"AMBER is a newly proposed fixed-target experiment at CERN devoted to
various fundamental QCD measurements, with a Letter of Intent recently
The elastic muon-proton scattering process is proposed as a novel approach to the
long-standing puzzle of the proton charge radius. This quantity was recently measured
using two different but very accurate techniques, with results that differ by 5 sigma.
The high energy muon scattering experiment now proposed may clarify the situation,
thanks to the lower systematics involved.
The origin of hadron masses is deeply connected to the issue of gluon
dynamics, and how it differs in protons or mesons. While the nucleon
parton distributions are known with good precision already, the pion ones
are very poorly known, the last measurements being more than 30 years
old and suffering from very large uncertainties. The kaon parton dynamics, on
the other hand, was never measured. A new high intensity beam line with
hadron species separation using radio-frequency techniques offers a unique
opportunity to study mesonic parton distributions, by exploring both Drell-Yan
and direct photon production.
The antiproton production cross-section is a necessary input in the
indirect searches of dark matter from the antiproton flux in galactic cosmic
rays as measured by the AMS experiment. The proposed AMBER measurements in p+p
and p+$^4$He collisions cover a range from tens to few hundred GeV,
complementary to those from LHCb which are in the TeV range.
These and many more measurements planned at the AMBER experiment will be
presented. Feasibility, world competition and possible timelines will be
discussed. AMBER is the challenging but natural extension of the COMPASS
searches in QCD."