2012/12/05 by A. Dainese, Dainese, Andrea
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1212.0995
The ALICE experiment studies nucleus-nucleus collisions at the LHC in order\nto investigate the properties of QCD matter at extreme energy densities. The\nmeasurement of open charm and open beauty production allows one to probe the\nmechanisms of heavy-quark propagation, energy loss and hadronization in the hot\nand dense medium formed in high-energy nucleus-nucleus collisions. In\nparticular, in-medium energy loss is predicted to be different for massless\npartons (light quarks and gluons) and heavy quarks at moderate momentum. The\nALICE apparatus allows us to measure open heavy-flavour particles in several\ndecay channels and with a wide phase-space coverage.\n We present the results on the nuclear modification factors for heavy-flavour\nparticle production in Pb-Pb collisions at sqrtsNN=2.76 TeV. Using\nproton-proton and lead-lead collision samples at sqrts=2.76 and 7 TeV and at\nsqrtsNN=2.76 TeV, respectively, nuclear modification factors RAA(pT) were\nmeasured for D mesons at central rapidity (via displaced decay vertex\nreconstruction), and for electrons and muons from heavy-flavour decays, at\ncentral and forward rapidity, respectively. A large suppression is observed, by\na factor 2.5-4 in central Pb--Pb collisions with respect to the pp reference,\nin the high-pT region, indicating a strong in-medium energy loss of heavy\nquarks.\n