The Muon Spectrometer of the ALICE experiment

Heavy ion collisions at relativistic energies are a unique tool for creating very hot and dense matter in a laboratory. In particular, lattice chromodynamics (lQCD) predicts a cross-over toward a new state of matter called Quark Gluon Plasma (QGP) at T∼ 170 MeV for μB ∼ 0. (where T is the temperature and μB the baryonic chemical potential) [ 1]. Heavy ion collisions allow us to experimentally study the properties of this new state of matter. This experimental program started in the mid 80s with fixed target heavy ion experiments at AGS and SPS [ 2] and has continued with the physics program developed at the RHIC collider (BNL) [ 3]. Heavy ion collisions in the future Large Hadron Collider (LHC) at CERN will open new experimental insights in the study of hadronic matter at high temperature. The ALICE experiment will be the only experiment at LHC devoted to the heavy ion physics [ 4], whereas the ATLAS and CMS experiments plan to develop a heavy-ion program [ 5, 6] in parallel with their main physics program. The LHC collider will provide proton and lead high luminosity beams at 7.0 TeV and 2.75A TeV momentum, respectively. At such ultra-relativistic energies new phenomena emerge, improving the experimental scenario for studying the hadronic matter in nucleus-nucleus central collisions: