Overview of results on heavy flavour and quarkonia from the CMS collaboration

摘要

The non-prompt J/ψ from B-meson decays, the prompt J/ψ, the inclusive ψ' and the three γ states were measured separately using the Compact Muon Solenoid (CMS) experimental apparatus in both pp and heavy-ion collisions at √s_(NN) = 2.76 TeV. The results are based on data collected in 2011 which correspond to an integrated luminosity of 150 μb~(?1) of PbPb and 231 nb~(-1) of pp collisions. The yields measured in heavy-collisions are compared to those in pp scaled by the number of binary collisions via the nuclear modification factor, R_(AA). The high-pT prompt J/ψ show a suppression that does not vary with rapidity or p_T. The R_(AA) versus centrality calculated separately for Υ(1S) and Υ(2S), shows less suppression for the ground state. An upper limit for Υ(3S) was also calculated. Combining all the quarkonia states R_(AA) measured by CMS, and considering the binding energy of each state, an ordering of the suppression is observed, which establishes, experimentally, the validity of the sequential melting scenario in heavy-ion collisions. The non-prompt J/ψ R_(AA) dependence with p_T and rapidity was measured in fine bins of centrality. These represent the first detailed measurements, in heavy-ion collision, of the b-quark energy loss kinematic dependence.