UC Berkeley

The inclusive J / ψ meson production in Pb–Pb collisions at a center-of-mass energy per nucleon–nucleon collision of s NN = 5.02 TeV at midrapidity ( | y | < 0.9 ) is reported by the ALICE Collaboration. The measurements are performed in the dielectron decay channel, as a function of event centrality and J / ψ transverse momentum p T , down to p T = 0 . The J / ψ mean transverse momentum 〈 p T 〉 and r AA ratio, defined as 〈 p T 2 〉 PbPb / 〈 p T 2 〉 pp , are evaluated. Both observables show a centrality dependence decreasing towards central (head-on) collisions. The J / ψ nuclear modification factor R AA exhibits a strong p T dependence with a large suppression at high p T and an increase to unity for decreasing p T . When integrating over the measured momentum range p T < 10 GeV / c , the J / ψ R AA shows a weak centrality dependence. Each measurement is compared with results at lower center-of-mass energies and with ALICE measurements at forward rapidity, as well as to theory calculations. All reported features of the J / ψ production at low p T are consistent with a dominant contribution to the J / ψ yield originating from charm quark (re)combination.