Recent detections of gravitational waves provide a new, exciting tool to observe the Universe. I will introduce this new method of directly studying the spacetime distortions produced by massive objects, and focus on recent findings of the LIGO-Virgo detector network, reporting on the binary systems of black holes and neutron stars, the latter also observed in electromagnetic waves.
Dark Matter (DM) particles from the galactic halo can get gravitationally trapped inside stars. Once these particles settle in the interior of the star, DM-DM and DM-nucleon interactions can have an impact on the standard stellar evolution and the observations associated with it. These effects can in turn be used to probe the nature of galactic DM.
In this work I will discuss the underlying...
The nature and properties of dark matter are arguably among the most important open issues in science. Interesting candidates for dark matter include light bosonic fields. Such scalar fields can give rise to confined structures, as boson stars or Q-balls. Boson stars are interesting hypothetical new "dark matter stars", but also good descriptions of dark matter haloes when the fields are...
Little Higgs Models are a compelling solution to the hierarchy problem, avoiding quadratically divergent contributions to the Higgs mass through collective symmetry breaking. A signature of this model (and other composite Higgs models) would be the existence of heavy vector like fermions. In this talk we will explore the phenomelogical signatures of a heavy vector like lepton with exotic decays.
In this talk, I will discuss non-minimal predictions from the composite Higgs framework and the corresponding phenomenology. I will focus on collider signals of heavy leptons and novel top decays via a FCNC interaction.
The measurements of the Higgs signal strengths are turning out to be very SM-like at LHC experiments. As the precision increases, the parameter space of several BSM models is starting to shrink considerably. This is puzzling, as there is evidence that the SM cannot be the whole story: the massiveness of neutrinos, the strong hypothesis of Dark Matter, the small amount of CP-violation for...
The study of the top quark properties provides not only an important test of the Standard Model (SM) of particle physics but also an excellent way of probing physics beyond it. In the SM the top quark decays via Flavour Changing Neutral Currents (FCNC) have extremely small branching ratios but some extensions predict a significant enhancement of the probability for such decays. The PhD thesis...
Why should PhD students in particle physics, astrophysics and cosmology worry about the current and future challenges of distributed computing? Should not we all focus on core scientific problems, and then let others deal with how to find, provision and exploit the technologies that are required? This talk will show how that was not the case in the past and will likely not be the case also for...
Dust grains are key ingredients in understanding the interstellar medium (ISM) and the largests effect of dust on astronomical observations: the extinction of light in the line of sight and the wavelength dependent reddening it causes, both affecting distance measurements for cosmology when using extragalactic sources such as supernovae. Size, shape and distribution of the dust grains may also...
As machine-learning and deep-learning techniques become more and more ingrained in academic research tasks, two problems that researchers invariably face are:
1) How to train and apply models in a timely manner without sacrificing performance;
2) And how to do so with only a limited hardware-budget.
In my recent [paper][1] [1], I explore how recent techniques for neural network training...
In the High-Luminosity phase of the LHC physics program, the accelerator will provide an additional integrated luminosity of 3000 fb-1. One of the main challenges that must be overcome is the very high pileup (PU) originated by the high luminosity.
Each of the colliding beams at the LHC consists of many intense bunches of protons. At the HL-LHC, the average number of interactions in a...
Significant progress has been made in the study of the Higgs boson in the last few years, and in the search of additional scalars. The large datasets already collected by the Large Hadron Collider experiments allow for ever more precise measurements, while the development of innovative tools and novel theoretical ideas open new windows in the exploration of the Higgs sector. Highlights of the...
Following the observation of associated production of a Higgs boson with a pair of top-anti-top quarks (ttH), it is now essential to explore the detailed properties of the Higgs-Top coupling to test the predictions of the Standard Model of Particle Physics and search for clues of new physics that can modify this interaction. This talk describes the search to constrain odd charge-parity (CP)...
The observation of the Higgs boson production in association with a top quark pair (ttH) by ATLAS and CMS in 2018 directly confirmed the existence of the top quark Yukawa coupling. The Standard Model (SM) predicts a CP-even structure to this coupling, but a CP-odd component can arise in models beyond the SM (BSM). Recently, ATLAS and CMS searched for such a component in analyses targetting ttH...
In my presentation, I will motivate the use of angular observables as a probe of anomalous Spin/CP components in the HWW interaction vertex. I will present the results of the first ATLAS search of associated WH production in the boosted regime, where the sensitivity to these components is higher. I will also motivate and present some of my work as part of the ATLAS jet trigger group.
In a quantum filed theory, the determination of the analytic structure of the propagators, i.e., the position of poles and branch cuts for complex momenta, can be obtained within the perturbative solution of the theory. The analytic structure has information on the properties of the associated quanta and, particularly, if they are or not confined particles. In Quantum Chromodynamics the...
This project makes part of the planned upgrade work for the years 2025-26 of the ATLAS experiment, one of the four experiments located at the Large Hadron Collider (LHC), at CERN, the biggest proton - proton collider ever built. Due to the expected increasing levels of luminosity, leading to a higher amount of data generated per bunch crossing, an improvement in the trigger system, which is...
Observables extracted from lattice computations are usually described using continuum tensors. However, continuum symmetries only partially survive the discretization of spacetime. This leads to the need to consider appropriate tensor bases to characterize lattice correlation functions. We investigate the gluon propagator for pure Yang-Mills formulation using lattice tensors..
The analysis...
The Standard Model of Particle Physics (SM) is one of the most successful theories in Physics. However, it has failed to explain some observed phenomena as is the case for dark matter. To address this issue, particle physicists turn to models Beyond the Standard Model (BSM). The Next-to-minimal 2-Higgs Doublet Model (N2HDM) is a Standard Model extension that provides phenomenology compatible...
The TileCal is an hadronic calorimeter and an essential part of the ATLAS experiment at the LHC. The active material is made of plastic scintillating tiles. The light is produced in the scintillators and transmitted to the photomultiplier tubes by optical fibres.
The current plans foresee a second high luminosity LHC phase where the luminosity can reach a value seven times higher than the...
In the Standard Model (SM), the Higgs boson is predicted to be a scalar with no CP-violating interactions. After the observation of the Higgs boson production in association with a top quark pair (ttH), the measurement of an odd charge-parity (CP) component in one of the Higgs boson couplings would constitute an important discovery of physics beyond the SM. This poster describes the search for...
The Standard Model can be considered an approximation at a lower energy of a more fundamental theory which encourages the search for new physics. One evidence supporting that new particles beyond the SM might exist comes from astrophysical measurements that point to the existence of a kind of matter that does not interact with the electromagnetic force, usually referred to as Dark Matter (DM)....
In this talk I will present some generalities on the paradigm of flavour symmetries, and the benefits that it encompasses. Given the large multiplicity of scenarios in which this paradigm is included, I will focus on two specific works (in progress): approximate Yukawa symmetries in the context of 2HDMs; and subgroup-preserving points (stabilizers) in the context of discrete modular symmetries...
Hadron formation is a rather complex problem in the realm of non-perturbative QCD and remains an open question in HEP, despite the significant progress recently made through detailed phenomenological studies of several quarkonium production measurements made at the LHC. A new piece in the global panorama of quarkonium production data has recently been added by CMS: the first measurement of the...
The critical region of the two flavour quark-meson model with vector interactions is explored using the Functional Renormalization Group, a non-perturbative method that takes into account quantum and thermal fluctuations. Special attention is given to the low temperature and high density region of the phase diagram, which is very important to construct the equation of state of compact stars....
Searching for the neutrinoless double beta decay (0νββ) is of major interest to understand the fundamental characteristics of neutrinos. If observed, it would prove the Majorana nature of neutrinos, i.e. they are their own anti-particles, and allow the measurement of their effective mass.
SNO+ is a large volume liquid scintillator neutrino experiment that will search for this decay using...
SNO+ is a liquid scintillator-based experiment located 2km underground at SNOLAB in Canada. The primary motivation of the experiment is the observation of neutrinoless double beta decay; with other aims of detecting: geo and reactor antineutrinos, invisible nucleon decays and low energy solar neutrinos. The detector will operate in 3 main phases, using: ultra pure water, pure scinitllator and...
In this work, we study cosmological and astrophysical applications of the recently proposed generalized hybrid metric-Palatini gravity theory, which combines features of both the metric and the Palatini approaches to the variational method in f(R) gravity. This theory arises as a natural generalization of the hybrid metric-Palatini gravity which has been proven to be the first theory to unify...
I will review the main theoretical aspects of the standard cosmological model, commonly known as the "Big Bang theory”, its observational achievements and finally its main open problems, describing some of the leading solutions that have been proposed in the literature.
Bondi-like (single-null) characteristic formulations of general relativity are used for numerical work in both asymptotically flat and anti-de Sitter spacetimes. Well-posedness of the resulting systems of partial differential equations, however, remains an open question. The answer to this question affects the accuracy and reliability of conclusions drawn from numerical studies based on such...
In spherical symmetry compelling numerical evidence suggests that in general relativity solutions
near the threshold of black hole formation exhibit critical behavior. One aspect of this is that
threshold solutions themselves are self-similar and are, in a certain sense, unique. To an extent
yet to be fully understood, the same phenomena persist beyond spherical symmetry. It is...
A search for vector-like quarks is presented, which targets their decay into a Z boson and a third-generation Standard Model quark. In the case of a vector-like quark T (B) with charge +2/3e (−1/3e), the decay targeted is T → Zt (B → Zb). A dataset corresponding to 139/fb of pp collisions at √s = 13 TeV, collected between 2015 and 2018 with the ATLAS detector during Run 2 with the Large Hadron...
The idea of this talk is making the audience aware and reflect on skills that are important for a career in science and elsewhere. They are proposed from the perspective of someone more experienced, without any claim of specific expertise. We will start by presenting the Vitae Researcher Development Framework. This framework classifies several useful transversal skills both in scope and in...
The LUX-ZEPLIN (LZ) detector, currently in the final stage of development, is being assembled in the Davis Laboratory at SURF (Sanford Underground Research Facility, South Dakota, USA), at a depth of 1500m.
This presentation will focus on the key aspects of the Control group whose mission is to ensure the detector safety, monitorization and control during operations.
Muon Tomography is an imaging technique that uses muons as a means of observing the earth’s subsurface and with it obtain muographs that display the column density distribution of the surveyed region. The University of Évora and the LIP intend to develop muon telescopes and apply the muon tomography in the geophysics field.
The detection will take place inside the Lousal Mine, about 18 m...
A measurement of the production cross section of the top quark pair decay with a tau lepton in the final state that is carried out in the 13TeV proton-proton collisions data collected with the Compact Muon Solenoid detector at Large Hadron Collider. The ratio to the cross section in the light dilepton final states and the partial width of the top quark decay to tau lepton are also estimated....
Future cosmological data from the Euclid space mission will allow us to test many hypotheses of the nature of Dark Energy. In this talk I present an alternative approach to ΛCDM, a class of models where dark matter and dark energy exist as a single fluid, usually called Unified Dark Matter-Energy models (UDM). I will present the results of testing an UDM model implemented in the Boltzmann...
