Inclusive J/ψ production in Pb–Pb collisions at √s_NN = 5.02 TeV with ALICE

The J/ψ mesons is a bound state of a charm quark and its anti-quark. The production of J/ψ mesons serves as an important probe of the quark-gluon plasma (QGP) formed in heavy-ion collisions. The presence of the deconfined strongly interacting medium results in the color screening of the potential between charm quarks and anti-quarks created during hard scattering processes. At sufficiently high collision energies such as the LHC energy, the large abundance of produced charm quarks leads to the (re)generation of J/ψ mesons during the QGP evolution and/or at the phase boundary. In this work, the J/ψ production yield in Pb–Pb collisions at √s_NN = 5.02 TeV recorded by ALICE is measured at midrapidity via the dielectron decay channel J/ψ → e+e− as a function of centrality and as a function of transverse momentum down to p_T = 0.15 GeV/c in the most central and semi-central collisions. The J/ψ nuclear modification factor R_AA increases slightly from semi-central to the most central collisions. The p_T -differential J/ψ R_AA shows a large suppression of the J/ψ yield at high p_T and the J/ψ R_AA increases with decreasing p_T. The measurement is compared to other experimental results and to model calculations. The presented results strongly support picture of (re)generation as an important J/ψ production mechanism at the LHC especially significant at low p T and at midrapidity