Inclusive, prompt and non-prompt J/ ψ production at mid-rapidity in Pb-Pb collisions at s N N = 2.76 TeV

The transverse momentum ( p T ) dependence of the nuclear modification factor R AA and the centrality dependence of the average transverse momentum 〈 p T 〉 for inclusive J /ψ have been measured with ALICE for Pb-Pb collisions at s N N = 2.76 TeV in the e+e − decay channel at mid-rapidity (| y | < 0 . 8). The 〈 p T 〉 is significantly smaller than the one observed for pp collisions at the same centre-of-mass energy. Consistently, an increase of R AA is observed towards low p T . These observations might be indicative of a sizable contribution of charm quark coalescence to the J /ψ production. Additionally, the fraction of non-prompt J /ψ from beauty hadron decays, f B , has been determined in the region 1 . 5 < p T < 10 GeV /c in three centrality intervals. No significant centrality dependence of f B is observed. Finally, the R AA of non-prompt J /ψ is discussed and compared with model predictions. The nuclear modification in the region 4 . 5 < p T < 10 GeV /c is found to be stronger than predicted by most models.