ALICE is the only LHC experiment fully dedicated to study the Quark Gluon Plasma in heavy ion collisions. The Irfu is involved in the study of the muon pairs coming from the decay of heavy resonances (ϒ and J/ψ), one of the most striking probes of the quark gluon plasma.
According to the Quantum Chromodynamics (QCD), the fundamental theory of the strong interaction, a phase transition between the ordinary nuclear matter and a Quark Gluon Plasma (QGP) should occur for a high energy density (ε ~ 1 GeV/fm3) or temperature (T ~ 200 MeV). In the QGP, the elementary components of matter, the quarks and gluons, are no more confi ned inside the hadrons and are moving freely. The conditions of energy density and temperature needed are reached in the most central Pb-Pb collisions at the LHC, where the energy available in the nucleon-nucleon center of mass is √ sNN = 5.5 TeV. This energy is ~25 times larger than in previous experiments at the RHIC collider. The SPhN group is focused in the study of heavy resonances (ϒ and J/ψ) screening as a signature of the QGP. The resonances are detected through the dimuon decay channel, where the muons are reconstructed in the forward Muon arm.
The detector is installed in the point 2 of the LHC at CERN near Geneva.
The IRFU is mainly interested in the study of the production of quarkonia reonances as probes of the quark-gluon plasma.
The IRFU is thus involved in the realization of the ALICE muon spectrometer. The IRFU contributed to the design and the realization of the 5 tracking stations.
The IRFU was in charge of:
The make the most of the luminosity upgrade of the LHC foreseen for 2018 the lectronics and read-out system of the muon spectrometer must be upgraded.
To extend the physics program of the ALICE muon spectrometer a silicon pixel tracker will be placed between the crossing point of the LHC beams and the muon spectrometer.
Alberto BALDISSERI: Coordinator of the ALICE muon spectrometer
Hervé BOREL: Coordinator of the muon spectrometer upgrade
Fabienne ORSINI: Technical coordinator of the MFT
last update : 12-06 17:54:00-2013 (2239)