Heavy Ion Physics with CMS at LHC

par Prof. Bolek Wyslouch (MIT and CERN)

vendredi 13 juin 2008, 14:00 → 15:00 Europe/Paris

Auditorium (LAPP-Annecy)

"Heavy Ion Physics with CMS at LHC" The Large Hadron Collider at CERN will collide protons at sqrt{S}=14 TeV and lead ions at sqrt{S_{NN}}=5.5 TeV. The physics program of the Compact Muon Solenoid (CMS) includes the study of heavy ion collisions. The high energies available at the LHC will allow high statistics studies of the dense partonic system with hard probes: heavy quarks and quarkonia with an emphasis on the b and Upsilon, high p_T jets, photons, as well as Z0 bosons. The CMS detector consists of a 13~m long, 6~m wide superconducting solenoid providing a uniform 4~T magnetic field. Charged particles will be measured with a large acceptance, high resolution silicon tracker consisting of pixel and strip detector layers. The tracker is surrounded by electromagnetic and hadronic calorimeters located inside the magnet while the muon detector is outside. The central detector will be complemented by CASTOR, a proposed forward calorimeter, and a ZDC. The tracking system and the muon detector provide hermetic coverage for particles with |eta|>=2.4. The high granularity, high resolution calorimeters will provide hermetic coverage for |eta|>=7. The CMS data acquisition system, with its reliance on a multipurpose, high-level trigger system, is uniquely qualified for efficient triggering in high-multiplicity heavy ion events. The CMS detectors will allow a wide range of unique measurements in nuclear collisions. The excellent calorimeters combined with tracking will allow detailed studies of jets, particularly medium effects on the jet fragmentation function and the energy and p_T redistribution of particles within the jet. The large CMS acceptance will allow detailed studies of jet structure in rare jet-gamma and jet-Z0 events. The high resolution tracker will tag b quark jets. The muon chambers combined with tracking will study production of the Z0, J\psi and the Upsilon family in the central rapidity region of the collision. In addition to the detailed studies of hard probes, CMS will measure charged multiplicity, energy flow and azimuthal asymmetry event-by-event. The forward detector suite, including hadron calorimeter, CASTOR, the ZDC and TOTEM will study forward energy flow and charged multiplicity in the fragmentation region as well as the relative charged and neutral energy fluctuations. The combination of the forward hadron calorimeter and the ZDC will determine the collision centrality. Detailed studies of the CMS capabilities using the full detector simulation and reconstruction will be presented.

BWyslouch_HeavyIons_CMS wyslouch_annecy_june_2008_v1.ppt