, where two particles are in a periodic elongated cube or have nonzero total momentum, respectively. We also consider the combination of the two systems when directions of the elongation and the moving momentum are aligned. This extension should also be applicable in any Hamiltonian formalism. As a demonstration, we analyze lattice QCD results for the spectrum of an isospin-2 ππ scattering system and determine the s, d, and g partial-wave scattering information. The inclusion of lattice simulation results from moving frames significantly improves the uncertainty in the scattering information.
The GlueX experiment conducts searches for hybrid mesons, using a linearly polarized photon beam, impinging on a liquid hydrogen target. The GlueX detector provides a close to $4\pi$ acceptance and allows to reconstruct both, neutral and charged particle tracks which are produced in the $\gamma p$ reactions.
GlueX is taking data in two phases and has collected $\sim8.4\,\rm{PB}$ of raw data so far. The first phase data has been fully reconstructed and calibrated, whereas the second phase is still running, using a DIRC upgrade.
This talk will give a brief overview of the GlueX physics program, highlighting the latest results obtained from the phase one data analysis. This includes the determination of polarization observables, cross section measurements, as well as an outlook on the first steps towards an amplitude analysis of hybrid meson search channels.
The world’s largest sample of J/ψ 1.3 billion events accumulated at the BESIII dector offers a unique opportunity to study light meson decays. In recent years the BESIII experiment has made significant progresses in eta/eta' decays, including observation of eta'->pi+pi- mu+mu-, search for the rare decays of eta’->4pi0 and eta’->gam gam eta as well as the search for CP violation in eta’->pi+pi- e+e-. In addition, the prospects for the light meson decays with the available 10 billion J/ψ will also be discussed.
The hadron spectrum is tangled with threshold and triangle singularities
that difficult the identification of actual resonance states.
We present a thermal-field theory computation in the late hadron stage
of the fireball. Our finding is that such singularities can be filtered
by comparing other data to heavy ion collisions:
peaks therein seem more likely to be hadrons than rescattering effects when
two (easily checkable) conditions are met.
First, the flight-time of the intermediate hadron state in the triangle
must be comparable to the lifetime of the equilibrated fireball
(else, the reaction is delayed until after freeze out, proceeding as in vacuo).
Second, the loop-particle mass or width must be sizeably affected by the medium.
When these conditions are met, the singularity can be vastly reduced:
at T about 150 MeV, even by two orders of magnitude, dropping out of the spectrum.
Based on European Physical Journal C 81, 430 (2021)
Information for speakers about talk's duration:
25 min slot= 20 to speak + 5 for questions
20 min slot = 17 to speak + 3 for questions
The hypertriton (3ΛH) is the lightest hypernucleus consisting of a proton, a neutron, and a Λ hyperon. From old emulsion experiments, the Λ separation energy of the hypertriton has been measured as 130 ± 50 keV. Theoretical calculation shows that Λ hyperon is separated by ~10 fm from the deuteron inside hypertriton. Therefore, as a very loosely bound system, the lifetime of the hypertriton has been estimated to be close to that of free Λ particle (τ = 263 ps). However, in recent years, the lifetime of hypertriton in heavy-ion based experiments (ALICE, STAR and HypHI) has been found to be 30-40% shorter than expectation. This has been recognized as the hypertriton lifetime puzzle. In heavy-ion based experiments, the hypertriton events have been identified using invariant mass and the lifetime of hypertriton is derived from decay length. In order to shed light on this puzzling issue, we propose to measure the hypertriton lifetime in time domain directly as an independent and complementary approach.
Our proposal has been approved as the E73 experiment at J-PARC in Japan. The E73 experiment employs the (K-, pi0) reaction to populate hypertriton. This reaction is a novel production method to convert a proton into Λ hyperon by detecting pi0 meson. The high energy gamma-ray (>500 MeV) decayed from the forward projectile pi0 is used to select Λ events with smaller recoiling momentum, which has higher formation probability for hypertriton. These high energy gamma-ray are detected by the calorimeter installed in the downstream of the beamline. Hypertriton events can be identified with mono-energic pi- at ~114 MeV/c from two-body mesonic weak decay, which is measured by Cylindrical Detector System (CDS) composed of a solenoid magnet, a drift chamber and timing counters. The lifetime of hypertriton can then be derived from the time difference between start counter and stop counter after subtracting TOF obtained from tracking. The advantage of this approach is that it allows us to carry out a direct lifetime measurement, which is different from the heavy-ion based experiments. Another merit of the E73 experiment is to selectively populate hypertriton ground state and avoid any contribution from the postulated 3/2 excited state.
We have performed a test experiment with 4He target to demonstrate the feasibility of (K-, pi0) reaction in June 2020.The pilot run with 3He target has been carried out in May 2021. We have successfully identified 4ΛH and 3ΛH events. For case of 4ΛH, our new method allows us to drastically improve the precision of 4ΛH lifetime. For the just completed experiment with 3He target, we will derive the production cross section as a reference for the final data taking run planed in 2022~2023. In this talk, we will describe the details of our experimental method and present the current status of the E73 experiment.
The femtoscopic studies done by the ALICE Collaboration provided results with unprecedented precision for the short-range strong interactions between different hadron pairs. The next challenge is the development of the three-particle femtoscopy which will deliver the first ever direct measurement of genuine three-body forces. Such results would be a crucial input for the low-energy QCD and neutron star studies. In particular, the momentum correlation of p-p-p triplets can provide information about genuine three-nucleon forces while the p-p-$\Lambda$ interaction is a necessary piece to understand if the production of $\Lambda$ hyperons occurs in neutron stars. In this talk, the first study of femtoscopic p-p-p and p-p-$\Lambda$ correlations will be presented. The results were obtained using high-multiplicity pp collisions at $\sqrt{s}$ = 13 TeV measured by ALICE at the LHC. The measured three-body correlation functions include both three- and two-particle interactions. The cumulant method was applied to subtract lower order contributions and infer directly on the genuine three-body forces. The two-particle contributions were estimated both experimentally by applying mixed-event technique, and mathematically by projecting known two body correlation functions on the three-body systems. The measured p-p-p and p-p-$\Lambda$ correlation functions and the corresponding cumulants will be shown.
The $^{3}_{\Lambda}\text{H}$ is a bound state of proton (p), neutron (n) and $\Lambda$. Studying its characteristics provides insights about the strong interaction between the lambda and ordinary nucleons. In particular, the $^{3}_{\Lambda}\text{H}$ is an extremely loosely bound object, with a large wave-function.
As a consequence, the measured (anti-)$^{3}_{\Lambda}\text{H}$ production yields in pp and p-Pb collisions are extremely sensitive to the nucleosynthesis models.
Thanks to the very large set of pp, p-Pb and Pb-Pb collisions collected during Run 2 of the LHC the ALICE collaboration has performed systematic studies on the $^{3}_{\Lambda}\text{H}$ lifetime, binding energy and production across different collision systems.
The new ALICE results on hypertriton properties have a precision which is comparable with the current world averages and they can be used to constrain the state-of-the-art calculations which describe the $^{3}_{\Lambda}\text{H}$ internal structure.
Furthermore, with the precision of the presented production measurements some configurations of the Statistical Hadronisation and Coalescence models can be excluded leading to tighter constraints to available theoretical models.
The hypertriton puzzle concerns the connection between lifetime and binding energy of the simplest yet worst understood hypernucleus consisting of one proton, neutron and Lambda.
A new experiment is prepared at the Mainz Microtron facility to determine the hypertriton Lambda binding energy via decay pion spectroscopy, which was successfully pioneered in the recent years. The experiment makes use of a novel high luminosity lithium target which at the same time minimizes the momentum smearing. Together with a precise beam energy determination via the undulator light interference method a recalibration of the magnetic spectrometers will be done to achieve the goal of a statistical and systematic error of about 20 keV.
This project is supported by the Deutsche Forschungsgemeinschaft, Grant Number PO256/7-1 and the European Union’s Horizon 2020 research and innovation programme No. 824093. For the A1 Collaboration.
The study of the antikaon nucleon system at very low energies plays a key role for the understanding of the strong interaction between hadrons in the strangeness sector. The information provided by the low energy kaon- nucleon interaction is accessible through the study of kaonic atoms. The lightest atomic systems, namely the kaonic hydrogen and the kaonic deuterium, provide the isospin dependent kaon-nucleon scattering lengths by measuring the X-rays emitted during their de-excitation to the 1s level. Until now, the most precise kaonic hydrogen measurement and an exploratory measurement of kaonic deuterium were carried out at the DAFNE collider by the SIDDHARTA collaboration, combining the excellent quality kaon beam delivered by the collider with new experimental techniques, as fast and very precise X-ray detectors, like the Silicon Drift Detectors. Today, the most important experimental information missing in the field of the low-energy antikaon-nucleon interactions is the experimental determination of the hadronic energy shift and width of kaonic deuterium, and will be measured by the new SIDDHARTA-2 experiment, which is installed in DAFNE and is ready to start the data taking campaign. The experimental challenge of the kaonic deuterium measurement is the very small x-rays yield, the even larger width (compared to kaonic hydrogen) and the difficulty to perform x-rays spectroscopy with weak signals in the high radiation environment of DAFNE. It is therefore crucial to develop a new large area X-rays detector system to optimize the signal and to control and improve the signal-to-background ratio by gaining in solid angle, increasing the timing capability and as well implementing an additional charge particle tracking veto systems. In the talk I shall review the kaonic atoms measurements performed by SIDDHARTA, the status and plans of SIDDHARTA-2 and future perspectives to measure other kaonic atom systems at the DAFNE collider.
In the course of its full lifetime $\overline{\mbox{P}}$ANDA at FAIR will address the physics of strange baryons with S=-2 in nuclei by several novel and unique measurements. This series of experiments will start with the exclusive production of hyperon-antihyperon pairs close to their production threshold in antiproton-nucleus collisions. This day-one experiment offers a hitherto unexplored opportunity to elucidate the behaviour of antihyperons in nuclei.Within its intermediate stage $\overline{\mbox{P}}$ANDA will offer the unique possibility to search for X-rays from very heavy hyperatoms as e.g. $\Xi^-$-$^{208}$Pb. This will complement experiments at J-PARC which attempt to measure X-rays in medium-heavy nuclei. Finally, $\overline{\mbox{P}}$ANDA will extend the studies on double $\Lambda$ hypernuclei by performing high resolution $\gamma$-spectroscopy of these nuclei for the first time.
This contribution will focus on the hyperatom experiment in all of its facets. Besides its dedicated detector components, the talk will present simulation studies for the expected event rates and how they influence the achievable precision in the estimation of the $\Xi^-$-nuclear potential. Since this estimation is strongly correlated with the shape of the nuclear periphery of the $^{208}$Pb nucleus, the systematic uncertainty inherited by the neutron skin thickness of $^{208}$Pb is also discussed.
This project has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 824093.
The attractive nature of $\bar{K}N$ interaction has stimulated theoretical and experimental searches for $K^-$ bound states in different systems. In particular, many theoretical calculations devoted to the lightest possible system $\bar{K}NN$ have been performed using different methods: Faddeev equations with coupled channels, variational methods, and some others, see a review [1] and references therein. All of them agree that a quasi-bound state in the $K^- pp$ system exists but they yield quite diverse binding energies and widths. The experimental situation is unsettled as well: several candidates for the $K^- pp$ state were reported by different experiments, but the measured binding energies and decay widths of such state differ from each other and are far from all theoretical predictions.
Detection of the heavier four-body $\bar{K}NNN$ system could be easier than in the case of $\bar{K}NN$ since direct scattering of $K^-$ on three-body nuclei can be performed. Some theoretical works were devoted to the question of the quasi-bound state in the $\bar{K}NNN$ system with different quantum numbers, but more accurate calculations within Faddeev-type equations are needed. The reason is that only these dynamically exact equations written in momentum representation can treat energy dependent $\bar{K}N$ potentials, necessary for the this system, exactly.
We are solving four-body Faddeev equations in AGS form [2] in order to search for
the quasi-bound state in the $\bar{K}NNN$ system. We are using our experience with the three-body AGS calculations, described in [1], and our two-body potentials, constructed for them. Namely, three models of the $\bar{K}N$ interaction are being used: two phenomenological potentials and a chirally motivated one. All three potentials describe low-energy $K^- p$ scattering and $1s$ level shift of kaonic hydrogen with equally high accuracy. This will allow us to study the dependence of the four-body results on the two-body input.
[1] N.V. Shevchenko, Few Body Syst. 58, 6 (2017).
[2] P. Grassberger, W. Sandhas, Nucl. Phys. B 2, 181 (1967).
The electromagnetic structure of baryons is modified in the nuclear medium.
The modifications can be inferred from the comparison between the electromagnetic form factors in medium with the respective form factor in vacuum.
Of particular interest is the ratio between the electric and magnetic form factors in medium ($G_E^*/G_M^*$) and vacuum ($G_E/G_M$) of octet baryons.
The deviation of the double ratios ($G_E^*/G_M^*)/(G_E/G_M)$ from unity measures the impact of the medium modification of the electromagnetic structure in a nuclear medium.
Measurements of the double ratios $(G_E^*/G_M^*)/(G_E/G_M)$ may become available in a near future using the transfer polarization method developed at Jefferson Lab.
We present estimates of the double ratios of octet baryons for different nuclear densities based on a constituent quark model which take into account meson cloud excitations of the baryon cores.
Our results show different features, namely, enhancement or quenching depending on the octet baryon flavor content.
[1] G. Ramalho, J.P.B.C. de Melo, K. Tsushima, Phys.Rev. D100, 014030 (2019).
[2] G. Ramalho, K. Tsushima, A.W. Thomas, J. Phys. G40, 015102 (2013).
In the figure, we present our estimates for the double ratios of the proton and neutron for different nuclear densities.
The relative production rate of (multi-)strange hadrons in high-multiplicity hadronic interactions is enhanced with respect to the one measured at lower multiplicities and reaches values observed in heavy-ion collisions. The microscopic origin of this striking phenomenon, originally interpreted as a signature of Quark-Gluon Plasma (QGP) formation, is still unknown: is it related to soft particle production or to hard scattering events, such as jets? Is it related to final particle multiplicity only or does it also depend on initial-state effects? The ALICE experiment has addressed these questions by performing dedicated measurements in pp collisions at $\sqrt{s}=13$ TeV.
To separate strange hadrons produced in jets from those produced in soft processes, the angular correlation between high-${p_{\mathrm{T}}}$ charged particles and strange hadrons has been exploited. The near-side jet yield and the out-of-jet yield of $\mathrm{K^0_S}$ and $\Xi$ have been studied as a function of the multiplicity of charged particles produced in pp collisions.
Moreover, a multi-differential analysis has been exploited to disentangle the contribution of final-state multiplicity from the one of effective energy available for strange particle production. The effective energy has been estimated by subtracting the energy measured in the Zero Degree Calorimeters (ZDC) from the centre-of-mass collision energy.
The results suggest that soft (i.e. out-of-jet) processes are the dominant contribution to strange particle production and that initial-state properties do not play a significant role in strangeness production, which is mainly driven by final particle multiplicity.
The High Acceptance DiElectron Spectrometer (HADES) is a fixed target experiment which explores the properties of hadronic matter in collisions of pions, protons and nuclei at beam energies 1-2 AGeV. It operates at the SIS18 accelerator in GSI, Darmstadt.
The precise measurements of neutral mesons yield were already carried out by TAPS collaboration. However, their measurements have only one bin in rapidity. Due to the newly built electromagnetic calorimeter ECal, the HADES experiment has the unique possibility to study the dependence of π0 yield on rapidity (in the range 0.8-1.8) and transverse momentum (200-900 MeV/c).
In this talk the preliminary results of measurements of yield of π0-mesons by the HADES experiment in collisions of Ag+Ag nuclei at beam energy 1.23 AGeV are discussed.
Knowledge of whether the proton's electromagnetic (EM) structure changes when it is bound inside an atomic nucleus is important for a better understanding of nuclear matter and its behavior. If such change is present it is expected to be relatively small and therefore difficult to experimentally determine.
The ratio of the transverse to longitudinal polarization-transfer components in the $\mathrm{A}(\vec{e},e'\vec{p})$ reaction is proportional to the proton electromagnetic form factor (FF) ratio $G_E/G_M$. Experiments searching for in-medium modification of EM FF ratio were carried out on protons from different nuclei ($^2\mathrm{H}$, $^4\mathrm{He}$, $^{12}\mathrm{C}$, and $^{16}\mathrm{O}$). Although the observed polarization transfer ratios deviated significantly (especially for those with higher Fermi momenta) from those of free proton, these differences could be accounted for with the inclusion of different nuclear effects. We observed that deviations in the measured polarization ratios from those of free-proton scattering have a similar dependence on virtuality (a measure of off-shellness) in all measured nuclei.
In our last experiment, instead of comparing results between different nuclei or comparing them against a free-proton scattering, we evaluated polarization transfer to protons extracted from $s$ and $p$ shell of $^{12}\mathrm{C}$ nucleus and examined the differences. This was motivated by theoretical predictions that local nuclear densities experienced by protons in these two shells differ approximately by a factor of two, which could lead to significant changes in the proton EM FF ratio. Comparing protons from the same nucleus has also the advantage of reducing the influence of various experimental uncertainties. We will present these new data and the results in form of individual polarization components as well as their ratios that we obtained both as a function of the missing momentum (related to proton Fermi momentum) and proton's virtuality.
Jets emerging from heavy-flavour quark fragmentation represent convenient benchmark probes for perturbative quantum chromodynamics and heavy-flavour fragmentation models. In contrast to light-flavour jets, heavy-flavour jet substructure should be affected by the dead cone effect which suppresses collinear gluon emission off a heavy-flavour quark radiator. This phenomenon may affect also cold nuclear matter effects and in-medium energy loss of heavy-flavour jets in heavy-ion collisions.
The ALICE experiment at the LHC exploits its excellent particle tracking capabilities, which allow for a precise jet reconstruction and identification of heavy-flavour hadron decay vertices, displaced hundreds of micrometers from the primary interaction vertex. In the talk, we will report on heavy- flavour jet measurements done in pp and p-Pb collisions by ALICE. While the presented pp results will focus on discussion of the dead cone effect and D jet substructure measurements, the new b-jet results will be used to constrain cold nuclear matter effects in p-Pb down to jet transverse momentum 10 GeV/c. Finally we will discuss also the new fragmentation distribution measurement done with reclustered subjets.
Ultra-relativistic heavy-ion collisions have unlocked the study of a hot, dense state of QCD matter, the Quark-Gluon Plasma (QGP). However, due to its short lifetime, on the yoctosecond scale, the QGP must be studied with recourse to external probes, such as jets, collimated sprays of particles originated from the hard scattering.
Since jets are multi-scale probes, we can use jet quenching, the collection of medium modifications of the jets’ substructure, to study the evolution of medium properties at various times
In this work, we show that one can assign a time structure to jets by using the formation time of a parton’s emission. The obtained clustering history can be accurately reconstructed, and the medium modifications can be studied at various timescales, potentiating future tomographic measurements of the QGP.
Further, by classifying jets according to the formation time of the first unclustering step, one can select, out of an inclusive measurement, jet populations that were strongly modified by the QGP. This selection of jet populations by their quenching magnitude can help to distinguish specific features of jet-QGP interaction.
Interactions of high-$p_{\rm{T}}$ partons with quark-gluon plasma (QGP) result in jet quenching, which is manifest by the suppression of high-$p_{\rm{T}}$ jet yields and the modification of jet substructure and di-jet acoplanarity distributions. Several jet quenching phenomena can be measured precisely over a wide range of jet $p_{\rm{T}}$ using semi-inclusive distributions of charged jets recoiling from a high-$p_{\rm{T}}$ trigger hadron, which incorporate data-driven suppression of the large uncorrelated background produced in heavy-ion collisions.
In this talk we report semi-inclusive measurements of hadron-jet acoplanarity in Pb-Pb collisions at $\sqrt{s_{\rm{NN}}} = 5.02$ TeV and high-particle multiplicity pp collisions at $\sqrt{s} = 13$ TeV. In the Pb-Pb system, where QGP formation is established, narrowing of the acoplanarity is observed relative to a reference distribution from pp collisions. In contrast, pp events with high-particle multiplicity exhibit a broadening of the acoplanarity relative minimum bias events. In this case, however, qualitatively similar features are also seen in pp collisions generated by the PYTHIA 8, which does not include jet quenching or other QGP effects. We will discuss the current status of these analyses, and prospects to understand the origin of these striking phenomena.
Over the last decades, analytical calculations of jet quenching observables were force to always make a distinction between jet evolution in dense or dilute mediums. Although there are different theoretical formalisms suited for each one of these scenarios, taking into account multiple soft and single hard interactions between the probe and the background under a single approach has proven to be a difficult task. In this talk, I will introduce the Improved Opacity Expansion (IOE), which extends the well known Opacity Expansion framework beyond the hard momentum transfer tail to the regime captured by the BDMPS-Z/ASW approximation. I will focus on the application of the IOE to the computation of the single gluon medium induced spectrum from a hard parton, which constitutes one of the most important theoretical results in jet quenching theory.
An important aspect of the study of Quark-Gluon Plasma (QGP) in ultra-relativistic collisions of heavy ions is the ability to identify a subset of jets that were strongly modified by the interaction with the QGP. In this talk, we will show how deep learning techniques can be applied for this purpose. Samples of $Z+$jet events were simulated in vacuum and medium and used to train deep neural networks with the objective of discriminating between medium- and vacuum-like jets. Dedicated Convolutional Neural Networks, Dense Neural Networks and Recurrent Neural Networks were developed and trained, and their performance will be shown. The results show the potential of these techniques for the identification of jet quenching effects induced by the presence of the QGP.
This talk gives an overview of the latest hard process measurements in heavy ion collision systems with the ATLAS detector at the LHC, utilizing the high statistics 5.02 TeV Pb+Pb data collected in 2018. These include multiple measurements of jet production and structure, which probe the dynamics of the hot, dense Quark-Gluon Plasma formed in relativistic nucleus-nucleus collisions; measurements of electroweak boson production to constrain the modifications of nuclear parton densities and test the Glauber model and binary scaling picture of heavy ion collisions; and measurements of quarkonia and heavy flavor production to probe the QGP medium properties. A particular focus of the measurements is the systematic comparison of fully unfolded data to state of the art theoretical models.
Jet interactions in a hot QCD medium created in heavy-ion collisions are conventionally assessed by measuring the modification of the distributions of jet observables with respect to the proton-proton baseline. However, the steeply falling production spectrum introduces a strong bias toward small energy losses that obfuscates a direct interpretation of the impact of medium effects in the measured jet ensemble. In this talk, we will explore the power of deep learning techniques to tackle this issue on a jet-by-jet basis.
Toward this goal, we employ a convolutional neural network (CNN) to diagnose such modifications from jet images where the training and validation is performed using the hybrid strong/weak coupling model. By analyzing measured jets in heavy-ion collisions, we extract the original jet transverse momentum, i.e., the transverse momentum of an identical jet that did not pass through a medium, in terms of an energy loss ratio. Despite many sources of fluctuations, we achieve good performance and put emphasis on the interpretability of our results. We observe that the angular distribution of soft particles in the jet cone and their relative contribution to the total jet energy contain significant discriminating power, which can be exploited to tailor observables that provide a good estimate of the energy loss ratio.
With a well-predicted energy loss ratio, we study a set of jet observables to estimate their sensitivity to bias effects and reveal their medium modifications when compared to a more equivalent jet population, i.e., a set of jets with similar initial energy. Then, we show how this new technique provides unique access to the initial configuration of jets over the transverse plane of the nuclear collision, both with respect to their production point and initial orientation. Finally, we demonstrate the capability of our new method to locate with unprecedented precision the production point of a dijet pair in the nuclear overlap region, in what constitutes an important step forward towards the long term quest of using jets as tomographic probes of the quark-gluon plasma.
[1] Yi-Lun Du, Daniel Pablos, Konrad Tywoniuk, Deep learning jet modifications in heavy-ion collisions, arXiv:2012.07797 [hep-ph], JHEP. 2021, 206 (2021)
Medium-induced gluon radiation is known to be an important tool to extract the properties of the QGP created in heavy-ion collisions. I will use a recent approach to evaluate the full in-medium gluon emission spectrum, including the resummation of all multiple scatterings, to analyze the validity of the usually employed analytical approximations. More specifically, by using this all-order result I will determine the kinematic regions in which the effects of multiple scatterings are essential and where, in contrast, a single hard scattering is enough to describe the in-medium emission process. Furthermore, I will compute the effects due to the inclusion of a time delay in the production of the medium has on the emission spectrum.
We calculate the resummed perturbative free energy of ${\cal N}=4$ supersymmetric Yang-Mills in four spacetime dimensions through second order in the 't Hooft coupling $\lambda$ at finite temperature and zero chemical potential. Our final result is ultraviolet finite and all infrared divergences generated at three-loop level are canceled by summing over ${\cal N}=4$ supersymmetric Yang-Mills ring diagrams. Non-analytic terms at ${\cal O}({\lambda}^{3/2}) $ and $ {\cal O}({\lambda}^2 \log\lambda )$ are generated by dressing the $A_0$ and scalar propagators. The gauge-field Debye mass $m_D$ and the scalar thermal mass $M_D$ are determined from their corresponding finite-temperature self-energies. Based on this, we obtain the three-loop thermodynamic functions of ${\cal N}=4$ supersymmetric Yang-Mills to ${\cal O}(\lambda^2)$. We compare our final result with prior results obtained in the weak- and strong-coupling limits and construct a generalized Pad\'{e} approximant that interpolates between the weak-coupling result and the large-$N_c$ strong-coupling result. Our results suggest that the ${\cal O}(\lambda^2)$ weak-coupling result for the scaled entropy density is a quantitatively reliable approximation to the scaled entropy density for $0 \leq \lambda \le 2$.
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The phase transition from hadronic material to quark-gluon plasma (QGP) is a phenomenon that occurs under extreme conditions of high temperature and high density. The QGP causes energy loss of high momentum particles which is observed as a suppression of high momentum hadron production in A+A collisions relative to p+p collisions. PHENIX, one of the relativistic heavy ion collider (RHIC) experiments at Brookhaven National Laboratory, aims to measure various QGP signals from nuclear collision reactions. The study presented in this talk uses PHENIX data to evaluate the energy loss of partons in QGP in various collision systems. We systematically study the energy loss with $\pi^0s$ in Au+Au and Cu+Au and Cu+Cu at $\sqrt{s_{NN}}$=200 GeV and charged hadrons in Au+Au at $\sqrt{s_{NN}}$=200 GeV using two quantities, $S_{loss}$ and $dp_T$. $S_{loss}$ represents the percentage of high $p_T$ hadron momentum loss. Previous studies revealed the the scaling properties of $S_{loss}$ on collision system size. The current study uses $S_{loss}$ to quantify energy loss dependence on path-length and measures $dp_T$ which is the difference in momentum loss between the in-plane and out-of-plane directions.
The interpretation of these results and their impact on our understanding of the path-length dependence of energy loss in the QGP will be discussed.
The High Acceptance DiElectron Spectrometer (HADES) is dedicated to the measurement of electromagnetic probes from heavy ion collisions and to study the in-medium behaviour of dileptons in the moderate temperature and high density regime of the QCD phase diagram. The spectral distributions of dileptons reveal the thermal properties of the medium. With the recent upgrade of the HADES RICH detector an unprecedented quality and signal-to-background ratio was achieved in the detection of these extremely rare probes.
In this talk we present preliminary results on the dielectron analysis of the HADES Ag+Ag data at a centre-of-mass energy of $\sqrt{s_{NN}} = 2.55 \, GeV$. The high statistics of the HADES data taking in combination with a strongly increased electron detection efficiency allow even for a signal in the $\Phi$-meson mass region. The obtained dielectron signal spectrum will be compared to simulated hadronic cocktail and nucleon-nucleon reference spectra clearly revealing a contribution from the medium.
NA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a fixed target experiment located at the CERN SPS. Its strong interactions programme is devoted to study properties of the phase diagram of strongly interacting matter. For this goal the two-dimensional scan is performed by measurements of hadron production properties as a function of collision energy (13A - 158A GeV/c) and system size (p+p, p+Pb, Be+Be, Ar+Sc, Xe+La, Pb+Pb). This contribution presents new results on the onset of deconfinement - the transition between the state of hadronic matter and the quark-gluon plasma. Also, new results on fluctuations and correlations devoted to the search for the critical point of strongly interacting matter will be presented. Obtained results will be compared with available data from other experiments and from various theoretical models.
Finite magnetic field is relevant for both systems where QCD matter can be studied in practice - heavy ion collisions and neutron stars. It was shown recently, that in sufficiently strong magnetic fields and at moderate baryon densities a new phase of QCD matter appears: a crystalline condensate of neutral pions named the chiral soliton lattice. This phase might be relevant for magnetars; however, in order to assess its relevance for heavy ion collisions, finite temperature has to be taken into account. In this talk, I will describe the effects of quantum fluctuations and finite temperature recently calculated within chiral perturbation theory. The obtained results on the QCD phase diagram for varying temperature, baryon chemical potential and magnetic field will be presented.
Information for speakers about talk's duration:
30 min slot= 25 to speak + 5 for questions
25 min slot= 20 to speak + 5 for questions
20 min slot = 17 to speak + 3 for questions
Conveners for Sunday Neutrino sessions
13:00 José Valle
14:45 Kendall Mahn
16:30 Kendall Mahn
Conveners for Wednesday Neutrino sessions
13:00 José Valle
14:45 José Maneira
16:30 José Maneira
Coherent elastic neutrino-nucleus scattering (CEvNS) is a process in which a neutrino scatters off an entire nucleus. Measurements will further the search for BSM physics and bring new insights to topics in nuclear physics and astrophysics. CEvNS has now been observed in CsI and Ar by the COHERENT collaboration. A number of experiments are pursuing further measurements, making use of a variety of neutrino sources and detector technologies. This talk will explore the physics reach of CEvNS experiments, the status of the current experimental program, and prospects for the future.
The CONUS experiment aims at detecting coherent elastic neutrino nucleus scattering (CE$\nu$NS) at the nuclear power plant in Brokdorf, Germany, which has a maximum thermal power of 3.9GW$_{th}$. Four low energy threshold high-purity point contact Germanium spectrometers are set up in an elaborate shield achieving background levels comparable to experiments located much deeper underground.
With the data collected during Run-1 and Run-2 of the experiment and a full spectral analysis it was possible to determine the most stringent upper limit on CEvNS with reactor antineutrino in the fully coherent regime so far. This will be shown in the talk. Moreover, novel limits on physics beyond the standard model can be set such as on non-standard interactions (NSIs) in the neutrino-quark sector and on the neutrino magnetic moment. An overview on the latest results will be presented in the talk.
Detection of coherent elastic neutrino nucleus-scattering (Cevns) has been recently confirmed. The low-energy region of this process and its neutral current character, allows to explore beyond the Standard Model particle physics in complementary regions to other searches. In this talk I will review the current status and future perspectives of such constraints with a special focus on non-standard interactions.
The recent observation of coherent elastic neutrino nucleus scattering (CEvNS) has opened new opportunities for investigating nuclear structure parameters and other electroweak probes. In this talk I will present the current status of constraints on the nuclear neutron rms radii of CsI and Argon, placed by the COHERENT data. I will also review the implications of advanced nuclear structure models, such as the deformed shell model and the quasiparticle random phase approximation (QRPA), on the interpretations of new physics signals with a special focus on electromagnetic neutrino interactions.
In this talk we will present the first measurement of the neutron skin of cesium and iodine using electroweak probes, coherent elastic neutrino-nucleus scattering and atomic parity violation. This measurement, differently from hadronic probes, is model-independent and suggests a preference for nuclear models which predict large neutron skin values, with implications that range from neutron stars to heavy ion collisions.
Moreover, we will show a new determination of the low-energy weak mixing angle, with a percent uncertainty, fully determined from electroweak processes and independent of the neutron radius of cesium, allowed to vary in the fit. This will permit to put reliable constraints to theories beyond the standard model.
T2K is an accelerator-based neutrino experiment providing world-leading measurements of the parameters governing neutrino oscillation. T2K data enabled the first 3sigma exclusion for some intervals of the CP-violating phase \delta_{CP} and precision measurements of the atmospheric parameters \Delta_m^{2}{32}, sin^2(\theta{23}). T2K uses a beam of muon neutrinos and antineutrinos produced at the Japan Particle Accelerator Research Centre (JPARC) and a series of detectors located at JPARC and in Kamioka, 295km away, to measure oscillation from neutrino event rates and spectra. The T2K beam will be upgraded with increased power in 2022 and, combined with an upgrade of the ND280 near detector, will usher in a new important physics period for T2K. In addition, the Super-Kamiokande detector has been loaded with 0.02% of Gadolinium in 2020, enabling enhanced neutron tagging. In preparation for the new physics run, the T2K collaboration is working on an updated oscillation analysis to improve the control of systematic uncertainties. A new beam tuning has been developed, based on an improved NA61/SHINE measurement on a copy of the T2K target and including a refined modelling of the beam line materials. New selections have been developed at ND280, with proton and photon tagging, and at Super-Kamiokande, where pion tagging has been extended to muon neutrino samples. After reviewing the latest measurements of oscillation parameters, the status of such new analysis developments and the plan to deploy the beam and ND280 upgrade will be presented.
The Hyper-Kamiokande experiment consists of a 260 kt underground water Cherenkov detector with a fiducial volume more than 8 times larger than that of Super-Kamiokande. It will serve both as a far detector of a long-baseline neutrino experiment and an observatory for astrophysical neutrinos and rare decays. The long-baseline neutrino experiment will detect neutrinos originating from the upgraded 1.3 MW neutrino beam produced at the J-PARC accelerator. A near detector suite, close to the accelerator, will help characterise the beam and minimise systematic errors. The experiment will investigate neutrino oscillation phenomena (including CP-violation and mass ordering) by studying accelerator, solar and atmospheric neutrinos, neutrino astronomy (solar, supernova, supernova relic neutrinos) and nucleon decays. An overview of the Hyper-Kamiokande experiment, its current status and physics sensitivity will be presented.
The NOvA experiment is a long-baseline accelerator-based neutrino oscillation experiment that uses the upgraded NuMI beam from Fermilab to measure electron-neutrino appearance and muon-neutrino disappearance between the Near Detector, located at Fermilab, and the Far Detector, located at Ash River, Minnesota. NOvA's primary physics goals include precision measurements of oscillation parameters, such as $\theta_{23}$ and the atmospheric mass-squared splitting, along with probes of the mass hierarchy and of the CP-violating phase. This talk will cover NOvA’s most recent three-flavor oscillation results, based on a neutrino beam exposure of 13.6E20 protons-on-target and an anti-neutrino beam exposure of 12.5E20 protons-on-target.
The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose neutrino experiment currently under construction in South China, expecting to start data taking in 2023. JUNO primary goal is the determination of the neutrino mass ordering and the measurement at a sub-percent level three of the neutrino oscillation parameters and thanks to the detection of reactor antineutrinos at a medium baseline (53 km). The main detector, placed in a cavern 700 m underground, will consist of 20 kton of liquid scintillator contained in a 35.4 m diameter acrylic sphere, becoming the largest detector of its kind ever built in the world. JUNO will be instrumented with 17,612 20” photomultiplier tubes (PMTs), and 25,600 3” PMTs reaching a photo-coverage above 75%, and will achieve an unprecedented energy resolution of 3%/√E(MeV) thanks to a comprehensive calibration system, among others. The acrylic sphere will be submerged in a water pool Cherenkov detector and covered on the top by layers of plastic scintillator to tag cosmic ray muons, a major source of background. During this talk the project’s design and status will be presented.
In this talk, I will present the current status of global analyses to neutrino oscillation data in the three-flavor framework. I will discuss the recent hints in favor of normal mass ordering and maximal CP violation and the tensions that appear from the combination of different data samples. I will also comment on future opportunities to improve our knowledge of the oscillation picture as well as on its robustness in the presence of new physics beyond the Standard Model.
Search for eV Sterile Neutrinos -- The STEREO Experiment
Mathieu Vialat on behalf of the STEREO collaboration\
In the recent years, the study of reactor antineutrinos has revealed two unsolved anomalies. The first one is related to the neutrino spectral shape where an excess of detected neutrinos compared to the model is observed around $5~$MeV. The second anomaly, called Reactor Antineutrino Anomaly (RAA), is a deficit of the detected neutrino flux compared to the expected one. This phenomenon could be explained by an oscillation to a new light sterile neutrino. It can be tested by searching for oscillations at a reactor with very short baselines.
The STEREO experiment was installed at $\sim10~$m from the compact core, highly enriched in $^{235}$U, of the research reactor of the Institut Laue-Langevin (Grenoble, France). The detector has been designed to search for a new light sterile neutrino in the parameter region of the RAA best fit parameters ($\Delta m²_{41}$ = 2.3 eV$²$ and sin$²(2\theta_{ee}) = 0.17 )$, but also to characterize the flux and the shape of the pure $^{235}$U spectrum. Data were taken between November 2016 and November 2020. STEREO has been able to exclude a significant part of the parameter space with a dataset of 179 (211) days reactor on (off) data. A measurement of the absolute flux, with the best precision for a single experiment at a reactor with highly enriched $^{235}$U, has also been achieved. Finally the STEREO analysis provided a neutrino energy spectrum which shows an excess, compared to the rate-normalized Huber model, around 5 MeV similar to the one reported by other reactor experiments.
In this contribution we will give an overview of the STEREO experiment. Then, updated results obtained with the whole STEREO dataset,
collecting 334 (543) days on (off), will be presented.
The ICARUS collaboration employed the 760-ton T600 detector in a successful three-year physics run at the underground LNGS laboratories studying neutrino oscillations with the CNGS neutrino beam from CERN, and searching for atmospheric neutrino interactions. ICARUS performed a sensitive search for LSND-like anomalous νe appearance in the CNGS beam, which contributed to the constraints on the allowed parameters to a narrow region around 1 eV$^2$, where all the experimental results can be coherently accommodated at 90% C.L. After a significant overhaul at CERN, the T600 detector has been installed at Fermilab. In 2020 cryogenic commissioning began with detector cool down, liquid Argon filling and recirculation. ICARUS has started operations and is presently in its commissioning phase, collecting the first neutrino events from the Booster Neutrino Beam and the NuMI off-axis. The main goal of the first year of ICARUS data taking will then be the definitive verification of the recent claim by NEUTRINO-4 short baseline reactor experiment both in the $\nu_\mu$ channel with the BNB and in the $\nu_e$ with NuMI. After the first year of operations, ICARUS will commence its search for evidence of a sterile neutrino jointly with the SBND near detector, within the Short Baseline Neutrino (SBN) program. The ICARUS exposure to the NuMI beam will also give the possibility for other physics studies such as light dark matter searches and neutrino-Argon cross section measurements. The proposed contribution will address ICARUS achievements, its status and plans for the new run at Fermilab and the ongoing developments of the analysis tools needed to fulfill its physics program.
SND@LHC is a compact and stand-alone experiment to perform measurements with neutrinos produced at the LHC in a hitherto unexplored pseudo-rapidity region of 7.2 < η < 8.6, complementary to all the other experiments at the LHC. The experiment is to be located 480 m downstream of IP1 in the unused TI18 tunnel. The detector is composed of a hybrid system based on an 800 kg target mass of tungsten plates, interleaved with emulsion and electronic trackers, followed downstream by a calorimeter and a muon system. The configuration allows efficiently distinguishing between all three neutrino flavours, opening a unique opportunity to probe physics of heavy flavour production at the LHC in the region that is not accessible to ATLAS, CMS and LHCb. This region is of particular interest also for future circular colliders and for predictions of very high-energy atmospheric neutrinos. The detector concept is also well suited to searching for Feebly Interacting Particles via signatures of scattering in the detector target. The first phase aims at operating the detector throughout LHC Run 3 to collect a total of 150 fb−1. The experiment was recently approved by the Research Board at CERN. A new era of collider neutrino physics is just starting.
Information for speakers about talk's duration:
15 min slots: 12 to speak + 3 for questions
20 min slots: 15 to speak + 5 for questions
Understanding the structure of strongly-interacting quantum mechanical systems such as atomic nuclei is a formidable challenge in physics. We recently demonstrated the feasibility to access nucleon-nucleon Short-Range Correlations (SRCs) in nuclei using hadronic probes in inverse kinematics [1]. The experiment was carried out at the JINR (Russia), a $^{12}$C beam at 48 GeV/c impinged on a liquid hydrogen target where the reaction products were measured kinematically complete with the BM@N detector setup. At first, by measuring the fragment in the $^{12}$C$(p,2p)^{11}$B reaction limitations posed by final-state interactions are overcome and single nucleon properties are shown to be probed in a distinct single-step knockout reaction. The extracted ground-state distributions are in agreement with theoretical calculations. We probe SRCs in the same way by the break up of SRC nucleon pairs in $^{12}$C$(p,2pN)^{10}$B/$^{10}$Be reactions. SRCs are not only identified for the first time in such kinematical conditions but also their properties like factorization are deduced in this direct measurement. This experimental technique opens the pathway for SRC studies in short-lived nuclei at upcoming accelerator facilities like FAIR. We will also perform a follow-up experiment at JINR end of 2021, which will take advantage of a new proton-detection system.
[1] M. Patsyuk, J. Kahlbow, G. Laskaris et al. (BM@N Collaboration), Nature Physics (2021).
https://doi.org/10.1038/s41567-021-01193-4
The present new and very exciting multi-messenger era for the astronomy, nuclear, gravitational and astrophysics community was set by the detection of gravitational wave signals from the collision of two neutron stars (NS) by the LIGO and Virgo interferometers in 2017, followed up by the detection of the gamma-ray burst GRB170817A and the electromagnetic transient AT2017gfo. Later, in 2019, a second and third signals, GW190425 and GW190814, were detected, the first one a larger system than those of any binary NS known to date, and the latter a system involving the collision of a black hole with a 2.5-2.67 Msun compact object, that has not been ruled out yet to be a NS. The NICER collaboration has published new radius and mass measurements from PSRJ0030+0451 [1], and very recently from PSRJ0740+6620 [2], which have been able to set new constraints in NS matter.
In the near future, the large amount of new data that will be made available by SKA will allow us to determine NS properties with much smaller uncertainties and set strong constraints on the equation of state of stellar matter. Neutron stars will, as a consequence, become a real laboratory to test the nuclear force under extreme conditions of density, proton-neutron asymmetry and temperature.
Light (deuterons, tritons, helions, α−particles), and heavy (pasta phases) nuclei exist in nature not only in the inner crust of neutron stars (cold β−equilibrium matter), but also in core-collapse supernova matter and NS mergers (warm nuclear matter with fixed proton fraction). The appearance of these clusters can modify the neutrino transport, and, therefore, consequences on the dynamical evolution of supernovae and on the cooling of proto-neutron stars are expected. However, a correct estimation of their abundance implies that an in-medium modification of their binding energies is precisely derived.
In this talk, we will address not only from the theoretical point of view how these clusters are calculated for warm stellar matter in the framework of relativistic mean-field models with in-medium effects [3], but also how these models are calibrated to experimental data from heavy-ion collisions [4, 5], measured by the INDRA Collaboration [6]. We show that this in-medium correction, which was not considered in previous analyses from heavy-ion collisions, is necessary, since the observables of the analyzed systems show strong deviations from the expected results for an ideal gas of free clusters. It turns out that the resulting light cluster abundances come out to be in reasonable agreement with constraints at higher density coming from heavy ion collision data. Some comparisons with microscopic calculations are also shown.
References:
[1] T.E. Riley et al, ApJ. Lett. 887, L21 (2019); M.C.Miller et al, ApJ. Lett. 887, L24 (2019).
[2] T. E. Riley et al, arXiv:2105.06980; M. C. Miller et al, arXiv:2105.06979.
[3] H. Pais, F. Gulminelli, C. Providência, and G. Röpke, Phys. Rev. C 97, 045805 (2018).
[4] H. Pais, R.Bougault, F.Gulminelli, C. Providência et al., Phys. Rev. Lett. 125, 012701 (2020).
[5] H. Pais, R.Bougault, F.Gulminelli, C. Providência et al., J. Phys. G: Nucl. Part. Phys. 47, 105204 (2020).
[6] R. Bougault et al., J. Phys. G: Nucl. Part. Phys. 47, 025103 (2020).
The ab initio description of nuclear systems has undergone a major renewal due to the use of low-resolution interactions derived from chiral effective field theory in conjunction with many-body techniques admitting for mild computational scaling [1].
Nowadays many-body practitioners are able to target systems with up to one hundred interacting particles from first principles in a systematically controllable way [2].
In this talk I present recent advances in the field of ab initio nuclear theory in the context of the non-perturbative in-medium similarity renormalization group (IMSRG) approach.
While the many-body expansion is commonly built upon a simple Hartree-Fock state, basis optimisation tools have shown to significantly improve the modelsapce convergence of the calculation [3,4]. In addition, by including three-body contributions induced by the RG flow enables for an improved many-body solution using ab initio technology [5].
Optimising the underlying reference state as well as relaxing the many-body truncation will eventually pave the way for high-precision studies in medium-mass systems.
[1] H. Hergert, Front. Phys. 8, 379 (2020).
[2] T. Morris et al., Phys. Rev. Lett. 120, 152503 (2018)
[3] A. Tichai, J. Müller, K. Vobig and R. Roth, Phys. Rev. C 99, 034321 (2019)
[4] J. Hoppe, A. Tichai, M. Heinz, K. Hebeler and A. Schwenk, Phys. Rev. C 103, 014321 (2021)
[5] M. Heinz, A. Tichai, J. Hoppe, K. Hebeler and A. Schwenk, Phys. Rev. C 103, 044318 (2021)
Atomic and molecular ions contained in RF traps are demonstrating to provide some of the most precise measurements possible of electron-nucleon interactions.
Atoms and molecules containing radioactive nuclei are predicted to offer significant enhancements to constrain beyond the Standard Model effects, including searches for time-reversal symmetry, dark matter candidates and yet to be observed nuclear properties.
However, radioactive atoms and molecules present challenges for precision spectroscopy: they are produced at low rates (often <1000 per second), in hot environments (>300 K) and require accelerated beam energies to isolate (>10 keV).
This contribution presents a setup under construction to efficiently adapt bunches of radioactive ions to a cryogenic ion trapping environment, which will additionally permit electric-field polarisation of molecules to allow for searches of eEDMs, nuclear Schiff moments and magnetic quadrupole moments.
Lightest elements were produced in the first few minutes of the Universe through a sequence of nuclear reactions known as Big Bang nucleosynthesis (BBN).
Although astronomical observations of primordial deuterium abundance have reached percent accuracy, theoretical predictions based on BBN are affected by the large uncertainty on the cross-section of the D(p,γ)3He deuterium burning reaction.
I will report on a new measurement of the D(p,γ)3He cross section performed by the LUNA collaboration to an unprecedented precision of better than 3%. This result settles the most uncertain nuclear physics input to BBN calculations and substantially improve the use of primordial abundances as probes of the physics of the early Universe.
In the last two decades atmospheric, solar, reactor and accelerator experiments have precisely measured neutrino squared mass differences and mixings, responsible for neutrino vacuum oscillations. An intense experimental program will keep addressing unknown neutrino properties including neutrino mass ordering and mass scale, the neutrino nature, the existence of sterile neutrinos, of CP violation and also non-standard interactions.
Neutrinos play an important role in astrophysics. Beyond the established Mikheev-Smirnov-Wolfenstein effect, novel neutrino flavor mechanisms are uncovered in particular in dense environments such as core-collapse supernovae and binary compact mergers remnants, where elements heavier than iron can be synthetised through the r-process. In this talk, I will highlight the importance of flavor evolution in dense media, in connection with future observations and with GW170817. I will also stress the interplay with non-standard physics.
The astrophysical sites where r-process elements are synthesized remain mysterious: it is clear that neutron-star mergers (kilonovae, KNe) contribute, and some classes of core-collapse supernovae (SNe) are also likely sources of at least the lighter r-process species. The discovery of the live isotope Fe60 on the Earth and Moon over the past decades implies that one or more astrophysical explosions occurred near the Earth (within ~100pc) within the last few Myr, probably a SN. Intriguingly, several groups have reported evidence for deposits of Pu244, some overlapping with the Fe60 pulse, but pointing to a different origin like KNe. Motivated by the Pu244 observations, we propose that ejecta from a KN enriched the giant molecular cloud that gave rise to the Local Bubble in which the Sun resides. This hypothesis is also consistent with the most recent Pu244 measurements by Wallner et al. (2021).
Accelerator Mass Spectrometry (AMS) measurements of Pu244 and searches for other live isotopes could probe the origins of the r-process and the history of the solar neighborhood, including triggers for mass extinctions, e.g., at the end of the Devonian epoch. Thus, we carried out the nucleosynthesis calculations of the abundances of live r-process radioisotopes produced in SNe and KNe. Given the presence of Pu244, other r-process species such as Zr93, Pd107, I129, Cs135, Hf182, U236, Np237 and Cm247 should be present. Their abundances could distinguish between SNe and KNe scenarios, and we discuss prospects for their detection in deep-ocean deposits and the lunar regolith. With current AMS sensitivities, I129 is the most promising isotope to detect, and we find that the AMS I129 measurements in Fe-Mn crusts already constrain a possible nearby KNe scenario. Thus, we urge searches for r-process radioisotopes in deep-ocean Fe-Mn crusts, and in the lunar regolith samples brought to Earth recently by the Chang’e-5 lunar mission and upcoming missions including Artemis.
The observation of the near-infrared emission from binary neutron-star
merger events, often know as kilonova, has increased the confidence
that these astrophysical sources are the potential sites of heavy
r-process nucleosynthesis. This emission is present in the
observations of the gravitational-wave signal (GW170817) by LIGO/Virgo
and is consistent with an electromagnetic transient emission of a
kilonova. However, data of opacities, necessary for the interpretation
of these observations, relies heavily on atomic structure calculations
of both lanthanides and actinides, which is still very sparse. In this
work we discuss the details of these calculations and some of the
limitations imposed by the complexity of f-shell elements. Besides
reviewing some previous results, we compare them with our present
calculations based on the the atomic structure codes FAC and MCDFGME.
We study the combined effect of transition wavelengths and oscillator
strengths on the opacities and how energy precision can be important
at lower wavelengths. Finally, we discuss how higher sensitivity of
the opacity curve at higher energies can be exploited, looking for
features of specific of lantanides and actinides present in kilonovae.
A measurement of the transmission coefficient for neutrons through a thick ($\sim 3$\,atoms/b) liquid natural argon target in the energy range $30$-$70$\,keV was performed by the Argon Resonance Transmission Interaction Experiment (ARTIE) using a time of flight neutron beam at Los Alamos National Laboratory.
In this energy range theory predicts an anti-resonance in the $^{40}$Ar cross section near $57$\,keV, but the existing data, coming from an experiment performed in the 90s (Winters. et al.), does not support this.
This discrepancy gives rise to significant uncertainty in the penetration depth of neutrons through liquid argon, an important parameter for next generation neutrino and dark matter experiments.
In this talk, the first results from the ARTIE experiment will be presented.
The ARTIE measurement of the total cross section as a function of energy confirms the existence of the anti-resonance near $57$\,keV, but not as deep as the theory prediction.
The FRIB S800 superconducting spectrograph is used for studying nuclear reactions induced by high-energy radioactive beams. The spectrometer was designed for high-precision measurements of small scattering angles (within ±2 msr), combined with the large acceptance of the solid angle (20 msr) and momentum (6%). The high-resolution (1/10,000) is optimized for energies up to 200 MeV/u. The S800 has been an indispensable apparatus for the wide physics program of the NSCL with fast rare isotope beams, being the most heavily used experimental device at NSCL. The S800 spectrograph will continue to serve the nuclear physics/astrophysics community for experiments with rare isotope beams also during FRIB operation.
A crucial component for the performance of the S800 spectrometer is the focal plane detector system, which consists of an array of various detector technologies for trajectory reconstruction as well as particle identification (PID). This includes two x/y drift chambers for tracking, an ionization chamber for atomic number identification by energy loss measurement, and a plastic scintillator for timing (as well as energy loss). Downstream the plastic scintillator, a CsI(Na) hodoscope is deployed to identify atomic charge states of the implanted nuclei via total kinetic energy (TKE) measurement. In this work, the operational mechanism and performance of novel detector concepts planned for the upgrade of the S800 focal plane are described for the first time. In particular, we will present the design of the new drift chamber (DC) readout based on a hybrid Micro-Pattern Gaseous Detector structure. Performance evaluations under irradiation with small lab source (5.6 MeV alpha–particle emitted by an Am-241 source) as well as with test heavy-ion beams will be presented and discussed in detail. In the latter case we the detector was irradiated by a 78Kr36+ beam at around 150 MeV/u, as well as by a heavy-ion fragmentation cocktail produced by the 78Kr beam impinging on a Be target.
In addition, I will present the development of a heavy-ion particle identification (PID) device based on an energy-loss measurement (ΔE) within a novel optical scintillation scheme. The new instrument consists of a multi-segmented optical detector (ELOSS) filled with high-luminescence yield gas (e.g. pure Xenon). Its operational principle is based on recording the fast scintillation light emitted along an ion’s track. This developing technology allows for high-resolution ΔE measurements at a high counting rate, unlike traditional ionization chambers. Both high energy resolution and high counting rate capabilities are needed to take full advantage of the future FRIB’s rare-isotope beam portfolio and anticipated high intensity. The proposed detector presents a significant advance in both instrumentation and capabilities in the field of experimental nuclear physics, providing new opportunities for experiments with rare isotope beams.
The reaction network in the neutron-deficient part of the nuclear chart around A$\sim$100 contains several nuclei of importance to astrophysical processes, such as the p-process. This work reports on the results from recent experimental studies of the radiative proton-capture reactions $^{112,114}$Cd(p,γ)$^{113,115}$In. Isotopically enriched $^{112}$Cd and $^{114}$Cd targets have been used for the determination of the cross sections, for proton beam energies residing inside the respective Gamow windows for each reaction. Two different techniques, the in-beam γ-ray spectroscopy and the activation method have been implemented, where the latter is considered mandatory to account for the presence of low-lying isomers in $^{113}$In (E$\approx$392 keV, $t_{1/2}\sim$100 min), and $^{115}$In (E$\approx$336 keV, $t_{1/2}\sim$4.5 h). Following the measurement of the cross sections, the astrophysical S factors have been subsequently deduced. The experimental results are compared to detailed Hauser-Feshbach theoretical calculations carried out with TALYS v1.95. The results are expected to shed light in the nucleosynthetic mechanisms of the p-process in neutron-deficient nuclei, where scarce experimental data exist.
Proton capture reactions at sub-barrier energies have significant
contributions in explosive nucleosynthesis environments. In
particular, they are crucial to determine the reaction rate of the
inverse (g,p) reaction in reaction networks describing the production
of the stable p-nuclei, a set of 35 naturally occurring nuclei from Se
to Hg that cannot be produced in neutron capture processes like the
s-process or the r-process.
In this work, we present the measurement for the first time of the
radiative proton capture reaction 118Sn(p,g)119Sb using the activation
method by detecting the emitted X-rays. The gamma emission associated
to the electron capture decay in 119Sb will be used to validate the
method. The results are compared to theoretical predictions using the
TALYS code, and show the potential of using this technique to further
constrain the nuclear input in astrophysical network calculations.
Neutron induced reactions play a significant role in the
nucleosynthesis of the elements in the cosmos. Its interest ranges
from the primordial processes occurred during the Big Bang
Nucleosynthesis up to the "stellar cauldrons" where neutron
capture reactions could take place via the s-process or the r-process.
In the last years, several efforts have been made to investigate the
possibility of applying the Trojan Horse Method (THM) to neutron
induced reactions mostly by using deuteron as "TH-nucleus". Here,
the main advantages of using THM will be given together with a more
focused discussion on the recent 7Be(n,alpha)4He and the 14N(n,p)14C
reactions. The former reaction was studied via the THM application to
the quasi-free 2H(7Be,aa)p reaction and it represents the extension of
the method to neutron-induced reactions in which an unstable beam is
present. The 14N(n,p)14C reaction was studied via the 2H(14N,p14C)p
experiment performed at INFN-LNS via a 50 MeV 14N beam provided by the
TANDEM accelerator. The preliminary data analysis will be also shown.
The Laboratory for Underground Nuclear Astrophysics (LUNA) is an experiment located in deep underground at Gran Sasso National Laboratories (LNGS). Its mission is to study charged-particle induced nuclear reactions of astrophysical interest.
This is an unique experiment that combines low environmental background and an intense and long term stable proton or alpha beam. The combination of these two peculiarities allowed in the last decades to provide valuable contributions to our present understanding of primordial nucleosynthesis, as well as stellar hydrogen and helium stellar burning.
In this framework, very recent measurements were performed for the direct measurement of the $^{13}$C($\alpha$,n)$^{16}$O reaction cross section.
This process constitutes the dominant neutron source for the main s process, responsible of nucleosynthesis of half on nuclides heavier that iron, in low mass stars of thermally pulsing Asymptotic Giant Branch.
For the first time, the LUNA experiment developed a low intrinsic background neutron detector that combined with a detailed Low Level Counting analysis and an accurate target monitoring allowed to measure the $^{13}$C($\alpha$,n)$^{16}$O cross section with unprecedented results, reaching the edge of the Gamow peak with an overall uncertainty of 20% at maximum.
In this talk I will present the LUNA experiment, focusing the attention techniques that led the cross section results of the $^{13}$C($\alpha$,n)$^{16}$O reaction, illustrating the new reaction rate and its astrophysical implications.
Resonance phenomena appearing in low-energy nuclear reactions are very important in studies of nucleosynthesis in cosmos because reaction rates in the synthesis are strongly affected by the resonance parameters: resonance energy and decay width. In particular, the inelastic scattering to the continuum energy states above the particle decay threshold, which is often called breakup reaction, is very useful to explore the resonance parameters.
In order to derive the resonance parameters from the observed strength of the breakup reactions, the evaluation of the non-resonant background strength is indispensable because the resonant enhancement, which has the strong energy dependence, are embedded in the non-resonant background contribution with a broad structure. Since the background strength is structure-less and must have the weak energy dependence, the shape of the non-resonant background strength is often assumed by the simple analytic function or evaluated from the simple reaction mechanism, such as the direct breakup without the final state interaction between the decaying fragments. Unfortunately, there is no theoretical prescription to describe the non-resonant background strength on the basis of the simple analytic formula.
In this report, we propose an analytic formula to evaluate the non-resonant background strength by extending the Midgal-Watson (MW) theory, which was originally considered for the s-wave breakup reaction in the charge neutral systems. In the evaluation of the background strength for the binary breakup, we employ the complex scaling method (CSM), which is a powerful tool to describe the few-body continuum states.
We have calculated the non-resonant breakup strength of $^{20}$Ne into $\alpha$ + $^{16}$O and $^{12}$Be into $\alpha$ + $^8$He by CSM, and the CSM strength is fitted by the analytic function, which is obtained by the extended MW formula. We will demonstrate that our analytic formula can nicely reproduce the non-resonant strength in these binary breakup reactions. Moreover, we will report the physical meaning of new parameters, which are introduced in extending the original MW formula, in connection to the spatial size of the initial wave function in the breakup reactions.
The partial half-life of $^{190}Pt$ for the alpha decay to the first excited level ($E_{exc}=137.2$ keV) of $^{186}Os$ was measured using an ultralow-background HPGe-detector system located 225 m underground in the laboratory HADES (Belgium). A sample of high purity platinum (the purity grade is 99.95%) with a mass of 148.122 g was used and measured during 373 days. Preliminary, the partial half-life of $^{190}Pt$ is estimated as $T_{1/2}=(2.2\pm0.4)\times10^{14}$ yr. Measurements of the $^{190}Pt$ isotopic concentration in the platinum sample are in progress at the John de Laeter Centre at Curtin University (Perth, Western Australia) aiming to further reduce the half-life value uncertainty.
Information for speakers about talk's duration:
18 min slot= 15 to speak + 3 for questions
15 min slot= 12 to speak + 3 for questions
We present a new release of the NNPDF family of global analyses of parton distribution functions: NNPDF4.0. It includes a wealth of new experimental data from HERA and the LHC, from dijet cross-sections to single-top and top-quark pair differential distributions. The NNPDF4.0 methodology benefits from improved machine learning algorithms, in particular automated hyperparameter optimisation and stochastic gradient descent for neural network training, which has been validated extensively by means of closure tests and future tests. We demonstrate the stability of the result with respect to the choice of parameterisation basis. We compare NNPDF4.0 with its predecessor NNPDF3.1 as well as to other recent global fits, and study its phenomenological implications for representative collider observables. We assess the impact of representative datasets on specific PDF combinations, such as the dijet and top quark data on the gluon, the Drell-Yan and neutrino DIS data on strangeness, and electroweak measurements on charm and quark flavour separation.
Deeply Virtual Compton Scattering (DVCS) and Hard Exclusive Meson Production (HEMP) are very promising reactions to study Generalized Parton Distributions (GPDs). GPDs correlate the longitudinal momentum of the partons to their transverse spatial distribution inside the nucleon, and thus provide the 3-dimensional structure of the nucleon in QCD. Following a one-month test run in 2012, exclusive measurements were performed at COMPASS in 2016 and 2017 at the M2 beamline of the CERN SPS. The 160 GeV muon beam impinged on a 2.5m long liquid hydrogen target that was surrounded by a barrel-shaped time-of-flight system to detect the recoiling target proton. The scattered muons and the particles produced were detected by the COMPASS spectrometer, which was supplemented by an additional electromagnetic calorimeter for the large-angle-photon detection.
The DVCS cross section are extracted from the sum of cross-sections measured with opposite beam charge and polarization, with special attention made to separate DVCS from exclusive $\pi^0$ production. In the COMPASS kinematic domain, the DVCS cross section is closely related to the GPD $H$ and provide the transverse extension of the partons in the Bjorken-x regime between valence quarks and gluons. On the other hand, the measurement of the cross-section of exclusive $\pi^0$ production, and the Spin Density Matrix Elements (SDMEs) of $\rho^0$ and $\omega$ can not only serve as important inputs for the chiral-odd GPDs, together with the chiral-even ones, but also provide insights into their reaction mechanisms. The current progress on the study of these exclusive channels will be presented.
The COMPASS experiment, located in the North Area of CERN, has the study of nucleon structure as one of its main physics goals. In 2015 and 2018, COMPASS collected Drell-Yan and J/$\psi$ production data from the collisions of a 190 GeV negative pion beam on a transversely polarized ammonia target, and on a tungsten target. The study of the angular dependence of the dimuons produced provides valuable information on the transverse momentum dependent parton distribution functions (TMD PDFs) of both the nucleon and the pion. The measurement of target-spin dependent azimuthal asymmetries is of particular interest, as it can be used to test the predicted sign change of the Sivers TMD PDF when measured in the Drell-Yan process, as compared to the one measured in semi-inclusive deep inelastic scattering. The COMPASS experiment has the advantage of measuring both processes in very similar phase space. On the other hand, the transverse spin asymmetries measured in J/psi production may give access to the gluon Sivers TMD PDF, while improving our understanding of the charmonium production mechanisms. The most recent COMPASS results on dimuon angular dependences and target transverse spin dependent asymmetries will be presented.
The HERMES experiment has collected a wealth of data using the 27.6 GeV polarized HERA lepton beam and various polarized and unpolarized gaseous targets. This allows for a series of unique measurements of observables sensitive to the multidimensional (spin) structure of the nucleon, in particular semi-inclusive deep-inelastic scattering (SIDIS) measurements, for which the HERMES dual-radiator ring-imaging Cherenkov counter provided final-hadron identification between 2 GeV to 15 GeV for pions, kaons, and (anti)protons. In this contribution, longitudinal and transverse single- and double-spin asymmetries in SIDIS will be presented. The azimuthally uniform longitudinal double-spin asymmetries using longitudinally polarized nucleons constrain the flavor dependence of the quark-spin contribution to the nucleon spin. For a first time, such asymmetries are explored differential in three dimensions in Bjorken-x and the in the hadron kinematics z and 𝑃ℎ⊥ (which respectively represent the energy fraction and transverse momentum of the final-state hadron) simultaneously. This approach increases the quark-flavor sensitivity and allows one to probe the transverse-momentum dependence of the helicity distribution. The measurement of hadron charge-difference asymmetries allows, under certain simplifying assumptions, for the direct extraction of valence-quark polarizations. The azimuthal modulation of this double-spin as well as of the single-(beam)spin asymmetry probe novel quark-gluon-quark correlations through twist-3 distribution and fragmentation functions. Also here, asymmetries are explored in several dimensions. Furthermore, in case of the beam-spin asymmetry, results for electro-produced protons and antiprotons have become available. The beam-spin asymmetries for pions are compared to similar measurements for pions at CLAS and unidentified hadrons at COMPASS. Last but not least, a review of similar measurements using a transversely polarized target will be given, providing information on the novel Sivers and Collins effects, among others.Those go beyond the earlier measurements, which were restricted to mainly one-dimensional projections and to mesons, by a first three-dimensional extraction of transverse spin asymmetries for identified pions, charged kaons, as well as protons and antiprotons, and including all single- and double-spin modulations allowed for lepton scattering on a transversely polarized proton target.
A key step towards a better understanding of nucleon structure in terms of generalized parton distributions (GPDs) is the measurement of deeply virtual Compton scattering off the neutron (nDVCS; $ed\to e'n\gamma(p)$). This process emphasizes mainly, in the kinematic range covered at Jefferson Lab, the access to the GPD E of the neutron which is the least constraind GPD up till now. The measurement of E, together with H, provides information on the quark total angular momentum – via the Ji's sum rule - and conveys a more complete picture of nucleon structure. The GPD E is accessed in nDVCS through the Beam Spin Asymmetry (BSA). The measurement of the BSA of nDVCS, combined with observables from pDVCS measurements, will allow to perform the flavor separation of relevant quark GPDs via linear combinations of proton and neutron GPDs. This talk will report on the experiment recently carried out at Jefferson Lab with the upgraded ~11 GeV CEBAF polarized electron beam, the Hall-B CLAS12 detector, and a liquid deuterium target. Details on the data analysis along with preliminary beam-spin asymmetries for nDVCS will be presented.
Generalized Parton Distributions (GPDs) describe the correlations between the longitudinal momentum and the transverse position of the partons inside the nucleon. They are nowadays the subject of an intense effort of research, in the perspective of understanding nucleon spin and mechanical properties.
In this talk, we present the first observation of the Timelike Compton Scattering (TCS) process, $\gamma p\to\gamma^* p^\prime\to e^+e^- p^\prime$, measured using the CLAS12 detector at Jefferson Lab, with a 10.6 GeV electron beam impinging on a liquid-hydrogen target. The initial photon polarization and the decay lepton angular asymmetries are reported in the range of timelike photon virtualities $2.25<$$Q’^{2}<9$ GeV$^2$ and the squared momentum transferred $0.1<-t<0.8$ GeV$^2$ at the average total center mass energy squared of $\bar{s}=14.5$ GeV$^2$. The polarization asymmetry, similar to the beam spin asymmetry in Deeply Virtual Compton Scattering (DVCS), projects out the imaginary part of the Compton Form Factors (CFFs, which are complex quantities linked to the GPDs) and provides a way to test the universality of Generalized Parton Distributions. The angular asymmetry of the decay leptons, on the other hand, accesses the real part of the CFF $\mathcal{H}$ which contain the D-term, a quantity directly linked to the mechanical properties of the nucleon.
Measurements of the proton's form factor ratio made with polarization transfer show a striking discrepancy relative to the ratio extracted from unpolarized elastic electron-proton scattering cross sections. One hypothesis is that the discrepancy is caused by hard two-photon exchange (TPE), a typically neglected radiative correction that may bias the two approaches differently. This hypothesis has been challenging to confirm. Theoretical estimates of TPE are model-dependent, and recent experimental determinations of TPE lacked the kinematic reach to be conclusive. The possible impact of TPE remains a cloud over our knowledge of the proton's form factors. Recently, the OLYMPUS experiment published new elastic scattering cross sections that are insensitive to the effects of TPE: specifically the average of electron-proton and positron-proton cross sections. The OLYMPUS experiment, conducted at DESY, Hamburg, measured elastic $e^-p$ and $e^+p$ scattering by detecting the scattered lepton and recoiling proton in coincidence in a large-acceptance, toroidal magnetic spectrometer. OLYMPUS was designed to measure the $e^+p$/$e^-p$ cross section ratio to isolate the effects of TPE. By exploiting the over determined kinematics of the reaction, the absolute efficiency of spectrometer could be verified, allowing cross sections to be extracted from the data. These results can help refine our knowledge of the proton's form factors, especially in the squared momentum-transfer region of 1--2 GeV$^2$, where some previous measurements are in tension.
The analysis of single transverse-spin asymmetries (SSAs) gives us tremendous insight into the internal structure of hadrons. For example, the Sivers and Collins effects in semi-inclusive deep-inelastic scattering (SIDIS), Sivers effect in Drell-Yan, and the Collins effect in electron-positron annihilation have been widely investigated over many years in order to perform 3D momentum-space tomography. In addition, observables like AN in proton-proton collisions are of interest due to their sensitivity to quark-gluon correlations. In this talk I will discuss results, and give an update on, our global fit of SSA data from SIDIS, Drell-Yan, e+e− annihilation into hadron pairs, and proton-proton collisions. I will also report on a study based on these results of the impact the EIC at Brookhaven National Lab and SoLID at Jefferson Lab will have on extracting the nucleon tensor charge. This is an important quantity that sits at the intersection of TMD studies, beyond the Standard Model physics, and lattice QCD.
We calculate single-logarithmic corrections to the small-$x$ flavor-singlet helicity evolution equations derived recently in the double-logarithmic approximation. The new single-logarithmic part of the evolution kernel sums up powers of $\alpha_s\ln(1/x)$, which are an important correction to the dominant powers of $\alpha_s\ln^2(1/x)$ summed up previously by the double-logarithmic kernel at small values of Bjorken $x$ and with $\alpha_s$ the strong coupling constant. The single-logarithmic terms arise separately from either the longitudinal or transverse momentum integrals. Consequently, the evolution equations we derive simultaneously include the small-$x$ evolution kernel and the leading-order polarized DGLAP splitting functions. We further enhance the equations by calculating the running coupling corrections to the kernel.
We present the first-ever description the world data on the $g_1^{p,n}$ structure function at small Bjorken $x$ using evolution equations in $x$ derived from first principles QCD. This is a Monte-Carlo analysis within the JAM global framework that allows us to fit all existing polarized DIS data below $x<0.1$ as well as predict future measurements of small $x$ $g_1^{p,n}$ at the EIC. This is a necessary step in determining the quark helicity PDFs and, ultimately, the quark contribution to the proton spin.
We present a new global QCD analysis of unpolarized and polarized data, using a Monte Carlo approach to simultaneously extract both the spin-averaged and helicity PDFs. We focus on the light quark sea asymmetries, including new data from the SeaQuest experiment and $W$-lepton production at RHIC. For the first time we extract a nonzero light quark sea asymmetry for the helicity PDFs through a QCD global analysis using the latest data from the STAR collaboration.
In recent years the measurements of spin and azimuthal asymmetries (SSAs) in final state hadronic distributions in semi-inclusive processes have been widely used to access the underlying Transverse Momentum Dependent (TMD) parton distributions. The detailed understanding of the orbital structure of partonic distributions, encoded in TMD PDFs has been widely recognized as one of the key objectives of the JLab 12 GeV upgrade, and a driving force behind the construction of the Electron Ion Collider.
Although the interest to TMD PDFs has grown enormously, we are still in need of fresh theoretical and phenomenological ideas, and one of the most challenging items remains the transverse momentum dependence of various observables at relatively large transverse momenta, where the non-perturbative contributions still dominate.
In this talk, we present an overview of the latest studies of hadronic multiplicities and SSAs in SIDIS, and discuss the possible sources of disagreement of experimental data with predictions based on the current TMD formalism.
Two-particle azimuthal correlation has been proposed to be one of the most direct and sensitive channels to access the nonlinear gluon dynamics in nuclei. Color Glass Condensate (CGC) predicts a suppression of back-to-back correlation in $p(d)+$A collisions compared to $p$$+$$p$ collisions. In $d+$A collisions, the double-parton scattering (DPS) can be an alternative explanation of the suppression \cite{Strikman:2010bg}. A comparison of suppression in $d+$A and $p+$A with the same kinematics provides an opportunity to study the impact of DPS. During the 2015 and 2016 RHIC runs, STAR collected data with the Forward Meson Spectrometer (FMS, 2.6 $\leq$ $\eta$ $\leq$ 4.0) in $p$$+$$p$, $p+$Al, $p$+Au and $d$+Au collisions at $\sqrt{s_{\rm {NN}}}=200$ GeV, which enables the measurements of azimuthal correlations of neutral pions in the forward region. In this talk, we will present the preliminary results on forward di-$\pi^{0}$ correlations as a function of event activity and $\pi^{0}$'s transverse momenta in $p$$+$$p$, $p+$Al and $p+$Au collisions, together with an analysis update of the same measurements in $d+$Au collisions.
\bibitem{Strikman:2010bg}
M. Strikman and W. Vogelsang, Phys. Rev. D \textbf{83}, 034029 (2011), 1009.6123.
The STAR experiment at RHIC has measured transverse single-spin asymmetries of W$^±$/$Z_0$-bosons in proton-proton collisions at a center-of-mass energy $\sqrt{s}$ = 510 GeV (2017 data). These asymmetries probe correlations between parton motion and the proton spin in the initial state which are described in terms of transverse momentum dependent parton distribution functions (TMD), in this case the Sivers function. The Sivers function is of particular theoretical interest because its process dependence can be linked to underlying kinematics, namely the gauge link structure of the scattered parton with the nucleon remnant. This means that the Sivers function is not universal and a sign change is expected between the asymmetries measured in semi-inclusive deep inelastic scattering compared to those in hadronic collisions. The new STAR preliminary results with an integrated luminosity of about 350 pb$^{-1}$ improve significantly on previous data from 2011. We will discuss details of the full reconstruction of the $W$-boson kinematics which are required for a true TMD measurement. Comparison with recent global fits will illustrate the potential impact of the new data. In addition, we will present an improved cross section measurement of $Z_0$-bosons as function of transverse momentum which now comprises an integrated luminosity of about 700 pb$^{-1}$. The STAR data are complementary to existing LHC results and will provide important input into unpolarized TMD fits.
There have been numerous results in both longitudinal and transverse spin at PHENIX. The longitudinal double spin asymmetry (A_{LL}) provides insight into the gluon helicity distribution function ({Delta}G), the contribution of gluon spin to the proton. The A_{LL} of direct photons, jets, and charged pions in polarized pp collisions at \sqrt{s} = 510 GeV have been measured, which are novel PHENIX results. The transverse single spin asymmetry (A_{N}) elucidates the transverse momentum dependent (TMD) distributions and fragmentation functions and their higher twist counterparts. A_{N} for \pi^{0}, \eta, charged pion, open heavy flavor electrons, and direct photons at midrapidity in polarized pp \sqrt{s} = 200 GeV have been measured at PHENIX. In addition, the neutron A_{N} at very forward rapidity has been measured in pA with the explicit pT and xT dependence which will provide more information about the underlying mechanisms that create the asymmetries. This talk will discuss these recent PHENIX results.
Jets encode the full evolution between the partonic state immediately following a hard-scattering interaction and the hadronic state measured in particle detectors. While only approximately 60% of the jet content corresponds to charged particles, this content can be measured with significantly higher precision than neutral particles such as photons or neutral hadrons. These measurements can be used to pose stringent tests of perturbative QCD calculations, as well as to study non-perturbative physics such as hadronization and underlying-event effects. In this talk we present an overview of recent charged-jet substructure measurements from pp collisions in ALICE, including generalized angularities, primary jet Lund plane, dynamical grooming, and angular distances between different jet axes for groomed and inclusive jets. These results provide new insights into the evolution of jets by comparing ALICE measurements to predictions from different event generators and pQCD calculations.
An important property of the strong interaction that is potentially observable in heavy-ion collisions is local parity violation which manifests itself as a charge separation along the direction of the magnetic field. This phenomenon is called the Chiral Magnetic Effect (CME). A similar effect in which the presence of a vector charge (e.g., electric charge) causes a separation of chiralities is the Chiral Separation Effect (CSE). Their coupling leads to a wave propagation of the electric charge called the Chiral Magnetic Wave (CMW), causing a charge-dependent elliptic flow.
In this talk, we present results of the charge-dependent two- and three-particle correlators as function of centrality in Xe--Xe and Pb--Pb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.44 TeV and 5.02 TeV, respectively. The charge dependence of the three-particle correlator is often employed as evidence for the CME. The interpretation of the experimental results is complicated by possible background contributions, associated with local charge conservation (LCC) coupled to elliptic flow. Comparisons with predictions from Anomalous-Viscous Fluid Dynamics simulations and a Blast-wave parametrisation that incorporates LCC are used to estimate background effects. Furthermore, these measurements combined with Monte Carlo Glauber and $\rm T_RENTo$ simulations of the magnetic field are employed to derive an upper limit on the CME contribution for the first time in Xe--Xe collisions. In addition, recent measurements of charge-dependent flow as a function of charge asymmetry are presented and their implications for observation of CMW are discussed.
Recent results from the proton-proton collision data taken by the ATLAS experiment on the charmonium production and on the B_c production and decays will be presented. The measurement of the associated production of the J/psi meson and a gauge boson, including the separation of single and double parton scattering components, will be discussed. The measurement of J/psi and psi(2S) differential cross sections will be reported as measured on the whole Run 2 dataset. The measurement of the differential ratios of the B_c+ and B+ production cross sections at 8 TeV will also be shown. New results on the B_c decays to J/psi Ds(*) final states obtained with the Run 2 data at 13 TeV will be detailed.
Information for speakers about talk's duration:
25 min slot= 20 to speak + 5 for questions
20 min slot = 17 to speak + 3 for questions
Chairs of the Sunday SM sessions:
13:00-14:35 Patricia Conde
14:45-16:00 Lina Alasfar
16:10-18:00 Pedro Silva
Chairs of the Wednesday SM sessions:
13:00-14:35 João Guimarães
14:45-16:00 João Pires
16:10-18:00 Efe Yazgan
In this talk, I will review the more important recent theoretical results in the computations and simulations of Higgs-production at the LHC.
Recent measurements from the ATLAS and CMS collaborations on Higgs boson fiducial and differential cross sections will be presented. The interpretation of results will also be shown in EFT frameworks wherever possible.
With the full Run 2 pp collision dataset collected at 13 TeV, very detailed measurements of Higgs boson properties can be performed using its decays into bosons and fermions. At the same time, the search for double-Higgs production can profit for the large integrated luminosity to provide more and more stringent limits. This talk presents measurements of Higgs boson properties using decays into bosons and fermions and their combination, including production mode cross sections and simplified template cross sections, as well as their interpretations; and the searches for non resonant di-Higgs production, as well as their combination.
One of the puzzles of the SM is the large hierarchy between the Yukawa couplings of different flavours. Yukawa couplings of the first and the second generation are constrained only very weakly so far. However, one can obtain large deviations in the Yukawa couplings in several New Physics (NP) models, such as e.g new vector-like quarks, or new Higgs bosons that couple naturally to individual fermion families. \ In this talk, I will talk about the potential bounds on the NP Higgs Yukawa couplings modification, and new $hh \bar f f$ coupling for light quarks from double-Higgs at the LHC, starting from a model independent formalism, to studying specific models. We have looked at the Higgs's' final states $ b \bar b \gamma \gamma $, and the relevant experimental cuts to reduce backgrounds and estimated the potential exclusion bounds for light quark couplings with the Higgs. I will also talk about the potential for double Higgs production to probe non-linearity between Yukawa and $hh \bar f f$ couplings
We present a global interpretation of Higgs, diboson, and top quark production and decay measurements from the LHC in the framework of the Standard Model Effective Field Theory (SMEFT) at dimension six. We constrain simultaneously 36 independent directions in its parameter space, and compare the outcome of the global analysis with that from individual and two-parameter fits. Our results are obtained by means of state-of the-art theoretical calculations for the SM and the EFT cross-sections, and account for both linear and quadratic corrections in the $1/\Lambda^2$ expansion. We demonstrate how the inclusion of NLO QCD and quadratic EFT effects is instrumental to accurately map the posterior distributions associated to the fitted Wilson coefficients. We assess the interplay and complementarity between the top quark, Higgs, and diboson measurements, deploy a variety of statistical estimators to quantify the impact of each dataset in the parameter space, and carry out fits in BSM-inspired scenarios such as the top-philic model. Our results represent a stepping stone in the ongoing program of model independent searches at the LHC from precision measurements, and pave the way towards yet more global SMEFT interpretations extended to other high-$p_T$ processes as well as to low-energy observables.
Exotic and rare decays of the Higgs boson provide a unique window for the discovery of new physics, as the Higgs boson may couple to hidden-sector states that do not interact under the Standard Model gauge transformations. Models predicting exotic Higgs boson decays to pseudoscalars can explain the galactic centre gamma-ray excess, if the additional pseudoscalar acts as the dark matter mediator. This talk presents recent searches for decays of the 125 GeV Higgs boson to new particles, and searches for rare decays of the Higgs boson where enhanced rates would be a sign of new physics. These searches use LHC collision data at sqrt(s) = 13 TeV collected by the ATLAS and CMS experiments in Run 2.
Higgs-pair production is one of the targets of the high-luminosity LHC and of future hadron colliders, as it allows for a direct probe of the trilinear Higgs coupling and hence of the mechanism behind electroweak symmetry breaking. This talk will present the impact of the full next-to-leading order QCD corrections to Higgs-pair production via gluon fusion, the main production mechanism at hadron colliders, in the Standard Model and in Two-Higgs-Doublet models of type II. The uncertainties due to the top-mass scale and scheme choice will be discussed.
Double Higgs production at the LHC
...
Higgs factories based on e+e- colliders have the potential to measure the complete profile of the Higgs boson at a level of precision that goes qualitatively beyond the expected capabilities of the LHC. This talk will review the program of Higgs boson coupling measurements expected from the International Linear Collider, including the most recent updates. These measurements span the range of e+e- center-of-mass energies from 250 GeV to 1 TeV and include precision measurements of the top quark Yukawa coupling and the Higgs self-coupling.
(On behalf of the ILC International Development Team Detector & Physics Speakers Bureau)
LEP precision on electroweak measurements was sufficient not to hamper the extraction of Higgs couplings at the LHC. But the foreseen permille-level Higgs measurements at future lepton colliders might suffer from parametric electroweak uncertainties in the absence of a dedicated electroweak program. We perform a joint, complete and consistent effective-field-theory analysis of Higgs and electroweak processes. The full electroweak-sector dependence of the $e^{+}e^{−} \rightarrow WW$ production process is notably accounted for, using statistically optimal observables. Up-to-date HL-LHC projections are combined with CEPC, FCC-ee, ILC and CLIC ones. For circular colliders, our results demonstrate the importance of a new $Z$-pole program for the robust extraction of Higgs couplings. At linear colliders, we show how exploiting multiple polarizations and centre-of-mass energies is crucial to mitigate contaminations from electroweak parameter uncertainties on the Higgs physics program. We also investigate the potential of alternative electroweak measurements to compensate for the lack of direct $Z$-pole run, considering, for instance, radiative return to these energies. Conversely, we find that Higgs measurements at linear colliders could improve our knowledge of the $Z$ couplings to electrons. Our results can be found at: arXiv:1907.04311
Single boson production overview (W, Z, ४) at the LHC
Information for speakers about talk's duration:
25 min slot= 20 to speak + 5 for questions
20 min slot = 17 to speak + 3 for questions
The Mu2e experiment aims to measure the charged-lepton flavour violating (CLFV) neutrino-less conversion of a negative muon into an electron in the field of an aluminum nucleus. The conversion process results in a monochromatic electron with an energy slightly below the muon rest mass (104.97 MeV). The Mu2e goal is to improve the world’s best limit by SINDRUM II of four orders of magnitude and reach a single event sensitivity of 3.0 x 10^{-17} on the conversion rate with respect to the muon capture rate.
In many Beyond the Standard Model (BSM) scenarios, rates for CLFV processes are within the reach of the next generation experiments and their searches have a sensitivity to new physics that exceeds the LHC reach bringing the reach of new mass scale up to 10^4 TeV. In this context, indirect measurements of CLFV could provide crucial evidence for new physics.
Mu2e exploits a very intense pulsed negative muon beam on an aluminum target for a total number of 10^{18} stopped muons. Production and transport of the muons is performed with a complex and sophisticated magnetic system composed by a production, a transport and a detector solenoid.
The improvement with respect to previous conversion experiments is based on four main elements: the muon beam intensity, the beam structure layout, the extinction of out of time particles and the precise electron identification in the detector solenoid. The conversion electron will be reconstructed and separated from the Decay in Orbit (DIO) background by exploiting the very high resolution (120 keV) tracking system based on straw technology. The crystal calorimeter system will confirm that the candidates are indeed electrons by performing a powerful mu/e rejection while granting a tracking independent HLT filter. A Cosmic Ray Veto system will surround the entire detector solenoid and contribute to minimize the backgrounds due to cosmic muons.
The Belle II experiment is a substantial upgrade of the Belle detector and will operate
at the SuperKEKB energy-asymmetric e+e− collider. The design luminosity of the machine
is 8 × 1035 cm−2s−1 and the Belle II experiment aims to record 50 ab−1 of data, a factor
of 50 more than its predecessor. From February to July 2018, the machine has completed a
commissioning run and main operation of SuperKEKB has started in March2019. Belle II has
a broad τ physics program, in particular in searches for lepton flavour and lepton number
violations (LFV and LNV), benefiting from the large cross section of the pair wise τ
lepton production in e+e− collisions. We expect that after 5 years of data taking, Belle II
will be able to reduce the upper limits on LF and LN violating τ decays by an order of
magnitude. Any experimental observation of LFV or LNV in τ decays constitutes an unambiguous
sign of physics beyond the Standard Model, offering the opportunity to probe the underlying
New Physics. In this talk we will review the τ lepton physics program of Belle II.
Within the Standard Model Effective Field Theory framework, with operators up to dimension 6, we perform a model-independent analysis of the lepton-flavour-violating processes involving tau leptons. Namely, we study hadronic tau decays and $\ell$-$\tau$ conversion in nuclei, with $\ell = e,\mu$. Based on available experimental limits, we establish constraints on the Wilson coefficients of the operators contributing to these processes. The translation of these constraints into the most general leptoquark framework is also considered. Our work paves the way to extract the related information from Belle II and foreseen future experiments.
The measurement of a permanent electric dipole moment of the neutron (nEDM), as a CP-violating observable, is one of the main priorities at the low energy frontier of particle physics. A discovery or a highly improved constraint could contribute to our understanding of the baryon asymmetry of the universe. Our international collaboration obtained a new limit on the nEDM with an apparatus connected to the UCN source of the Paul Scherrer Institut in Switzerland. This experiment was based on the Ramsey method of separated oscillatory fields in vacuum and at room temperature. An important gain compared to previous experiments was a much-advanced control of the homogeneity and stability of the magnetic field. To this end, the method of mercury co-magnetometry was further optimized, and cesium magnetometers were employed to suppress field gradients of higher orders. A blinding scheme in two steps was developed in order to exclude any bias in the work of two distinct analysis groups. In this talk, we present our new result and the steps which led to this novel constraint on the nEDM.
New physics models with additional CP violation sources are currently being constrained by searches for electric dipole moments (EDMs). Using the stringent limits on their chromo-EDMs, new bounds on the EDM of charm and bottom quarks will be derived. The new limits improve the previous ones by about three orders of magnitude. The implications for different Standard Model extensions will be discussed.
The neutron Electric Dipole Moment (EDM) has always attracted interest as a promising channel for finding new physics. The existence of a neutron EDM would violate CP symmetry given the CPT conservation. This new source of CP violation could explain the baryon asymmetry of the universe. The BeamEDM experiment aims to measure the neutron EDM using a novel technique which overcomes the previous systematic limitation of neutron beam experiments, the relativistic vxE effect. The experiment exploits the time-of-flight technique with a pulsed cold neutron beam which allows to distinguish between time dependent and time independent effects such as the EDM. A proof-of-principle apparatus has been developed to perform preliminary measurements for the future full-scale experiment intended for the European Spallation Source in Sweden.
In this presentation the details of the experimental setup together with the latest results from the data taking in August 2020 at the Institut Laue-Langevin in France will be presented.
Searches for permanent electric dipole moments (EDMs) provide important results to constrain model parameters and promising experiments to potentially reveal beyond Standard Model (SM) physics. A non-zero EDM is a direct manifestation of time-reversal (T) violation, and, equivalently, violation of the combined operation of charge-conjugation (C) and parity inversion (P). Identifying new sources of CP violation can help to solve fundamental puzzles of the SM, e.g. the observed baryon-asymmetry in the Universe.
The PanEDM experiment’s goal is to measure the EDM of the neutron with a sensitivity at least one order of magnitude below the current best limit of d$_n$<1.8e-26 ecm (90% C.L.). Located at the new ultra-cold neutron (UCN) source SuperSUN at ILL PanEDM will greatly benefit from high UCN densities with UCN energies below 80 neV. A statistical neutron EDM sensitivity of 3.8e-27 ecm is expected within 100 measurement days with SuperSUN phase-I. With future phase-II improvements in SuperSUN and the PanEDM apparatus an ultimate statistical sensitivity of 7.9e-28 ecm is anticipated.
The already commissioned passive magnetic shield provides highly stable magnetic fields with drifts <10fT over 250s and magnetic field gradient drifts <10fT/m/s, strongly suppressing major systematic effects. Other subsystems addressing systematic effects are being commissioned, e.g. external Hg magnetometer cells, an all-optical Cs magnetometer array and the high-voltage system including a leakage current monitor.
In this presentation I will give an overview of ILL’s new UCN source SuperSUN, the PanEDM experiment and its main components and a status report on recent progress including results from ongoing commissioning of SuperSUN.
Molecular spectroscopy represents a unique tool in the search for physics beyond the Standard Model and exploration of the fundamental forces of nature. Compared to atoms, molecules can offer more than five orders of magnitude enhanced sensitivity to violations of fundamental symmetries, testing energy scales beyond hundreds of TeV. These effects are further enhanced in radioactive molecules, which are particularly sensitive to nuclear parity violating (P-odd) and time-reversal violating (T-odd) effects. A promising candidate for this kind of studies is radium monofluoride (RaF). Containing octupole-deformed nuclei, this molecule is expected to show a high sensitivity for the electron interaction with the P-odd nuclear anapole moment as well as with the P- and T-odd nuclear Schiff and magnetic quadrupole moments. In addition, being laser coolable, RaF is suitable for high-precision studies. In this talk I will present the latest results obtained from a series of laser spectroscopy experiments performed on short-lived RaF isotopologues, at ISOLDE facility at CERN. I will first describe a measurement of the isotope shift of five RaF isotopologues, $^{223-226,228}$RaF. This shows the particularly high sensitivity of radium monofluoride to nuclear size effects, offering a stringent test of models describing the electronic density within the radium nucleus. I will then show preliminary results from a high-resolution laser spectroscopy of $^{223}$RaF and $^{226}$RaF. Rotational and hyperfine constants of these two isotopologues will be presented. These results represent the first of their kind performed on radioactive, short-lived molecules, opening the way for precision studies and new physics searches in these systems.
We have made recent progress in studying the short-distance properties of the hadronic light-by-light contribution to the muon $g-2$. The intermediate and short-distance part is a major contributor to the error of the hteoretical prediction, see the white paper [arxiv:2006.04822, Physics Reports 887 (2020) 1-166]. We have recently shown that the massless quark-loop is the first term in a systematic expansion at short-distance [arxiv:1908.03331, Phys.Lett. B798 (2019) 134994].This result already helped in the white paper in bringing down the error. Since then we have shown that both nonperturbative [arxiv:2008.13487, JHEP 10 (2020) 203] and the perturbative corrections [arxiv:2101.09169, JHEP 04 (2021) 240] are under control. The talk will describe these developments and how they fit in the total theopretical prediction for the muon $g-2$.
The LUXE experiment (LASER Und XFEL Experiment) is a new experiment in planning at DESY Hamburg using the electron beam of the European XFEL. LUXE is intended to study collisions between a high-intensity optical LASER and 16.5 GeV electrons from the XFEL electron beam, as well as collisions between the optical LASER and high-energy secondary photons. The physics objective of LUXE are processes of Quantum Electrodynamics (QED) at the strong-field frontier, where the electromagnetic field of the LASER is above the Schwinger limit. In this regime, QED is non-perturbative. This manifests itself in the creation of physical electron-positron pairs from the QED vacuum, similar to Hawking radiation from black holes. LUXE intends to measure the positron production rate in an unprecedented LASER intensity regime. An overview of the LUXE experimental setup and its challenges will be given, followed by a discussion of the expected physics reach in the context of testing QED in the non-perturbative regime.
The Cosmic Axion Spin Precession Experiments (CASPEr) search for ultralight axion-like dark matter. CASPEr-e is sensitive to the time-varying nuclear electric dipole moment, induced by the electric-dipole moment (EDM) coupling $g_d$. The detection scheme is based on a precision measurement of
$^{207}$Pb solid-state nuclear magnetic resonance in a polarized ferroelectric crystal. We calibrated the detector and characterized the excitation spectrum and relaxation parameters of the nuclear spin ensemble with pulsed magnetic resonance measurements in a 4.4 T magnetic field. We swept the magnetic field near this value and searched for axion-like dark matter with Compton frequency within a 1 MHz band centered at 39.65 MHz. Our measurements place the upper bound $|g_d|<9.5\times10^{-4}\,\text{GeV}^{-2}$ (95% confidence level) in this frequency range. This constraint corresponds to an upper bound of $1.0\times 10^{-21}\,\text{e}\cdot\text{cm}$ on the amplitude of oscillations of the neutron electric dipole moment, and $4.3\times 10^{-6}$ on the amplitude of oscillations of CP-violating $\theta$ parameter of quantum chromodynamics. Our results demonstrate the feasibility of using solid-state nuclear magnetic resonance to search for axion-like dark matter in the nano-electronvolt mass range.
Videos available till December 31, 2021
Standard Model at the TeV Scale: https://youtu.be/B1I5Hr1HGm8
DM and Cosmology: https://youtu.be/5qRh-Q61VZo
Neutrino Physics: https://youtu.be/m5GiFfZvRu8
Flavour physics: https://youtu.be/dQzSUsajA9Q
Tests of symmetries: https://youtu.be/I1eU25BlW-8
Hadron spectroscopy: https://youtu.be/r91FSKpvuSA
QCD, spin, chiral dynamics: https://youtu.be/Q4azmww01QQ
Nuclear and Particle Astrophysics: https://youtu.be/WJfThcZf-Xg
EIC & Hot and dense matter: https://youtu.be/JhPZWd5caOc
Hadrons in medium: https://youtu.be/OkNv_ls-aw0
Accelerators&Detectors, Data Science, Gravitational Waves, Best Posters: https://youtu.be/chr0o472KkA
We present in this contribution an overview of the latest Higgs results published by the ATLAS and CMS collaborations. The focus will be on analyses considering the whole Run 2 dataset, showing measurements of the Higgs boson mass and inclusive, fiducial, and differential cross-section measurements in the main decay channels and searches in more challenging phase spaces. Finally, a review of the newest searches for double Higgs production at the LHC is presented.
Videos available till December 31, 2021
Standard Model at the TeV Scale: https://youtu.be/B1I5Hr1HGm8
DM and Cosmology: https://youtu.be/5qRh-Q61VZo
Neutrino Physics: https://youtu.be/m5GiFfZvRu8
Flavour physics: https://youtu.be/dQzSUsajA9Q
Tests of symmetries: https://youtu.be/I1eU25BlW-8
Hadron spectroscopy: https://youtu.be/r91FSKpvuSA
QCD, spin, chiral dynamics: https://youtu.be/Q4azmww01QQ
Nuclear and Particle Astrophysics: https://youtu.be/WJfThcZf-Xg
EIC & Hot and dense matter: https://youtu.be/JhPZWd5caOc
Hadrons in medium: https://youtu.be/OkNv_ls-aw0
Accelerators&Detectors, Data Science, Gravitational Waves, Best Posters: https://youtu.be/chr0o472KkA
Videos available till December 31, 2021
Standard Model at the TeV Scale: https://youtu.be/B1I5Hr1HGm8
DM and Cosmology: https://youtu.be/5qRh-Q61VZo
Neutrino Physics: https://youtu.be/m5GiFfZvRu8
Flavour physics: https://youtu.be/dQzSUsajA9Q
Tests of symmetries: https://youtu.be/I1eU25BlW-8
Hadron spectroscopy: https://youtu.be/r91FSKpvuSA
QCD, spin, chiral dynamics: https://youtu.be/Q4azmww01QQ
Nuclear and Particle Astrophysics: https://youtu.be/WJfThcZf-Xg
EIC & Hot and dense matter: https://youtu.be/JhPZWd5caOc
Hadrons in medium: https://youtu.be/OkNv_ls-aw0
Accelerators&Detectors, Data Science, Gravitational Waves, Best Posters: https://youtu.be/chr0o472KkA
Hyperons provide an unique avenue to study the strong interaction in baryon structure. Due to their limited life time, the production in e+e- annihilations is the only viable way to obtain information on the hyperon structure and internal dynamics through their electromagnetic form factors. With the unique data sets obtained by the BESIII collaboration, the pair production cross sections for Lambda, Sigma, Xi, and Lambda_c are studied from threshold, where some abnormal threshold effects are observed. Using the self-analyzing weak decays of the Lambda and Lambda_c, the relative phase between the electric and magnetic form factors is measured. In this presentation the latest results at BESIII are discussed.
The muon campus program at Fermilab includes the Mu2e experiment that will search for charged-lepton flavor violating processes where a negative muon converts into an electron in the field of an aluminum nucleus. The conversion process results in a monochromatic electron with an energy of 104.97 MeV, slightly below the muon rest mass. The goal of the experiment is to improve the previous upper limit by four orders of magnitude.
Mu2e’s Trigger and Data Acquisition System (TDAQ) uses {\it otsdaq} as its solution. Developed at Fermilab, {\it otsdaq} uses the {\it artdaq} DAQ framework and {\it art} analysis framework, under-the-hood, for event transfer, filtering, and processing.
{\it otsdaq} is an online DAQ software suite with a focus on flexibility and scalability. It provides a multi-user, web-based interface, accessible through a web browser.
A Detector Control System (DCS) for monitoring, controlling, alarming, and archiving has been developed using EPICS (Experimental Physics and Industrial Control System) open-source Platform. The DCS System has also been integrated into {\it otsdaq}, providing a multi-user GUI, web-based control, and monitoring dashboard that communicates with EPICS using an interface specifically designed and developed.
NA61/SHINE is a fixed-target experiment located at CERN Super Proton Synchrotron (SPS). The development of new beam position detectors is part of the ongoing upgrade of the detector system.
Two types of detectors have been manufactured and tested. The first one is a scintillating fibers detector with photo-multiplayer as a readout. The scintillating fibers detector consists of two ribbons, which are arranged perpendicularly to each other. Each ribbon is made of two layers of 250 μm diameter fibers. The grouping of fibers method was used, which allows using of a single multichannel photo-multiplayer for one detector.
The second type of detector is based on the single-sided silicon strip detector (SSD). In this project, Si strips produced by Hamamatsu (S13804) were used, where each strip has a width equal to 80 μm.
The developed detectors must meet several requirements: should work efficiently with proton and lead beams with beam intensity on the level of 100 kHz, the detector's material on the beamline should be minimized, the detectors should be able to determine the position of X and Y hit of each beam particle with maximum possible accuracy.
During the poster session I will present the results of our work.
A new era of hadron collisions will start around 2027 with the High-Luminosity LHC, that will allow to collect ten times more data that what has been collected since 10 years at LHC. This is at the price of higher instantaneous luminosity and higher number of collisions per bunch crossing.
In order to withstand the high expected radiation doses, the ATLAS Liquid Argon Calorimeter readout electronics will be upgraded.
The electronic readout chain is made of 4 main parts.
The new front-end board will allow to amplify, shape and digitise on two gains the ionisation calorimeter signal over a dynamic range of 16 bits and 11 bit precision. Low noise below Minimum Ionising Particle (MIP), i.e below 120 nA for 45 ns peaking time, and maximum non-linearity of two per mil are required. Custom low noise preamplifier and shaper are being developed to meet these requirements using 65 nm and 130 nm CMOS technologies. They should be stable under irradiation until 1.4kGy (TID) and 4.1x10^13 new/cm^2 (NIEL). Two concurrents preamp-shaper ASICs have been developed and the best one in term of noise has been chosen. The test results of the new version of this ASIC will be presented. A new ADC chip prototype has been also submitted in June. Integration tests of the different components (including lpGBT links developed by CERN) on a 32-channels front-end board are ongoing, and results of this integration will be also shown.
The new calibration board will allow the precise calibration of all 128000 channels of the calorimeter over a 16 bits dynamic range. A non-linearity of one per mil and non-uniformity between channels of 0.25% with a pulse rise time smaller than 1ns should be achieved. In addition, the custom calibration ASICs should be stable under irradiation with same levels as preamp-shaper and ADC chips. The HV SOI CMOS XFAB 180nm technology is used for the pulser ASIC, while the TSMC 130 nm technology is now used for the DAC part. During second prototype testing, it was found that the DAC part of the calibration system, inserted previously with the pulser in XFAB 180nm technology, was not rad-hard, already after 0.5 kGy. This is why a third version has been designed overcoming this issue, and all results will be presented.
The data are sent off-detector at 40 MHz where FPGAs connected through high-speed links will perform energy and time reconstruction through the application of corrections and digital filtering. The off-detector electronics receive 345 Tbps from front-end readout, which require 33000 links at 10 Gbps. For the first time, online machine learning technics are used in the FPGAs in order to better filter the data. The first test results of the signal processing board will be shown.
Reduced data are then sent with low latency to the first level trigger, while the full data are buffered until the reception of trigger accept signals. The data-processing, control and timing functions are realized by dedicated boards connected through ATCA crates. Design status of this timing boards will be shown too.
Karishma Dhanmeher – for the BRAND Collaboration
Institute of Physics, Jagiellonian University, Kraków, Poland,
Institute of Nuclear Physics, Polish Academy of Sciences, Kraków, Poland,
Institute of Nuclear and Radiation Physics, KU Leuven, Belgium,
Institut Laue-Langevin, Grenoble, France,
Department of Chemistry - TRIGA site, Johannes Gutenberg University Mainz, Mainz,
Germany
Department of Physics and Astronomy, North Carolina State University, Raleigh, USA
Abstract:
The BRAND experiment aims at the search of Beyond Standard Model (BSM)
physics via measurement of exotic components of weak interaction. For this
purpose, eleven correlation coefficients of neutron beta decay will be measured
simultaneously. Seven of them: H, L, N, R, S, U and V, are sensitive to the
transverse polarization of electrons from free neutron decay. The correlation
coefficients will be derived using Mott polarimetry and completely determined
kinematics of products from the polarized neutron beta decay. For this aim the
beam of cold polarized neutrons available in PF1B areal at ILL, Grenoble will
be utilized.
The electron detection system features both the tracking and energy measure-
ment capability as well as the Mott polarimetry for determination of the electron
spin orientation. The 3D tracking is performed with a low density, helium based
drift chamber of a hexagonal cell structure which is optimized for beta particles.
The Mott polarimeter is an integral part of the tracker. It consists of a thin Pb
foil installed inside, the drift chamber and two plastic scintillators, providing
trigger and scattered electron energy measurement.
The results of the first pilot run of the BRAND experiment performed in Septem-
ber ’20 will be reported with emphasis on the description and the performance
of the electron detection system and the Mott polarimeter.
CYGNO is part of the CYGNUS international proto-collaboration for the development of a distributed Galactic Nuclear Recoil Observatory for directional Dark Matter search at low WIMP masses (1-10 GeV/c2) and coherent neutrino scattering measurement. CYGNO is developing a gaseous Time Projection Chamber (TPC), which will be hosted at Laboratori Nazionali del Gran Sasso, Italy. The CYGNO-TPC will rely on a triple Gas Electron Multiplier (GEM) stack for charge multiplication and electroluminescence (EL) production, operating at room temperature and atmospheric pressure. The EL will be collected with a high resolution scientific camera for particle identification and 2D track reconstruction, with the aim of discriminating nuclear recoils and their direction.
To probe the middle energy and mass range of WIMPs (GeV), having a low mass target is essential, hence He will be the main component of the CYGNO-TPC. The addition of CF$_4$ is also fundamental as it increases gas scintillation and sensitivity to Spin Dependent WIMP-Nucleon Coupling. To further improve the tracking capabilities of the gas mixture (such as electron diffusion and drift velocity), the addition of isobutane and other gases with high H-content is currently under consideration.
This work aims at determining how the addition of small percentages of isobutane to the He-CF$_4$ (60/40) base mixture influences the EL yield, charge gain and corresponding energy resolution. The detector, operated in continuous-flow mode, was irradiated with low-energy x-rays (5.9-keV) and a Large Area Avalanche Photodiode (LAAPD) was used to readout the EL produced in the avalanches of a single GEM. Increasing concentrations of isobutane, from 1% to 5%, were added to the base mixture of He-CF$_4$ (60/40), continuously flowing at 4 L/h.
Our results show that the number of avalanche electrons increases with the addition of isobutane, with a 2.7-fold increase for 5% isobutane content relatively to 0%. The energy resolution of the charge signals is independent of the isobutane content and around 12 % (FWHM) for all mixtures. The EL yield decreases with increasing concentration of isobutane. Although a 7.9-decrease in the number of EL photons emitted per avalanche electron was measured for 5% isobutane relative to 0%, there was only a 2.8-fold decrease in the total number of emitted EL photons. The energy resolution of the EL signals was around 20%, showing a slight degradation with increasing isobutane content, which we attribute to low statistics.
These results show that isobutane does not compromise the total amount of EL photons, while maintaining the energy resolution of the base mixture unchanged and is therefore a good option to study for possible applications in the CYGNO-TPC.
The physical properties of neutrons make them an excellent probe for the investigation of matter in different scientific fields, such as physics, chemistry and biology as well as for specific medical and industrial applications. Along with neutron imaging, a variety of techniques use neutron irradiation on a sample to characterize it, such as neutron diffraction, reflectometry, spectroscopy, and small angle scattering. All these have a common need: the detection of neutrons that are transmitted or scattered by the sample. Because neutrons are electrically neutral, their detection is usually achieved via nuclear capture reactions, in which the neutron is absorbed by the nucleus of an atom, which becomes unstable and decays into two highly ionizing charged particles. These reactions only occur with significant cross-section for a few isotopes and the ones with practical interest for detection applications are, by decreasing cross-section, 3He, 10B and 6Li. Until recent years, proportional counters filled with 3He gas were considered the golden standard for neutron detection, due to their high efficiency, good gamma-ray discrimination, and non-toxicity. However, when a severe shortage of this gas was acknowledged, prices skyrocketed and heavy acquisition restrictions were implemented, which urged for the pursue of alternative technologies. One additional motivation was given by the fact that 3He detectors were already at the limit of their performance capabilities, namely regarding counting rate and position resolution, which fell short of the requirements of instruments in new neutron facilities such as the European Spallation Source (ESS), that will provide a neutron beam up to one hundred times brighter than currently available in any other existing facility.
Consequently, over the last decade, a great deal of effort and investment was put into the development of 3He-free neutron detectors, and for a wide range of applications, gaseous detectors that rely on the 10B nuclear capture reaction are the most promising. Because elemental boron is a solid at STP conditions, these detectors employ a thin coating of boron or other boron-containing material, such as boron carbide (B4C), surrounded by a proportional gas for charge amplification. These materials are not self-supporting, hence are generally deposited directly on the inner walls of the detector or in aluminium substrates that are then inserted into it.
Due to momentum and energy conservation, the reaction products of the 10B neutron capture (an alpha particle and a 7Li nucleus) are emitted in the same line of action, in opposite directions. Consequently, in conventional boron coated detectors, for each neutron capture, only one of the reaction products can travel towards the gas to generate a signal in the detector, while the other is absorbed by the boron layer or the substrate. Furthermore, depending on the depth in which the nuclear capture occurs and the consequent energy lost to collisions inside the boron layer, the range of the 7Li and alpha particles in conventional proportional gases at atmospheric pressure can extend from virtually zero to about 10 millimetres. This intrinsically limits the spatial resolution of such detectors, which generally calculate the centre of gravity from many neutron detections to estimate with greater precision the neutron capture site. While this position uncertainty can be reduced by increasing gas pressure, which results in shorter particle travel ranges, this poses a mechanical challenge that requires the use of thicker entrance windows, which in term increases the probability of neutrons being scattered or absorbed before reaching the sensitive region of the detector.
Although the range of the 7Li and 4He fission fragments from the neutron capture reaction in solids is only of a few microns, current conventional gaseous neutron detectors based on 10B adopt detection layers with a combined thickness of converter and substrate with, at least hundreds of microns, most frequently extending to many millimetres. In this work, we propose an alternative approach that aims at simultaneously detecting both secondary products of neutron capture reactions which can be achieved if thin enough converter and substrate layers are deployed. By using independent readout systems to detect each particle that emerges on opposite sides of the conversion layer, and crossing the information from these two signals, it is possible to reconstruct the neutron interaction site with greater precision than using the centre of gravity approach of conventional detectors, while also requiring less statistic.
Monte Carlo simulations with GEANT4 were developed to compare the position reconstruction uncertainty of a state-of-the-art boron detector with the novel coincidence detector. An incident point thermal neutron beam at a fixed position was considered, and the estimation of the neutron interaction site for each detected neutron was achieved by weighting the energy deposited along the trajectory of each particle in the x-projection of the track. For the same neutron exposure, the simulation results show an improvement of intrinsic spatial resolution (FWHM) by a factor of approximately 8.
The observation of neutrons converting to antineutrons and/or sterile neutrons would demonstrate Baryon Number Violation (BNV) for the first time. BNV is an essential condition needed to produce the matter/anti-matter asymmetry in the universe and appears in a number of theories beyond the Standard Model. The existence of sterile neutrons would address the issue of a possible dark sector of particles. The HIBEAM/NNBAR project is a proposed series of experiments for the European Spallation Source (ESS) that can open up a discovery window for BNV by observing free neutrons transforming to antineutrons and/or sterile neutrons. A series of competitive searches are planned with an ultimate improvement in sensitivity of three orders of magnitude compared with the previous free neutron to anti-neutron search at Institut Laue-Langevin. This talk describes the HIBEAM/NNBAR experiment. The motivation for the experiment and theories predicting neutron conversions are described, followed by a description of the ESS and those ESS facilities which can be exploited for the experiment. The set-ups and sensitivities of the neutron conversion searches are shown. Special focus is placed on the annihilation detector which would use a Time Projection Chamber and calorimeter system exploiting scintillators and lead-glass. Geant-based simulations of the annihilation signature within a detector are shown and compared with background predictions. Finally, it is also shown how the program of work benefits from important but lower sensitivity searches ongoing by the Oak Ridge National Laboratory and being performed by many of the same collaborators as those on HIBEAM/NNBAR. Although it is a dedicated particle physics experiment, HIBEAM/NNBAR is a multi-disciplinary milieu, bringing together experts in neutronics, magnetics, detector design, and data analysis.
Xenon scintillation has been extensively used in recent particle physics experiments. However, information on primary scintillation yield is still scarce and dispersed. The mean energy required to produce a VUV scintillation photon (Wsc) in gaseous xenon has been measured in the range of 30-120 eV. Lower Wsc-values are often reported for alpha particles compared to electrons produced by gamma or x-rays, being this difference still not fully understood.
We carried out a systematic study on the absolute primary scintillation yield in xenon at 1.2 bar, using a Gas Proportional Scintillation Counter. A simulation model of the detector's geometric efficiency was benchmarked through the primary and secondary scintillation produced at different distances from the photosensor. Wsc-values were obtained for gamma- and x-rays with energies in the range from 5.9-60 keV and for 2-MeV alpha particles. No significant differences were found between alpha particles and electrons.
The CSES (China Seismo-Electromagnetic Satellite) is a multi-instrumental scientific space program devoted to study the near-Earth electromagnetic, plasma and particle environment to understand the seismo-associated disturbances in the ionosphere-magnetosphere transition zone. In particular, the mission aims at confirming the existence of possible temporal correlations between the occurrence of medium and large magnitude earthquakes and the observation in space of electromagnetic perturbations, plasma variations and precipitation of bursts of high-energy charged particles from the inner Van Allen belt.
The first satellite (CSES-01) was launched in 2018, while the second one (CSES-02) is currently under development and its launch is expected by 2022. One of the instruments on board the satellites is a particle detector (HEPD-02, High-energy Particle Detector). This high-precision particle detector measures electrons in the energy range between 3 and 100 MeV, protons between 30 and 200 MeV, as well as light nuclei in the MeV energy window.
The HEPD-02 detector will be composed of a tracker made of Monolithic Active Pixel Sensors and a double layer of crossed plastic scintillators for trigger. The actual calorimeter will be constituted by a tower of plastic scintillator and two-segmented planes of inorganic LYSO crystals. The calorimeter is surrounded by five scintillator planes used as a veto system.
This contribution describes the new architecture and the main characteristics of HEPD-02, with a focus on the choices made to meet the challenging scientific objectives of the mission.
The Mu2e experiment at Fermi National Accelerator Laboratory (Batavia, Illinois, USA) searches for the charged-lepton flavor violating neutrino-less conversion of a negative muon into an electron in the field of an aluminum nucleus. The dynamics of such a process is well modelled by a two-body decay, resulting in a mono-energetic electron with energy slightly below the muon rest mass (104.967 MeV). Mu2e will reach a single event sensitivity of about 3x10−17 that corresponds to four orders of magnitude improvement with respect to the current best limit.
The calorimeter plays an important role to provide excellent particle identification capabilities and an online trigger filter while aiding the track reconstruction capabilities, asking for 10% energy resolution and 500 ps timing resolution for 100 Mev electrons. It consists of two disks, each one made by 674 un-doped CsI crystals, read out by two large area UV-extended SiPMs. In order to match the requirements of reliability, a fast and stable response, high resolution and radiation hardness (100 krad, 10^12 n/cm^2) that are needed to operate inside the evacuated bore of a long solenoid (providing 1 T magnetic field) and in the presence of a really harsh radiation environment, fast and radiation hard analog and digital electronics has been developed. To support these crystals, cool the SiPMs and support and cool the electronics, a sophisticated mechanical and cooling system has been also designed and realized.
In this paper, we present the status of construction and QC performed on the produced crystals and photosensors, the development of the rad-hard electronics and the most important results of the irradiation tests done on the different components. Production of electronics is also started and we summarize the QC in progress on the analog electronics and on the integrated SIPM+FEE units. Construction of the mechanical parts are also well underway. Status and plans for the final assembly are also described.
Moreover, a large calorimeter prototype (dubbed Module-0) has been tested with an electron beam between 60 and 120 MeV at different impact angles and the obtained results are summarized. Finally, a full vertical slice test with the final electronics is in progress on Module-0 at the Frascati Cosmic Rays test setup. First calibration results are shown.
In this contribution, recent results on the sensitivity of future lepton colliders to WIMP dark matter (DM) pair production are reviewed. Considered are processes with mono-photon signature, when DM production is accompanied by a hard photon emission from the initial state radiation, through which the process can be identified.
Corresponding study was performed with full detector simulation for the International Large Detector (ILD) concept at the International Linear Collider (ILC), for a centre-of-mass energy of 500 GeV. In the effective field theory (EFT) approach scales of up to 3 TeV can be tested for different operator types and DM masses almost up to half the collision energy. The sensitivity benefits from the polarised beams, which can reduce the main SM background from neutrino pair production substantially. Systematic uncertainties are also significantly reduced when combining data with different polarisation configurations.
Similar study was performed to investigate potential for detecting DM at the Compact Linear Collider (CLIC) running at 3 TeV. When considering the ratio of the mono-photon energy distributions for left-handed and right-handed polarised electron beams, most systematic uncertainties cancel out, resulting in the best limits on the DM pair-production cross section. These limits can be then translated, using simplified DM models, into exclusion limits for DM and mediator
masses for fixed values of the mediator couplings to SM and DM particles.
Finally, pair-production of DM particles at the ILC and CLIC was also studied for scenarios with small mediator masses and small mediator couplings to the SM particles. Limits on the production cross section can be extracted from the two-dimensional distributions of the reconstructed mono-photon events. Limits on the mediator coupling to electrons are presented for a wide range of mediator masses and widths. For mediator masses up to the centre-of-mass energy of the collider,
limits expected from the mono-photon analysis are more stringent than the limits from direct resonance search in SM decay channels.
The International Linear Collider offers a number of unique opportunities for searches for dark matter and dark sector particles. The collider program will offer important capabilities, but also, the ILC will enable new fixed-target experiments using the high-energy electron and positron beams, both beam dump experiments and dedicated experiments using single beams. This talk will describe the expectations for these programs, which address all of the possible dark sector portals.?
(on behalf of the ILC International Development Team Speakers Bureau)
A new reconstruction method to explore the low mass region in the associated production of top-quark pairs ($t\bar{t}$) with a generic scalar boson ($\phi$) at the LHC is proposed, using dileptonic final states of the $t\bar{t}\phi$ system with $\phi \to b\bar{b}$. The new method of mass reconstruction shows an improved resolution of at least a factor of two in the low mass region when compared to previous methods, without the loss of sensitivity of previous analyses. It turns out that it also leads to an improvement of the mass reconstruction of the 125 GeV Higgs for the same production process. We use an effective Lagrangian to describe a scalar with a generic Yukawa coupling to the top quarks. A full phenomenological analysis was performed, using Standard Model background and signal events generated with MadGraph5_aMC@NLO and reconstructed using a kinematic fit. The use of CP-sensitive variables allows then to maximize the distinction between CP-even and CP-odd components of the Yukawa couplings. Confidence Levels (CLs) for the exclusion of $\phi$ bosons with mixed CP (both CP-even and CP-odd components) were determined as a function of the top Yukawa couplings to the $\phi$ boson. The mass range analysed starts slightly above the $\Upsilon$ mass up to 40 GeV, although the analysis can be used for an arbitrary mass. If no new light scalar is found, exclusion limits at 95% CL for the absolute value of the CP-even and CP-odd Yukawa are derived. Also, we show that CP-searches are virtually impossible for $\phi$ boson masses above a few hundred GeV in the dileptonic channel, by computing CLs, as a function of luminosity, for the exclusion of different signal hypotheses with scalar and pseudoscalar bosons with masses that range from $m_{𝜙} =$ 40 GeV up to 200 GeV. Finally, we analyse how these limits constrain the parameter space of the complex two-Higgs doublet model (C2HDM).
In this report the model-independent effective field theory phenomenology is used to parameterize the anomalous couplings in the Lagrangian with higher dimensional operators. Setting limits on these operator's coefficients (EFT coupling constants) leads to new physics constraints. There are 2 terms of new physics are contained in the model: linear (interference) and quadratic. These terms were generated using decomposition method in MC event generator MG5_aMC.
In the classical version of setting these limits, all background processes are considered as non-depending on coefficients. However in general case one or several backgrounds can be affected by non-zero EFT coupling constants. This report presents the way of accounting such background processes in limits setting. As an example the electroweak $Z\gamma$ production is considered, since this process is extremely sensitive to anomalous quartic gauge couplings.
In the events of peripheral dissociation of relativistic nuclei in the nuclear track emulsion, it is possible to study the emerging ensembles of He and H nuclei, including those from decays of the unstable 8Be and 9B nuclei, as well as the Hoyle state [1-3]. These extremely short-lived states are identified by invariant masses calculated from the angles in 2α-pairs, 2αp- and 3α-triplets in the approximation of conservation of momentum per nucleon of the primary nucleus. In the same approach, it is possible to search for more complex states. This paper explores the correlation between the formation of 8Be nuclei and the multiplicity of accompanying α-particles in the dissociation of relativistic 16О, 22Ne, 28Si, and 197Au nuclei. On this basis, estimates of such a correlation are presented for the unstable 9B nucleus and the Hoyle state. An enhancement in the 8Be contribution to dissociation with the α-particle multiplicity is found. Decays of 9B nuclei and Hoyle states follow the same trend.
References
1. P.I. Zarubin, Lect. Notes in Phys., 875, Clusters in Nuclei, Volume 3. Springer Int. Publ., 51 (2013); DOI: 10.1007/978-3-319-01077-9_3; https://arxiv.org/pdf/1309.4881.
2. D.A. Artemenkov et al. Eur. Phys. J. A 56, 250 (2020); DOI: 10.1140/epja/s10050-020-00252-3.; https://arxiv.org/pdf/2102.09541.pdf
3. A.A. Zaitsev et al. https://arxiv.org/abs/2102.09541.
Here we present a solution to the long-standing problem of constructing the causal equation of state of hadron resonance gas model (HRGM) with Lorentz contracted eigenvolumes of particles with the hard-core repulsion. It is based on the concept of Induced Surface and Curvature Tension (ISCT) [1] to treat the excluded volumes of hard spheres in the high-pressure region. Its mathematically sound and extensive derivation is obtained according to principles of morphological thermodynamics [2]. Practically an exact formula for the relativistic second virial coefficient (excluded volume) is obtained and investigated for various equations of state and a wide range of temperatures $T$ and is shown that it reproduces a close packing of equal spheres limit $v_{exc}=1−\pi/(3 \sqrt{2}) \approx 0.26$ in case of high temperatures with sufficient accuracy without any prior knowledge about such system configuration. We as well propose an ansatz to take into account the effect of Lorentz contraction for higher-order virial coefficients of Boltzmann particles with hard-core repulsion. Such an ansatz allows us to obtain the expected vanishing limit for the effective relativistic excluded volume for high temperatures $T \gg m$. The proposed relativistic ISCT equation of state is applied to hadron mixtures to obtain a temperature dependence of the speed of sound $c_S$ for nucleons, pions, and light hadrons. It is shown that consideration of Lorentz contraction of only the second virial coefficient does not lead to a fully causal equation of state, since the speed of sound exceeds the speed of light by about $10\%$, but the inclusion of relativistic contraction of higher-order virial coefficients makes the ISCT equation of state causal on a wide range of temperatures even far above the temperatures of hadrons existence.
References:
[1] N. S. Yakovenko, K. A. Bugaev, L.V. Bravina and E. E. Zabrodin, Eur. Phys. J. Special Topics, 229, (2020) 3445.
[2] P.-M. König, R. Roth, and K. R. Mecke, Phys. Rev. Lett. 93, (2004) 160601.
One of the key ingredients in hadron physics based on QCD is the notion of diquark
correlations, which in turn could lead to the color superconductivity (CSC) in dense and cold quark matter with a Fermi surface to be realized in a compact star.
One of the main focuses of recent experiments using heavy-ion collision is to reveal possible rich physics in high baryon-density matter at relatively low temperature: Such experiments include the beam-energy scan program at RHIC, and HADES and NA61/SHINE collaborations as well as those to be performed in future experimental facilities such as FAIR, NICA and J-PARC-HI.
In the present report, we show that the diquark correlations or pair fluctuations of the two-flavor superconductivity (2SC) near but above the critical temperature make a well-defined collective soft modes, which may be experimentally confirmed through an anomalous enhancement of the dilepton production rate.
Indeed, on the basis of the two-flavor NJL model, we shall demonstrate that
Aslamazov-Larkin term due to the soft modes, which is known to give rise to anomalous excess of electric conductivity in metals, modify the photon self-energy so greatly that the dilepton production rates is enhanced anomalously at the low energy region.
We review recent work on Ward Identities (WI) and Effective Theories within the context of the QCD transition at finite temperature. On the one hand, WI allow to obtain generic results on the interplay between chiral and $U(1)_A$ restoration, key to understand the nature of the transition, as well as scaling laws verified by lattice screening masses. On the other hand, thermal resonances $f_0(500)$ and $K_0^*(700)$ generated within Unitarized Chiral Perturbation Theory (ChPT) scattering at finite temperature allow to describe scalar susceptibilities around chiral and $O(4)\times U(1)_A$ restoration, in good agreement with lattice results.
Four yields of strange hadrons ($\phi$ and $\bar{K}^*(892)^0$ mesons, $\Xi$ and $\Xi^-$ baryons) emitted from p+p collisions at $\sqrt{s}$ = 17.3 GeV have been recently measured by the NA61/SHINE collaboration 1. These results prompted the creation of a unified set of particle yields, combining the data from NA49 and NA61/SHINE in a consistent manner (instead of treating the measurements separately [2,3]).
We used the Thermal-FIST statistical hadronization code with the canonical ensemble required for either hadrons with open strangeness only, or all the particles [4]. With physically unjustified omission of the $\phi$ meson yield, a satisfactory fit quality is obtained. However, all the particle yields including the $\phi$ meson might be reproduced with $\chi^2$/NDF $\approx$ 1.5, if the volume of strangeness production is above that for non-strange particles. Newest NA61/SHINE results on $\Xi^0$(1530) and $\bar{\Xi}^0$(1530) baryons and $\mathrm{K}^0_S$ meson [5] are also discussed.
The larger volume of strangeness emission zone in pp interactions might be revealed via HBT investigations of production volume of strange and non-strange particles. The uncertainties of existing measurements spread over energies above SPS do not allow to verify this conjecture. A precise femtoscopic study is therefore welcome.
1 A. Aduszkiewicz et al. (NA61/SHINE Collaboration) Eur. Phys. J. C80, 199 (2020); ibid. p. 460; ibid. p. 833.
2 I. Kraus, J. Cleymans, H. Oeschler, K. Redlich, Phys. Rev. C 81, 024903 (2010).
3 V.V. Begun, V. Vovchenko, M.I. Gorenstein, H. Stoecker, Phys. Rev. C 98, 054909 (2018).
[4] T. Matulewicz, K. Piasecki, J. Phys. G: Nucl. Part. Phys. 48, 085004 (2021).
doi:10.1088/1361-6471/abfdd7
[5] NA61/SHINE Collaboration: arXiv:2105.09144, arXiv:2106.07535
We present a summary of the results obtained with the novel hadron resonance gas model based on the induced surface tension equation of state [1] with the multicomponent hard-core repulsion. This model is used to resolve the long-standing problem to describe the light nuclear cluster multiplicities including the hyper-triton nucleus measured by the STAR Collaboration, known as the hyper-triton chemical freeze-out puzzle [2]. Here we discuss an entirely new strategy to analyse the experimental data on light nuclear clusters and employing it in the analysis of hadronic and light (anti-)(hyper-)nuclei multiplicities measured by the STAR Collaboration at the center-of-mass collision energy $\sqrt{s_{NN}} = 200$ GeV and by the ALICE Collaboration at $\sqrt{s_{NN}} = 2.76$ TeV. We got rid of the existing ambiguity in the description of light (anti-)(hyper-)nuclei data and determined the chemical freeze-out parameters of nuclei with high accuracy and confidence. This success is achieved by taking into account the correct excluded volumes of light nuclei in hadronic medium and by using the small value of the hard-core radius of the $\Lambda$/$\bar{\Lambda}$ hyperons found in earlier work [1].
One of the most striking results is that for the most probable scenario of chemical freeze-out for the STAR energy the obtained parameters allow us to reproduce the multiplicities of hadrons and light (anti-)(hyper-)nuclei and, for the first time, to simultaneously describe the values of the experimental ratios $S_3$ and $\bar{S}_3$ which were not included in the fit. Our results show that the multiplicities of light nuclear clusters may be frozen prior to the hadrons at temperatures about $170-175$ MeV.
The new presented strategy allows one to determine the hard-core radii of other hyperons with high accuracy, if the yields of their hyper-nuclei are known.
References:
[1] K. A. Bugaev et al., Nucl. Phys. A 970, (2018) 133–155.
[2] O. V. Vitiuk et al., Eur. Phys. J. A 57, (2021) 74 1-12.
The quark matter created in relativistic nuclear collisions is interpreted as a nearly-perfect fluid. The recent efforts to explore its finite-density properties in the beam energy scan programs motivate one to revisit the issue of the local rest frame fixing in off-equilibrium hydrodynamics. We first investigate full second-order relativistic hydrodynamics in the Landau and Eckart frames, which are defined with energy and baryonic flows, respectively. Then we perform numerical simulations to elucidate the effect of frame choice on flow observables in nuclear collisions. The results indicate that the flow can differ in the two frames but charged particle and net baryon rapidity distributions are mostly frame independent when off-equilibrium kinetic freeze-out is considered.
Since few decades, considerable amount of research interest has been grown on the study of hot and/or dense ‘strongly’ interacting matter produced in the heavy ion collision (HIC) experiments at RHIC and LHC. On top of that, recently, another
contemporary research topic is the investigation of the effect of a strong
background magnetic field on various properties of QCD matter at extreme condition of high temperature and/or baryon density. Interestingly, a non-central or asymmetric HIC at RHIC and LHC energies has the potential to create strong magnetic field of the order of 10^18 Gauss or more. As the magnitude of the magnetic field is comparable to QCD energy scale, various novel phenomena owing to the rich vacuum structure of QCD could take place [1] such as chiral magnetic effect, magnetic catalysis, inverse magnetic catalysis etc.
Through the HIC experiments, it is possible to probe the bulk thermodynamic properties or the phase structure of QCD. The non-perturbative aspects of QCD restrict a first principle analytic calculation of the QCD thermodynamics especially in the low temperature region. The numerical lattice QCD (LQCD) based calculations [2] is one of the best alternatives to study the QCD thermodynamics, but is limited to the low baryon density region of the QCD phase diagram due to its ‘sign’ problem. On the other hand, the hadron resonance gas (HRG) model [3–5] is a statistical thermal model for studying the QCD thermodynamics at finite temperature, baryon density as well as external magnetic field [6–8]. Interestingly, at low temperature and small baryon density, the results from HRG model agrees well with the LQCD.
In the calculation of thermodynamic quantities, one generally assumes the system size to be infinite. However, in the HIC experiments, the created fireball has finite volume (few fm^3). So, it is justified to consider the boundary effects in the calculation of thermodynamical quantities pertaining to the HIC [9]. In this presentation, we will be showing the calculation of various thermodynamic quantities like energy density, longitudinal and transverse pressure and magnetization of an ideal HRG of finite size in presence of external magnetic field. The formalism of generalized Matsubara prescription [10] will be used to incorporate the finite size effect whereas the effect of external magnetic field will enter through the Landau quantization of the dispersion relations of charged hadrons.
References:
[1] D. Kharzeev, K. Landsteiner, A. Schmitt, and H.-U. Yee, eds., Strongly Interacting Matter in Magnetic Fields, Vol. 871 (2013).
[2] P. de Forcrand and O. Philipsen, JHEP 01, 077 (2007), arXiv:hep-lat/0607017.
[3] R. Hagedorn and J. Rafelski, Phys. Lett. B 97, 136 (1980).
[4] J. Cleymans and K. Redlich, Phys. Rev. C 60, 054908 (1999), arXiv:nucl-th/9903063.
[5] P. Braun-Munzinger, J. Stachel, J. P. Wessels, and N. Xu, Phys. Lett. B 344, 43 (1995), arXiv:nucl-th/9410026.
[6] G. Endrödi, JHEP 04, 023 (2013), arXiv:1301.1307 [hep-ph].
[7] A. Bhattacharyya, S. K. Ghosh, R. Ray, and S. Samanta, EPL 115, 62003 (2016), arXiv:1504.04533 [hep-ph].
[8] A. N. Tawfik, A. M. Diab, N. Ezzelarab, and A. G. Shalaby, Adv. High Energy Phys. 2016, 1381479 (2016), arXiv:1604.00043 [hep-ph].
[9] A. Bhattacharyya, R. Ray, S. Samanta, and S. Sur, Phys. Rev. C 91, 041901 (2015), arXiv:1502.00889 [hep-ph].
[10] L. M. Abreu, E. B. S. Corrêa, C. A. Linhares, and A. P. C. Malbouisson, Phys. Rev. D 99, 076001 (2019), arXiv:1903.09249 [hep-ph].
Going beyond the simplified gluonic cascades, we have introduced both gluon and quark degrees of freedom for partonic cascades inside the medium. We then solve the set of coupled evolution equations numerically with splitting kernels calculated for exponential and Bjorken expanding media to arrive at medium-modified parton spectra for quark and gluon initiated jets respectively. Firstly, we have studied the inclusive jet $R_{AA}$ by including phenomenologically driven combinations of quark and gluon fractions inside a jet. The impact of the rapidity dependence of the jet $R_{AA}$ has been studied in detail. Secondly, we have studied the path-length dependence of jet quenching for different types of expanding media by calculating the jet $v_{2}$. Additionally, we have qualitatively studied the sensitivity of the time for the onset of the quenching for the Bjorken profile on jet $v_{2}$ and comparison with data from ATLAS.
The ultra-peripheral collisions (UPCs) of relativistic heavy-ion collisions provide a unique opportunity to study the photon induced interactions
at the LHC in new kinematic regimes.
The ALICE experiment has measured the coherent photo-nuclear production of the $\rho^{0}$ and J/$\psi$ vector mesons in UPCs.
The measurement of $\rho$ vector meson is an excellent tool to study nuclear shadowing effects and the approach to the black-disc limit of QCD, while the J/$\psi$ measurement is also a good tool to study the nuclear shadowing and saturation effects at low-x.
In this contribution, recent results obtained with the data from the LHC Run2 will be presented.
The first measurement of the cross section of the $\rho^{0}$ mesons in Xe-Xe at $\sqrt{s_{NN}}$ = 5.44 TeV and Pb-Pb UPCs at $\sqrt{s_{NN}}$ = 5.02 TeV, and the cross section of the J/$\psi$ mesons and its t-dependence in Pb-Pb UPCs at $\sqrt{s_{NN}}$ = 5.02 TeV will be reported.
These results are compared with various model predictions in order to improve our phenomenological understanding of the UPCs.
In heavy ion collisions at high energies the hot and dense medium of a quark-gluon plasma (QGP) can be recreated and investigated.
We study how jets that were produced in hard binary collisions propagate and in particular how the jet-particle momentum components $k_T$ transverse to the jet-axis change.
To this end, we evolved jets within a QGP medium, in which they undergo both medium induced coherent radiation as well as scatterings that involve transverse kicks,
using the MINCAS-algorithm [1] that is based on the works of [2,3].
In this framework parton branching occurs simultaneously to scatterings within the medium, leading to the interference effects that reproduce the well known BDMPS-Z emission rates.
In the most general form the resulting parton branchings also give rise to a sizeable $k_T$ broadening.
Thus, it is interesting to compare the relative importances of $k_T$ broadening from the coherent splittings and different types of in-medium scatterings.
We find a clear hierarchy of the influences from different scattering effects and deflections during branchings [4]:
While scattering still yields the largest contributions to broadening, the branching effects are comparable in size.
However, we find that with increasing strength of jet-medium interactions $k_T$ broadening even decreases in some of the studied cases, due to
the interplay of scattering and energy loss due to branching.
References:
[1] K. Kutak, W. Płaczek, R. Straka, Eur.Phys.J. C79 (2019) no.4, 317
[2] J.-P. Blaizot, F. Dominguez, E. Iancu, Y. Mehtar-Tani, JHEP 1301 (2013) 143
[3] J.-P. Blaizot, F. Dominguez, E. Iancu, Y. Mehtar-Tani, JHEP 1406 (2014) 075
[4] E. Blanco, K. Kutak, W. Płaczek, M. Rohrmoser, R. Straka, JHEP 04 (2021) 014
With the advent of TeV-energy colliding machines, such as the Large Hadron Collider (LHC), the possibility has opened up to test predictions of Quantum Chromodynamics (QCD) and, more in general, of the Standard Model (SM), in new, and so far unexplored, kinematical regimes. Among the many reactions that can be investigated at LHC, the Higgs production is one of the most important and challenging for the entire high-energy physics Community. Beside usual studies in the Higgs sector, it has recently been highlighted how differential Higgs distributions can be effectively used as ``stabilizers" of the high-energy dynamics of QCD. The definition and the study of observables sensitive to high-energy dynamics in Higgs production has the double advantage of (i) allowing us to clearly disentangle the high-energy dynamics from the fixed-order one and (ii) providing us with an auxiliary tool to extend Higgs studies in wider kinematical regimes.
In this talk, I will show how a general hybrid collinear/high energy factorization can be built up for the inclusive production of a Higgs in association with a jet. Then, I will present some phenomenological analyses that corroborate the underlying assumption that this reaction can be used to investigate the semi-hard regime of QCD. Finally, I will focus on more formal developments, such as the inclusion of subleading corrections to previous studies, via the calculation of the forward next-to-leading order Higgs impact factor.
This note presents an analysis of the potential of future high-energy electron-positron colliders to measure the $b$-quark mass. We perform a full-simulation study of the measurement of the ratio of the three-jet rates in events with $b\bar{b}(g)$ and $q\bar{q}(g)$ production, $R_{3}^{bl}$, and assess the dominant uncertainties, including theory and experimental systematic uncertainties. We find that the ILC "Higgs factory" stage, with an integrated luminosity of 2 $ab^{-1}$ at $\sqrt{s}=$ 250 GeV can measure the $b$-quark $\overline{MS}$ mass at a scale of 250 GeV ($m_b(250~$GeV$)$ with a precision of 1 GeV. From this result we extrapolate the potential of the GigaZ run
running at $\sqrt{s}= m_Z$. We expect $m_b(m_Z)$ can be determined with an 0.12 GeV uncertainty, exceeding the precision of the LEP and SLD measurements by a factor $\sim$3.
Neutron and nuclear beta decay correlation coefficients are sensitive to the exotic scalar and tensor interactions that are beyond the Standard Model (BSM). The BRAND project aims at a test of the Lorentz structure of weak interaction in neutron decay by precision measurements of yet unexplored transverse polarization of electrons in correlation with the neutron spin and electron and recoil proton momenta. The experiment will simultaneously measure eleven neutron correlation coefficients (a, A, B, D, H, L, N, R, S , U, V), where seven of them (H, L, N, R, S, U and V) depend on the transverse electron polarization. Five of these correlations: H, L, S, U and V were never attempted experimentally before. The expected ultimate sensitivity of the proposed experiment respectively BSM couplings will be comparable to that of the ongoing and planned correlation measurements in neutron and nuclear beta decays but offers completely different systematics and additional sensitivity to imaginary parts of the scalar and tensor couplings. In the talk, an overview of the project, physical motivation and applied experimental techniques will be reported. The results of the first pilot run of the experiment performed recently using the cold neutron beam line PF1B at the Laue-Langevin Institute, Grenoble, France will be presented, with an emphasis on the challenges of the proposed proton detection technique.
BESIII has collected 448.2 M $\psi(3686)$ data set and 10 B $J/\psi$ data set. The huge clean data sample provide an excellent chance to search for new physics. We report the search for decay $J/\psi\to\gamma + invisible$, which is predicted by next-to-minimal supersymmetric model. Without significant signal found, we gave around 6.2 times better upper limits than previous CLEO-c’s results. In addition, we report the preliminary result of the first search for the invisible decay of $\Lambda$. This invisible decay is predicted by the mirror matter model which could explain the $4\sigma$ discrepancy in neutron lifetime measurement results from the beam method and bottle method.
The matter-antimatter asymmetry in the universe cannot be explained by the Standard Model of elementary particle physics. According to A. Sakharov, CP violating phenomena are needed to understand the matter-antimatter asymmetry. Permanent Electric Dipole Moments (EDMs) of subatomic elementary particles violate both time reversal and parity asymmetries and therefore also violate CP if the CPT-theorem holds.
Storage rings offer the possibility to measure EDMs of charged particles by observing the influence of the EDM on the spin motion. The Cooler Synchrotron (COSY) at Forschungszentrum Jülich provides polarized protons and deuterons up to a momentum of 3.7 GeV/c and is therefore an ideal starting point for the JEDI - Collaboration (Jülich Electric Dipole moment Investigations) to perform the first direct measurement of the deuteron EDM.
During this talk, recent results of the JEDI physics program are presented.
In this talk, the current efforts of the NOPTREX collaboration to perform TRIV studies in
different neutron - compound nucleus systems will be presented. I will describe the
experiments we are currently performing and planning for the near future to better
characterize PV asymmetries and s, p wave resonance parameters. The mixing
between these energetically close resonances is responsible for the observed
amplification in PV effects, and the same mechanism would also enhance any TRIV effect.
Beyond Standard Model (BSM) theories are typically probed in two types of experiments. In collider experiments, such as those carried out at LHC, exotic bosons are directly produced in high-energy proton - proton collisions. Another way to test BSM's, is by studying low-energy observables. This is facilitated by the small effects/currents of the same exotic bosons on these observables[1]. The shape of the beta spectrum, which is the topic of this research, is sensitive to two exotic currents, scalar and tensor, both prohibited in the SM weak interaction. For allowed transitions, these currents introduce a correction term in the spectrum, called the Fierz term bFierz , which is inversely proportional to the energy.
In addition to BSM’s, the beta spectrum shape is a useful tool to probe SM effects. One of those effects is called Weak Magnetism (WM) and is induced by QCD interactions between quarks in the nucleon. For some particular transitions, a measurement of WM can provide a good test for the Conserved Vector Current hypothesis (CVC). Furthermore, the knowledge of WM for high-mass neutron-rich nuclei is crucial in the analysis of reactor anti-neutrino experiments[2].
With this in mind, an attempt is made to measure the spectrum shape of the pure Gamow-Teller decay In114 -> Sn114, at the precision level of 10-3. To obtain a spectrum cleared from undesired systematic contributions, a plastic scintillator in combination with a multi-wire drift chamber was designed to measure the beta spectrum shape. The purpose of the drift chamber is to identify certain type of events , e.g. electrons that are backscattered from the scintillator surface, or cosmic muons. In addition to event pattern recognition, the setup allows for several filtering and calibration methods. For example, by requiring coincidence between detector and drift chamber, noise and gamma particles can be filtered. Furthermore, in order to correct for non-uniform light propagation in scintillator and light guide, tracking conversion electrons from a calibration source enables the real-time generation of a 2D-detector surface gain map.
The current results and progress with respect to detector calibration and efforts to tackle systematics in the measured 114In-spectrum will be presented. In addition, the results are compared with Monte-Carlo simulations, mainly based on Geant4 and Garfield++, as the analysis is depending on it. Finally, the preliminary results for WM extraction are shown.
[1] M. González-Alonso, O. Naviliat-Cuncic, N. Severijns. New physics searches in nuclear and neutron β decay. Progress in Particle and Nuclear Physics, 104:165-223, 2019.
[2] A. C. Hayes and P. Vogel. Reactor neutrino spectra. Annual Review of Nuclear and Particle Science, 66(1):219–244, 2016.
[3] L. De Keukeleere (2021), PhD Thesis, KU Leuven.
A search for sub-GeV dark matter (DM) will be performed by the DarkMESA experiment behind the beam dump of the MESA external electron beam in Mainz, Germany. Various dark sector models motivate the existence of sub-GeV scalar and Majorana or pseudo-Dirac DM, accessible in this type of beam-dump experiment, e.g. by coupling to a dark photon mediator $A'$. In the presence of light DM in the dark sector with masses $m_\chi < m_A'/2,$, the $A'$ would predominantly decay invisibly into those $\chi$ particles provided that the dark coupling constant $\alpha_D$ is not too small. Re-interpretations of null results in a multitude of other models are possible [1].
The experiment makes use of the high intensity electron beam available at MESA and will run parasitically to the scheduled program with the P2 apparatus. The experiment is based on a solid and reliable detection technology and will collect an unprecedented accumulated charge in a few years time, that will extend current limits on light DM [2].
[1] G. Lanfranchi et al., Feebly-Interacting Particles: FIPs 2020 Workshop Report (2020), arXiv:2102.12143.
[2] M. Christmann et al., Instrumentation and optimization studies for a beam dump experiment (BDX) at MESA $-$ DarkMESA, Nucl. Instrum. Meth. Phys. Res. A 958 (2020) 162398, DOI:10.1016/j.nima.2019.162398.
A neutron decays into a proton, an electron, and antineutrino in a lifetime of about 880 s. The neutron lifetime is one of the important parameters for particle physics and astrophysics. For instance, it dominates the uncertainty on 4He abundance in the Big Bang Nucleosynthesis and it also determines Vud term in the Cabibbo-Kobayashi-Maskawa quark mixing matrix. Although the neutron lifetime is very important in modern physics, there is a 4-sigma (8.5 s) discrepancy between the results of two typical methods: the beam method and the storage method. The beam method measures the neutron flux and decay protons by different detectors, and the storage method counts survival neutrons after some storage times. The discrepancy is called the neutron lifetime puzzle and is not yet settled. The possibility that unknown systematic errors and new physics such as dark decays are the cause has been discussed.
We have been carrying out a neutron lifetime measurement with a new method at J-PARC to solve the puzzle. In our method, we measure the neutron flux and decay electrons simultaneously by a Time Projection Chamber filled by working gas and 3He. To reduce the background event rate, the neutron beam is shaped to bunches shorter than the length of the sensitive region by the Spin Flip Chopper (SFC) and injected into the TPC. Since the neutron flux and decay rate are counted by the same detector in our method, the systematic uncertainty is different from the typical beam method. Additionally, we can measure dark decays with electrons if it exists. We are aiming for 1 s (0.1%) precision determination of the neutron lifetime to achieve a definitive result.
We have been constructed the experimental and analysis procedure to determine the neutron lifetime by our new method by the last year and the result is 898 +/- 10 (stat.) +15 -18 (sys.) s. Towards 1 s accuracy, we are now installing a new SFC of 3 times flux and it will enable us to analyze more classified events to reduce systematic uncertainties.
This presentation will report the first physics result of our experiment with acquired data during 2014 - 2016, and a detailed status and prospect of upgrades both in the apparatus and the analysis towards 1 s precision.
The goal of the TUCAN EDM experiment (TRIUMF Ultra-Cold Advanced Neutron Electric Dipole Moment experiment) is to make a new precise measurement of the neutron EDM, with uncertainty of 1x10$^{-27}$ e-cm, a one order of magnitude improvement compared to the current world's best limit. The experiment is unique in using a spallation-driven superfluid helium (He-II) source of ultracold neutrons (UCN). We have been operating a prototype UCN source at TRIUMF since 2017. We are now at the stage of upgrading this source to produce world-leading UCN densities, using a new He-II cryostat that has undergone cryogenic testing at KEK in 2020-21. We are also assembling the experimental components of the EDM experiment, including a magnetically shielded room, coils, and atomic magnetometers. This presentation will report on the data from our prototype UCN source acquired at TRIUMF, and on our recent progress upgrading the UCN source and preparing the EDM experiment.
We present novel diagrammatic methods for perturbative asymmetry calculations and the inclusion of thermal corrections. Unlike the standard approach based on Cutkosky rules, the unnatural splitting of the amplitude into couplings and imaginary parts of the loop integrals is avoided. Moreover, the presented framework allows for a unified treatment of the usual asymmetries and real-intermediate-state-subtracted reaction rates (traditionally introduced to avoid double-counting in the Boltzmann equation). The $S$-matrix unitarity and $CPT$ symmetry constraints between the asymmetries of different reactions are derived systematically at any order in coupling constants. They remain valid even when thermal corrections are taken into account via winding the propagators in Feynman diagrams on a cylindrical surface before the cutting is performed. The resulting thermally corrected source-term for the lepton number asymmetry is equivalent to the outcome of the closed-time-path formalism of non-equilibrium quantum theory. As an example, we use the asymmetric reaction rates in the seesaw type-I leptogenesis to demonstrate how the method works. The talk is primarily based on arXiv:2104.06395, arXiv:2102.05914.
The astrophysical r-process of nucleosynthesis is widely considered to explain the production of stable and neutron-rich isotopes beyond the iron peak. Taking place at temperatures above 1 GK and very high densities, it is believed to occur in extreme astrophysical scenarios (e.g., [1, 2]), such as supernova explosions or neutron star and black hole collisions. In order to study stellar nuclear
reactions computer simulations are commonly used. Simulation models of the r-process depend on a very large number of nuclear parameters. Thus, this nucleosynthesis mechanism poses great interest to both astrophysics and nuclear physics.
One of the most important parameters that impacts calculation of the neutron capture rates is the masses of participating nuclei, especially in the little-studied exotic isotope regions of the nuclide chart. Most of such masses were obtained not experimentally, but from theoretical models. For some isotopes different models predict significantly different values, which brings uncertainties to r-process calculations.
It was found in the first part of our research [3], that theoretical r-process yeilds of some isotopes are strongly dependent on the choice of the nuclear mass model. In this study different nuclear mass models were used to create a number of reaction rate libraries, analogous to the REACLIB [4]. Reaction rates and their cross sections calculation was performed using the TALYS package [5].
Following nuclear mass models were considered by us in this scope: the macro-microscopic models FRDM [6] and WS4 [8], the Skyrme interaction-based HFB mass model [7], and our mass evaluation based on local mass relations [9]. The latter is based on a phenomenological approach, assuming that the residual neutron-proton interaction energy behaves smoothly as a function of the mass number.
These reaction rates libraries were subsequently used to carry out simulations of the r-process. For this purpose we have used a nuclear reaction network of about 7000 isotopes and corresponding reactions with macroscopic conditions. Our implementation is based on the SkyNet modular nuclear reaction network library [10].
Final mass distributions of the nucleosynthesis products were obtained in an r-process scenario at 1.2 GK and the sensitivity of the calculation to the choice of the nuclear mass model was estimated. Comparison of the results of different models in the interval A = 60 ÷ 220 was performed. Obtained r-process isotopes yields show the differences of the considered mass models.
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\author{Venkataramana Shastri\thanks{venkataramana.shastri@gmail.com}, Aswathi V and S P Shilpashree}
\title{Theoretical Studies on Pion Photoproduction on Deuterons}
\affil{School of Engineering and Technology, CHRIST (Deemed to be University), Bangalore, India}
\date{18/06/2021}
\maketitle
\section{Abstract}
The study of nuclear reactions between elementary particles and atomic nuclei plays an important role in understanding the interdisciplinary area
of Nuclear Physics and Particle Physics.
The study of photoproduction of mesons has a long history going back to $1950’s.$
It was in the next decade studies on photoproduction of $\pi$ meson on deuteron started.
Since then coherent and incoherent photoproduction of $\pi$ meson on deuteron have been studied theoretically and experimentally.
The study of photoproduction of pions describe the coupling among photon, meson and nucleon fields and also gives information about strong interactions
that indirectly hold the nucleus together.
A thorough investigation of the photoproduction process is firmly believed to give first hand information on two important aspects, one being the threshold of
$\pi$ photoproduction amplitude and the other being propagation of low-energy pions in nuclear medium.
The purpose of the present contribution is to theoretically study pion photoproduction on deuterons using model independent
irreducible tensor formalism developed earlier to study the photodisintegration of deuterons.\cite{gr2006-1}
\begin{thebibliography}{}
\bibitem{gr2006-1}G Ramachandran, S P Shilpashree Phys. Rev. C {\bf 74}, 052801(R) (2006)
\end{thebibliography}
\end{document}
Di-neutron correlations are extensively explored in recent experiments, and the enhancement of the spatial localization of the pair of the neutrons (n) has been confirmed at the nuclear surface in the light neutron-excess systems, such as $^{11}$Li and $^{19}$B. The spatial localization of two neutrons, which is called “the di-neutron correlations”, are also investigated theoretically by employing the three-body model with core + n + n. The analysis of the di-neutron correlation gives an important key to elucidate the surface structure of neutron stars. If the di-neutron configuration is stabilized in the nuclear medium, there is a possibility of the formation of new phase with the di-neutron condensation at the surface of the neutron star.
If we consider the three-body system of core plus two neutrons, the spatial localization of two neutrons corresponds to the formation of “di-neutron cluster” around the core nucleus. On the other hand, the valence neutrons usually perform the independent particle motion around the core nucleus, and the ground state of the normal nucleus is explained by the so-called the nuclear shell model. The shell model configuration and the di-neutron one seem to be very different structure intuitively but these two configurations are non-orthogonal, and there is a finite amplitude of the di-neutron cluster component even if the pure shell model state is realized. Thus, in order to understand the feature of the di-neutron cluster more deeply, it is important to evaluate the overlap integral of the di-neutron cluster state and the shell model state, which is a measure of the non-orthogonal amplitude of these two different states.
We have developed a new formula to evaluate the overlap integral of the cluster and shell-model configurations, and the formula is applied to the core + n + n systems. In this report, we will report the systematic feature of the overlap integrals of the di-neutron cluster state (core + 2n) and the shell model state (core + n + n) with a variation of the core mass number. In particular, we will discuss the enhancements of the overlap integral in connection to the single particle orbits of the valence two neutrons in the shell model states.
The outcome of any possible nucleosynthesis scenario is strongly affected by the photodisintegration of nuclei through (γ, N) and (γ, np) channels for Eγ > 10MeV to a few hundred MeV. Though there is a wide range of phenomenological models for the estimation of excitation functions in this energy region, the exact photodisintegration mechanism is not well understood. The shell-model based approaches have not been successful even for the light nuclei of astrophysical importance like 6Li [1]. By extending the Independent PAir Model [2] (IPAM), a SRC-based approach is employed to calculate the photo-disintegration of light nuclei in quasideuteron region. Combining the Gunn-Irving photo-disintegration for α-cluster [3], the proposed approach is used to calculate the total photo-disintegration cross-sections for Eγ between 10 to 140 MeV for many of the N=Z light nuclei from 4He to 40Ca. Contrary to general perception, the quasideuteron photo-disintegration contribution starts in the GDR region itself [4] and dominates at Eγ > 50 MeV. Along with many interesting new insights, the derivation of the Levinger [5] formula is obtained without any additional assumption. A significant fraction of the photo-disintegration cross-section in GDR region may be accounted by contribution of quasi-α degree of freedom which decreases for higher Eγ. The present work suggests an alternative and viable description of photodisintegration for N=Z nuclei in terms of np-SRCs/quasideuteron structures and their paired counterparts.
References
[1] S. Bacca, and S. Pastore, Electromagnetic reactions on light nuclei, J. Phys. G: Nuc. Part. Phys. 41, 123002 (2014).
[2] L. C. Gomes, J. D. Walecka, and V. F. Weisskopf, Properties of nuclear matter, Ann. Phys. 3, 241 (1958).
[3] J. C. Gunn, and J. Irving, The photo-electric disintegration of three- and four-particle nuclei, Phil. Mag. 42 1353 (1951).
[4] A.Veyssière, H. Beil, R. Bergère, P. Carlos, A. Leprêtre, A. De Miniac, A study of the photoneutron contribution to the giant dipole resonance of s-d shell nuclei, Nuc. Phys. A 227, 513 (1974).
[5] J. S. Levinger, The high energy nuclear photoeffect, Phys. Rev. 84, 43 (1951).
The Majorana Demonstrator is an experiment searching for neutrinoless double beta decay in $^{76}$Ge. The Demonstrator consists of 44 kg (30 kg enriched in $^{76}$Ge) germanium detectors in two modules operating at the 4850' level of the Sanford Underground Research Facility in Lead, South Dakota. The experiment has recently concluded its primary physics data taking campaign in March 2021, having operated since 2015. Published results with a 26 kg-yr exposure achieved a world-leading energy resolution of 2.5 keV FWHM at the double beta decay Q-value, one of the lowest background indices at the double beta decay Q-value, and a half-life lower limit of $2.7 \times 10^{25}$ yr (90% C.L.). The low backgrounds, low-energy thresholds, and excellent energy resolution also enable competitive searches for double-beta decay to excited states and beyond the Standard Model physics. In 2020, one module underwent significant hardware upgrades, which involved replacing several p-type point contact (PPC) detectors with four larger, novel geometry inverted coaxial point contact (ICPC) detectors. In this talk, we present the latest results of the Majorana Demonstrator including, the increased available exposure, improved analysis, and performance since the upgrade.
In this talk I will study the case where dark matter emerges from a complex scalar field charged under a U(1) global symmetry, which is spontaneously broken. Our analysis considers different explicit symmetry breaking terms motivated by discrete symmetries. I will show results which demonstrate that in some regions of the parameter space these scenarios may be distinguished by combining different observables, such as direct detection and collider signatures. Finally we discuss the case where the stabilising symmetry may be broken, as well as an effective operator approach valid in the pseudo-Nambu-Goldstone limit.
The current best estimate for the universe’s matter content consists of 84% dark matter, and the search for its composition remains of great interest. One possible candidate is a so-far undetected ultra-low-mass axion. Various astronomical observations and laboratory experiments constrain the axion mass and its interaction strength in the allowed phase space. In this talk, we present the idea of a complementary laboratory search for an axion-induced oscillating neutron electric dipole moment using a cold neutron beam Ramsey setup. We show results from recent measurements with the Beam EDM setup at the Institut Laue-Langevin that resulted in further constraints of the axion-gluon coupling.
Liquid argon (LAr) is one of the most promising targets for the search of WIMP-like dark matter. LAr dual-phase time projection chamber (LAr TPC) is a leading technology, able to detect both the scintillation and ionization signal. The correlation in the two signal channels provides a possible handle to measure the recoil direction of the nuclei: if confirmed, this would allow inferring the incident direction of potential dark matter candidates.
Previous work from SCENE resulted in a hint of the existence of a directional effect, which can potentially pave the way for a tonne scale directional WIMP search with LAr TPC. To validate this hypothesis, we conducted the Recoil Directionality (ReD) experiment to measure this correlation in 70 keV nuclear recoils to the highest precision.
The ReD TPC was carefully calibrated and then irradiated with a neutron beam at the INFN Laboratori Nazionali del Sud, Catania, Italy. A model based on directional modulation in charge recombination was developed to explain the correlation. In this contribution, we describe the experimental setup, the theoretical model, and the preliminary results from data analysis.
COSINUS (Cryogenic Observatory for the search of SIgnatures seen in Underground Sites) is a new experiment aiming at the detection of galactic dark matter particles scattering off atomic nuclei. It is based on the employment of cryogenic scintillating calorimeters made up of sodium iodide crystals operated at millikelvin temperature. The construction of the impressive COSINUS infrastructure, whose installation will start soon in the National Laboratory of Gran Sasso, has been strongly motivated by a first specific goal: providing a conclusive statement on the nature of the annually modulated signal detected by the DAMA/LIBRA experiment. Such signal, measured using room temperature scintillators, is compatible with the expectations for the detection of galactic dark matter particles, but it has not been confirmed by any other experiments so far. For this reason, COSINUS is cross-checking the results of the DAMA/LIBRA experiment by using the same target material (sodium iodide) but applying a different technology. Indeed, COSINUS reconstructs the energy released in the target material by measuring both the energy converted into lattice vibrations and into scintillation light. Relying on the particle-dependent light yield, an efficient background rejection can be achieved on an event-by-event basis. In this talk, we will provide an update on the status of the COSINUS experiment and on the last results of our detector design optimisation studies, with a particular focus on the COSINUS phenomenology of detection and on the description of the relevant parameters which enter in the comparison among the several NaI-based experimental results.
Heavy leptons with masses ranging from the GeV to the TeV appear in several Beyond the Standard Model (BSM) mechanisms, aimed to explain the neutrino mass generation. The seesaw mechanism provides an elegant extension of the Standard Model (SM) explaining the smallness of the neutrino masses. In particular, it introduces at least one extra fermionic triplet field with zero hypercharge in the adjoint representation of SU(2)_L which couples to electroweak gauge bosons. These new charged and neutral heavy leptons could be produced via EW processes at the Large Hadron Collider (LHC).This search is performed using data collected by the ATLAS detector at sqrt(s)=13 TeV with an integrated luminosity of 139^-1 corresponding to the full Run-2 dataset recorded in LHC Run 2 (2015-2018). The analysis is focused on final states with large lepton multiplicity, which allows to reject a significant part of background providing an higher signal significance. For the first time, a result considering a combination of the most important type-III seesaw heavy leptons decay modes is presented.
The data on tau neutrino is very scarce, only a few experiments have detected its interactions. At FNAL beam dump experiment DONUT, tau neutrino interaction cross-section was directly measured with a large systematical (~50%) and statistical (~30%) errors. The main source of systematical error is due to a poor knowledge of the tau neutrino flux. The effective way for tau neutrino production is the decay of Ds mesons, produced in proton-nucleus interactions. The DsTau experiment at CERN-SPS has been proposed to measure an inclusive differential cross-section of a Ds production with a consecutive decay to tau lepton in p-A interactions. The goal of experiment is to reduce the systematic uncertainty to 10% level. A precise measurement of the tau neutrino cross section would enable a search for new physics effects such as testing the Lepton Universality (LU) of Standard Model in neutrino interactions. The detector is based on nuclear emulsion providing a sub-micron spatial resolution for the detection of short length and small “kink” decays. Therefore, it is very suitable to search for peculiar decay topologies (“double kink”) of Ds→τ →X. After successful pilot runs and data analysis, CERN had approved the DsTau project as a new experiment NA65 in 2019. During the physics runs, 2.3×10^8 proton interactions will be collected in the tungsten target, and about 1000 Ds→τ decays will be detected. In this talk, the results from the pilot run will be presented and the prospect for physics runs in 2021-2022 will be given.
Neutrinos are probably the most mysterious particles of the Standard Model. The mass hierarchy and oscillations, as well as the nature of their antiparticles, are currently being studied in experiments around the world. Moreover, in many models of the New Physics, baryon asymmetry or dark matter density in the universe are explained by introducing new species of neutrinos. Among others, heavy neutrinos of the Dirac or Majorana nature were proposed to solve problems persistent in the Standard Model. Such neutrinos with masses above the EW scale could be produced at future linear e+e- colliders, like the Compact LInear Collider (CLIC) or the International Linear Collider (ILC).
We studied the possibility of observing production and decays of heavy neutrinos in qql final state at the ILC running at 500 GeV and 1 TeV and the CLIC running at 3 TeV. The analysis is based on the WHIZARD event generation and fast simulation of the detector response with DELPHES. Dirac and Majorana neutrinos with masses from 200 GeV to 3.2 TeV are considered. Estimated limits on the production cross sections and on the neutrino-lepton coupling are compared with the current limits coming from the LHC running at 13 TeV, as well as the expected future limits from hadron colliders. Impact of the gamma-induced backgrounds on the experimental sensitivity is also discussed. Obtained results are stricter than other limit estimates published so far.
The Short-Baseline Near Detector (SBND) will be one of three liquid Argon Time Projection Chamber (LArTPC) neutrino detectors positioned along the axis of the Booster Neutrino Beam (BNB) at Fermilab, as part of the Short-Baseline Neutrino (SBN) Program. The detector is currently in the construction phase and is anticipated to begin operation in the second half of 2022. SBND is characterised by superb imaging capabilities and will record over a million neutrino interactions per year. Thanks to its unique combination of measurement resolution and statistics, SBND will carry out a rich program of neutrino interaction measurements and novel searches for physics beyond the Standard Model (BSM). It will enable the potential of the overall SBN sterile neutrino program by performing a precise characterisation of the unoscillated event rate, and by constraining BNB flux and neutrino-Argon cross-section systematic uncertainties. In this talk, the physics reach, current status, and future prospects of SBND are discussed.
We study the future sensitivities to a non-unitarity neutrino mixing matrix for different short-baseline coherent elastic neutrino-nucleus scattering (CEvNS) proposed experiments. We also identify the best configuration for measuring the oscillation parameters on the (3+1) scheme for light sterile neutrinos and find the estimated sensitivity for their parameters. Finally, we study the conversion to massive sterile neutrinos (in the keV-MeV energy mass) through transition magnetic moments and find the sensitivites for actual COHERENT results as well as future experiments of CEvNS and electron neutrino scattering with a proposed Cr-51 neutrino source experimental setup.
The super-weak force is a minimal, anomaly-free U(1) extension of the standard model (SM), designed to explain the origin of (i) neutrino masses and mixing matrix elements, (ii) dark matter, (iii) cosmic inflation, (iv) stabilization of the electroweak vacuum and (v) leptogenesis. We discuss the neutrino sector of this model in detail and study the allowed parameter space of the neutrino Yukawa matrices and mixing matrix elements. The model generates nonstandard neutrino interactions, whose allowed experimental limits are used to constrain the parameter space of the model. We provide benchmark points in the relevant parameter space that fall within the sensitivity region of the SHiP and MATHUSLA experiments.
In the search for the CP-violation in the leptonic sector, crucial information has been obtained from neutrino experiments. The measurement of the third neutrino mixing angle, θ13, opened the possibility of discovering the Dirac leptonic CP violating angle, 𝛿CP with intense “super” neutrino beam experiments. In the light of these new findings, an urgent need has arisen to improve the detection sensitivity of the current long-baseline detectors, considering proton driver at MW scale with a MegaTon scale detector, with a key modification to place the far detectors at the second, rather than the first, oscillation maximum.
The European Spallation Source neutrino Super Beam (ESS𝜈𝜈SB) aims to benefit from the high power of the European Spallation Source (ESS) LINAC in Lund-Sweden, to produce the world’s most intense second-generation neutrino beam in order to search and measure, with precision, the CP-violation in the leptonic sector, at 5𝜎 significance level in more than 60% of the 𝛿CP range.
Here I will shed light on the current design study programs running within the collaboration and the physics potential of the experiment.
We implement a minimal linear seesaw model (LSM) for addressing the Quasi-Dirac (QD) behaviour of heavy neutrinos, focusing on the mass regime of $M_{N} < M_{W}$.
Here we show that for relatively low neutrino masses, covering the few GeV range, the same-sign to opposite-sign dilepton ratio, $R_{\ell \ell}$, can be anywhere between 0 and 1, thus signaling a Quasi-Dirac regime. Particular values of $R_{\ell \ell}$ are controlled by the width of the QD neutrino and its mass splitting, the latter being equal to the light-neutrino mass $m_{\nu}$ in the LSM scenario. The current upper bound on $m_{\nu_{1}}$ together with the projected sensitivities of current and future $|U_{N \ell}|^{2}$ experimental measurements, set stringent constraints on our low-scale QD mass regime. Some experimental prospects of testing the model by LHC displaced vertex searches are also discussed.
This talk presents a model of the electron-like excess observed by the MiniBooNE experiment comprising of oscillations involving two new mass states: $\nu_4$, at $\mathcal{O}(1)$ eV, that participates in oscillations, and $\mathcal{N}$, at $\mathcal{O}(100)$ MeV, that decays to $\nu+\gamma$ via a dipole interaction.
Short-baseline oscillation data sets, omitting MiniBooNE appearance data, are used to predict the oscillation parameters. We simulate the production of $\mathcal{N}$ along the Booster Neutrino Beamline via both Primakoff upscattering ($\nu A \to \mathcal{N} A$) and Dalitz-like neutral pion decays ($\pi^0 \to \mathcal{N} \nu \gamma$).
The simulated events are fit to the MiniBooNE neutrino energy and visible scattering angle data separately to find a joint allowed region at 95\% CL.
A point in this region with a coupling of $3.6 \times 10^{-7}$ GeV$^{-1}$, $\mathcal{N}$ mass of 394 MeV, oscillation mixing angle of $6\times 10^{-4}$ and mass splitting of $1.3$ eV$^2$ has $\Delta \chi^2/dof$ for the energy fit of 15.23/2 and 37.80/2. This model represents a significant improvement over the traditional single neutrino oscillation model.
Neutrino-less double beta decay(0$\nu\beta\beta$) is acquiring great interest after the confirmation of neutrino oscillation which demonstrated nonzero neutrino mass. Measurement of 0$\nu\beta\beta$ can provide a test for the Majorana nature of neutrinos and gives an absolute scale of the effective neutrino mass.
The CANDLE project is the challenge to discovery of $^{48}$Ca 0$\nu\beta\beta$. Among double beta decay nuclei, $^{48}$Ca has an advantage of the highest Q$_{\beta\beta}$-value (4.27 MeV). This large Q$_{\beta\beta}$-value gives a large phase-space factor to enhance the 0$\nu\beta\beta$ rate and the least contribution from natural background radiations in the energy region of the Q$_{\beta\beta}$-value. Therefore, good signal to background ratio is expected in a 0$\nu\beta\beta$ measurement.
In order to search for 0$\nu\beta\beta$ of $^{48}$Ca, we have constructed the CANDLES-III system by using CaF$_{2}$ scintillators at the Kamioka underground laboratory, ICRR, the University of Tokyo. The CANDLES-III system aims at a high sensitive measurement by a characteristic detector system. The system realizes a complete 4$\pi$ active shield by immersion of the CaF$_{2}$ scintillators in liquid scintillator. The active shield leads to a low background condition for the measurement. And we have also installed a shielding system in the CANDLES-III system to reduce background events by the high energy $\gamma$-rays, which were emitted from neutron capture reaction on surround materials. By the system, we reduced the background events from neutron capture by two orders of magnitude. After this upgrade, the system has achieved low background measurement with background level of 10$^{-3}$ events/keV/yr/(kg of $^{nat.}$Ca) at the Q$_{\beta\beta}$-value. This is comparable or less than those of other sensitive experiments for double beta decay. Based on the result, we also started development for a next generation detector system for $^{48}$Ca double beta decay measurement. In this system, we will use a CaF$_{2}$ scintillating bolometer and enriched $^{48}$Ca.
In this paper, we will report result of $^{48}$Ca double beta decay measurement by the CANDLES-III system and current status of the CaF$_{2}$ scintillating bolometer and enrichment of $^{48}$Ca.
Coherent elastic neutrino-nucleus scattering (CEνNS) offers a unique way to study neutrino properties and to search for new physics beyond the Standard Model.
The NUCLEUS experiment aims at measuring the CEνNS signal from reactor antineutrinos. The detector will consist of a newly developed 10 g target array of CaWO4 and Al2O3 cryogenic calorimeters with demonstrated ultra-low threshold of ~20 eV, an energy region never explored so far. The experiment will be installed between the two pressurized water reactors of the Chooz B power plant in the French Ardennes. Currently, the experiment is under construction and the commissioning of the full apparatus is expected to start in 2022.
This talk will present the expected sensitivity of the NUCLEUS experiment to the CEνNS signal as well as its physics potential. The current status and the next steps of the experiment will be reported.
Over the last decades, Inverse Beta Decay (IBD) antineutrino experiments conducted at short and long baselines from nuclear reactors have revealed significant discrepancies on both the rate and shape of the measured spectra compared to state-of-the-art predictions. No evidence for an experimental bias has been detected, and the sterile neutrino interpretation of the reactor antineutrino anomaly has been mostly excluded by recent very short baseline reactor experiments. The validity of the predictions is then questioned as the source of the observed discrepancies. This last lead has motivated a revision of reactor antineutrino spectrum modeling as a new generation of reactor experiments investigating Coherent Elastic Neutrino-Nucleus Scattering (CEνNS) will continue to rely on predictions.
In this context, a revisited prediction of reactor antineutrino spectra using the summation method has been developed, including a thorough propagation of the uncertainties associated to both the modeling and the nuclear data. In this talk, I will detail the many improvements this new prediction brings over the previous modelings. I will show a comparison of this new modeling to other state-of-the-art predictions as well as some IBD datasets collected by recent short and long baseline reactor experiments. Finally, the low energy portion of the reactor antineutrino spectrum will be discussed in regards to the current experimental effort aiming at observing CEνNS at reactors.
The Scintillating Bubble Chamber (SBC) Collaboration is constructing a 10-kg liquid argon bubble chamber with scintillation readout. The goal for this new technology is to achieve a nuclear recoil detection threshold as low as 100 eV with near complete discrimination against electron recoil events. In additional to a dark matter search, SBC is targeting a CEvNS measurement of MeV-scale neutrinos from nuclear reactors. A high-statistics, high signal-to-background detection would enable precision searches for beyond-standard-model physics. I will discuss the status of SBC, the CEvNS physics reach, calibration and background challenges, and new techniques being considered by SBC to realize a precision sub-keV nuclear recoil calibration, such as nuclear Thomson scattering and Ar-40 neutron capture calibrations.
Radiotherapy, one of the techniques used to treat cancer, can be divided into conventional (gamma and electrons) and heavy charged particles radiotherapy. The latter, realized mainly with proton or carbon nuclei, has been highly anticipated due to its dose deposition profile, which presents a high deposition region at its end - the Bragg Peak. Dose deposition profile affects the risk to the surrounding healthy tissues and the existence of a Bragg Peak allows to increase the dose in the target region, whilst minimizing the dose to surrounding healthy tissues, reducing the risk of the technique. The control and monitoring of the Bragg Peak location can further increase the precision of the treatment. One way to perform this monitoring is to measure the prompt-gamma detected perpendicular to the incident proton beam. For that purpose a detector with a GSO scintillator crystal, connected to a SiPM is being studied. A set of blades in front of the sensor will act as a collimator to ensure that only perpendicular photons are detected. Currently SiPM coupled to GSO crystals time and amplitude structure is being studied to design a DAQ for the full prototype with O(100) sensors. This poster will focus on the prototype system and its concept.
With the growing demand for better and improved technics in treating cancer in Portugal, there is an ongoing discussion of the need to build a proton therapy centre as well as train skilled labour in this field. In result, there is a need for high precision measuring instruments that supply real-time measures of dose (J/kg) at a tissue or DNA level, where the variance values are large enough to create undesirable errors.
The goal of this work is to develop a new detector capable of measuring real-time doses with sub-millimeter resolution, constructed using juxtaposed thin plastic scintillating fibers (PSF, 0.25, 0.5 and 1 mm) coupled with a readout by a multi-anode photomultiplier (MAPMT, 64 channels) and a suitable data acquisition (DAQ) system. In this poster it is discussed the characterization of the full detection chain (optical fibers, MAPMT and DAQ), measuring quantities such as optical and electrical crosstalk, noise, linearity, and stabilization using UV LEDs. To conclude the characterization, several radioactive sources (Cs-137, Co-60, Tl-204 and Am-241) were used.
Several studies show that the combination of high-Z nanoparticles and external radiotherapy leads to an increased radiation effect in tumoral cells without an increase of the patient dose. However, it is not yet clear how the sequence of physical, chemical, and biological mechanisms contributes to the observed synergic effect.
The objective of this work is to develop simulation tools that allow the analysis and interpretation of radiobiology studies with multifunctional nanoparticles (NPs). To do that, we will develop realistic simulations of the irradiation of monolayer (2D) and spheroid (3D) human glioblastomas multiforme (GBM) cell cultures, taking into consideration different concentrations and cellular and subcellular distributions of the gold nanoparticles (AuNPs).
The simulations will be implemented based on TOPAS [1] software more specifically the extension TOPASn-Bio [2] that includes models of the physical and chemical processes induced by radiation at the DNA scale. These must describe the laboratory experimental conditions of irradiation with X-rays, Co-60 sources and with proton beams considering the cell lines morphology and 2D and 3D cell culture scenarios. The construction of the computational cell models will be developed based on confocal microscopy images of the biological samples.
Based on the simulations, the dose distributions at the subcellular scale will be obtained, as well as the temporal distribution of the reactive oxygen species (ROS) induced by the different irradiation conditions, AuNPs distribution, and concentrations. The microdosimetric distributions in cells will be used to predict cell survival fractions, using standard mathematical models of the biological effects of radiation as Local Effect Model (LEM) [3], Nanodosimetric Oxidative Stress (NanOx) [4] and Microdosimetric Kinetic Model (MKM) [4].
The results obtained in the simulations will be compared with the biological in vitro and in vivo experimental results, which will include evaluation of cell viability and survival. Moreover, the simulated ROS yields will be also compared with the experimentally determined values.
[1] J. Perl, et al., “Topas: an innovative proton Monte Carlo platform for research and clinical applications”, Med Phys, 39:6818-37, 2012.
[2] J. Schuemann, et al., “Topas-nbio: An extension to the topas simulation toolkit for celular and sub-cellular radiobiology," Radiat Res, 191:125-138, 2019
[3] T. Elsasser, et al., “Quantification of the relative biological effectiveness for ion Beam radiotherapy: direct experimental comparison of proton and Carbon ion beams and a novel approach for treatment planning”, Int. J. Radiation Oncology Biol. Phys., Vol. 78, No. 4, pp. 1177–1183, 2010
[4] M. Cunha, et al., “NanOx, a new model to predict cell survival in the context of particle therapy”, Phys. Med. Biol. 62 1248, 2017
[5] Christian P Karger and Peter Peschke, “RBE and related modeling in carbon-ion therapy”, Phys. Med. Biol. 63 01TR02, 2018
The quark-gluon plasma (QGP) which emerges in collisions of ultra-relativistic heavy-ions can be probed with jets, collimated showers of hadrons resulting from fragmentation of highly-virtual partons after a hard scattering. The jet shower interacts with the QGP via collisional and radiative processes that lead to a phenomenon known as jet quenching which manifests itself by suppression of high-pT jet yields and jet shape modifications. The observed modifications carry information about the transport properties of the QGP.
In this presentation, we report the nuclear modification factor measurements of full jets in Pb-Pb collisions at √sNN = 5.02 TeV taken with the ALICE experiment at the LHC. The jet energy scale is corrected for the large, fluctuating underlying event with the area based method, where the underlying event density is obtained either with the traditional or machine learning based estimators. The machine learning estimator enables to access lower transverse momenta and larger jet radii than previously possible in ALICE. The potential bias introduced by the machine learning method is investigated and its impact is quantified.
In the wake of the recent measurements of the decays B → J/ψ π(K) and B → J/ψ lν reported by the LHCb Collaboration we calculate c c l
the form factors for the B → J/ψ and B → η transitions in full kinematical region within covariant confined quark model. Then we use the c c c
calculated form factors to evaluate the partial decay widths of the above-mentioned semileptonic and nonleptonic decays of the B meson. c
We find that the theoretical predictions on the ratios of R and R are in good agreement with the last LHCb-data. However, the prediction K+/π+ π+/μ+ν
for the R is found to be underestimated.
Videos available till December 31, 2021
Standard Model at the TeV Scale: https://youtu.be/B1I5Hr1HGm8
DM and Cosmology: https://youtu.be/5qRh-Q61VZo
Neutrino Physics: https://youtu.be/m5GiFfZvRu8
Flavour physics: https://youtu.be/dQzSUsajA9Q
Tests of symmetries: https://youtu.be/I1eU25BlW-8
Hadron spectroscopy: https://youtu.be/r91FSKpvuSA
QCD, spin, chiral dynamics: https://youtu.be/Q4azmww01QQ
Nuclear and Particle Astrophysics: https://youtu.be/WJfThcZf-Xg
EIC & Hot and dense matter: https://youtu.be/JhPZWd5caOc
Hadrons in medium: https://youtu.be/OkNv_ls-aw0
Accelerators&Detectors, Data Science, Gravitational Waves, Best Posters: https://youtu.be/chr0o472KkA
Videos available till December 31, 2021
Standard Model at the TeV Scale: https://youtu.be/B1I5Hr1HGm8
DM and Cosmology: https://youtu.be/5qRh-Q61VZo
Neutrino Physics: https://youtu.be/m5GiFfZvRu8
Flavour physics: https://youtu.be/dQzSUsajA9Q
Tests of symmetries: https://youtu.be/I1eU25BlW-8
Hadron spectroscopy: https://youtu.be/r91FSKpvuSA
QCD, spin, chiral dynamics: https://youtu.be/Q4azmww01QQ
Nuclear and Particle Astrophysics: https://youtu.be/WJfThcZf-Xg
EIC & Hot and dense matter: https://youtu.be/JhPZWd5caOc
Hadrons in medium: https://youtu.be/OkNv_ls-aw0
Accelerators&Detectors, Data Science, Gravitational Waves, Best Posters: https://youtu.be/chr0o472KkA
The E989 collaboration has recently published the most precise measurement of the muon anomalous magnetic moment 𝑎𝜇 with an uncertainty of 460 ppb. The new experimental world average of 𝑎𝜇 deviates by 4.2 standard deviations from the Standard Model prediction provided by the Muon g-2 Theory Initiative. The emerging results from ab-initio lattice QCD calculations allow to scrutinize this tantalizing hint for physics beyond the Standard Model for the first time in a three way comparison. To extract the value of 𝑎𝜇 a clock comparison experiment is performed with spin-polarized muons confined in a superbly controlled electric and magnetic field environment. The deviation of the Larmor from the cyclotron frequency, the anomalous spin precession frequency, is determined while a high-precision measurement of the magnetic field environment is performed using nuclear magnetic resonance techniques. I will discuss the most recent result from the first science data run in 2018 and will report on the experimental improvements implemented to achieve the ultimate goal of 140 ppb uncertainty on 𝑎𝜇.
Videos available till December 31, 2021
Standard Model at the TeV Scale: https://youtu.be/B1I5Hr1HGm8
DM and Cosmology: https://youtu.be/5qRh-Q61VZo
Neutrino Physics: https://youtu.be/m5GiFfZvRu8
Flavour physics: https://youtu.be/dQzSUsajA9Q
Tests of symmetries: https://youtu.be/I1eU25BlW-8
Hadron spectroscopy: https://youtu.be/r91FSKpvuSA
QCD, spin, chiral dynamics: https://youtu.be/Q4azmww01QQ
Nuclear and Particle Astrophysics: https://youtu.be/WJfThcZf-Xg
EIC & Hot and dense matter: https://youtu.be/JhPZWd5caOc
Hadrons in medium: https://youtu.be/OkNv_ls-aw0
Accelerators&Detectors, Data Science, Gravitational Waves, Best Posters: https://youtu.be/chr0o472KkA
We introduce here a new method to measure the Higgs decay branching ratios at future $e^+e^-$ Higgs factories, by directly exploiting class numeration. Given the clean environment at a lepton collider, we build an event sample highly enriched in Higgs bosons and essentially unbiased for any decay mode. The sample can be partitioned into categories using event properties linked to the expected Higgs decay modes. The counts per category are used to fit the Higgs branching ratios in a model independent way. The result of the fit is directly the set of branching ratios, independent from any measurement of a Higgs production mode. Special care is given to an appropriate treatment of the statistical uncertainties. In this contribution, the current status of our implementation of this analysis within the ILD concept detector is presented.
Many physics analyses in Higgs, top and electroweak physics improve the kinematic reconstruction of the final state by constrained fits. This is a particularly powerful tool at $e^+e^-$ colliders, where the initial state four-momentum is known and can be employed to constrain the final state. A crucial ingredient to kinematic fitting is an accurate estimate of the measurement uncertainties, in particular for composing objects like jets. This contribution will show how the particle flow concept, which is a design-driver for most detectors proposed for future Higgs factories, can -- in addition to an excellent jet energy measurement -- provide detailed estimates of the covariance matrices for each individual particle-flow object and each individual jet. Combined with information about leptons and secondary vertices in the jets, the kinematic fit enables to correct $b$- and $c$-jets for missing momentum from neutrinos from semi-leptonic heavy quark decays. The impact on the reconstruction of invariant di-jet masses and the resulting improvement in $ZH$ vs $ZZ$ separation will be presented, using as an example the full simulation of the ILD detector concept. As an outlook, the expected benefit for the Higgs self-coupling measurement from double Higgs production will be discussed.
Among the high-energy physics community, there is a growing interest in replacing cut-based selections using different types of multivariate analysis. This transformation made it possible to use high-level variables produced by complex reconstruction algorithms.
Within this context, Deep Learning approaches are rapidly spreading to improve the selection performances by combining all the available information. The development of these algorithms often relies on a brute force approach where all available event features are tested for multiple combinations of the algorithm hyperparameters. Nonetheless, the significance of the prediction does not necessarily increase with the amount of information given as input to the algorithm. The opposite is often true.
Herein, we propose an effective method to choose the most valuable variables to give as input to a Deep Neural Network using a CancelOut layer. Indeed, given a fixed number of variables, the CancelOut layer selects during training only the most relevant features to achieve the best performances. We use as a study case the selection of events where a boosted large and massive jet contains both of the $b$~quarks originated from $H$ boson decays. We show how the Deep Neural Network classifier performance can be affected by keeping irrelevant variables in input and how our method can naturally get rid of them. The proposed method can be easily implemented in already developed Deep Neural Network classifiers through a retraining campaign.
The Yukawa coupling of the Higgs boson to the top quark is a key parameter of the Standard Model. This coupling can be directly measured from the process of gg/qq -> ttH. And the multilepton channel is the most sensitive channel in this process. A search for ttH production in multilepton final states has been performed with an integrated luminosity of 80 fb-1 at a centre-of-mass energy of 13 TeV. Results will be presented.
We evaluated CLAS Collaboration measurements for the 90-deg meson photoproduction off the nucleon using a tagged photon beam spanning the energy interval s = 3 – 11 GeV2. The results are compared with the “quark counting rules” predictions. The role of the Sudakov form-factor and Vector-Meson Dominance model is considered.
We analize the most general low-energy effective lagrangian including local parity violating terms parametrized by an axial chemical potential $\mu_5$. This result is obtained following the external source method, up to $\mathcal{O}(p^4)$ order in the chiral expansion for two light flavours. We show that the $\mathcal{O}(p^4)$ lagrangian includes new terms proportional to $\mu_5^2$ and new low-energy constants. Finally, the $\mu_5$ and temperature dependences of several observables related to the vacuum energy density are studied. The same procedure can be followed to incorporate isospin chemical potential.
In this talk we show how to apply the SCET formalism to factorize Double Drell-Yan process involving a pion and a proton, with four leptons and the proton in the final state. We will show how the factorization of the cross-section leads to the appearance of a Double TMD and two GTMDs. Additionally, we will show how the subsequent zero-bin subtraction leads to the appearance of a new Soft Factor and how the rapidity divergences work out at one-loop level.
LHCb is a spectrometer that covers the forward region of proton-proton collisions, corresponding to the pseudo-rapidity range 2<eta<5. In this unique phase space, LHCb can perform tests of perturbative and non-perturbative QCD models, by studying the production of heavy flavor quarks, like charm and top quarks. In this context the production of a Z boson in association with a c-jet can be studied to measure the intrinsic charm content of the proton. Moreover LHCb can test phenomenological models of soft QCD processes, by measuring the production of forward hadrons in pp collisions.
Jets, clusters of collimated particles produced in high energy proton-proton ($pp$) collisions, are an excellent tool to study the internal structure of the proton. According to perturbative QCD calculations, for center of mass energies of $\sqrt{s} = $ 200 and 510 GeV at RHIC, jet production in the mid pseudo-rapidity, $|\eta| <$ 1, is dominated by quark-gluon and gluon-gluon scattering processes. These jets are sensitive to gluons in the proton with momentum fraction 0.01 $