Speaker
Christophe Suire
(CNRS-IN2p3)
Description
Heavy quarkonium states are expected to provide essential information on the properties of the high-density strongly-interacting system formed in the early stages of heavy-ion collisions. In particular the J/psi suppression, in heavy-ion collisions, via color screening mechanism, can be seen as a direct effect of deconfinement.
During 25 years, the J/psi suppression has been extensively studied at the SPS and at RHIC. It was indeed clearly observed but to a level surprisingly
similar despite the large difference in the center of mass energy at the two accelerators.
At the same time, new mechanisms of J/psi regeneration via recombination of charm and anti-charm quarks were also proposed. The measurement of J/psi suppression is especially promising at the Large Hadron Collider where the high energy density of the medium and the large number of charm quarks pairs produced in central Pb-Pb collisions should help to disentangle between the different suppression and recombination scenarios.
ALICE is the LHC experiment mainly dedicated to the study of nucleus-nucleus collisions. At forward rapidity (2.5 < y < 4), the J/psi production is measured in the Muon Spectrometer, via the mu+ mu- decay channel, down to zero transverse momentum.
After a brief description of the apparatus, the analysis of the inclusive J/psi production in Pb-Pb collisions at a center of mass energy of sqrt(Snn)= 2.76 TeV will be discussed. Results on the nuclear modification factor (Raa) dependence on the collision centrality will be shown.
Thanks to the large statistics collected in 2011, preliminary results on Raa as a function of transverse momentum and rapidity will also be presented.
Primary author
Christophe Suire
(CNRS-IN2p3)
