Heavy ion physics at LHC with CMS detector

The CMS ( Compact Muon Solenoid) is a general purpose detector, optimised for p-p collisions at LHC. However, a very good muon system, fine granularity and excellent energy resolution of electromagnetic and hadron calorimeters and high quality central tracker gives the possibility of using the detector for specific heavy ion studies. Various ways of searching for the phase transition from hadronic matter to the plasma of deconfined quarks and gluons ( QGP) in heavy ion collisions with CMS detector have been investigated: Production of ( bb) and ( cc) resonant states through their muon decay channel to study the colour-screening effect. The dimuon mass spectra and rates of heavy quark bound state production for two weeks of running time are presented. Expected statistics will be sufficient to perfom the Upsilon family suppression study. Detection of J/Psi is mostly concentrated in the forwa rd region. Z production and its subsequent mu+mu- decay can be detected with high statistics and very low background ( 4%). To study energy losses of a hard parton in QGP ( ''jet quenching'') three different processes have been considered: QCD jet pair, Z+jet and gamma+jet production. The possibility of jet recognition in central Pb-Pb collisions has been investigated. For transverse energy jets ET > 50 GeV the recognition efficiency is close to 100%.