Quarkonium measurements in nucleus–nucleus collisions with ALICE

Abstract

Quarkonia, i.e. bound states of bb¯ and cc¯ quarks, are powerful observables to study the properties of nuclear matter under extreme conditions. The formation of a Quark-Gluon Plasma (QGP), which is predicted by lattice QCD calculations at high temperatures as reached at the LHC energies, has a strong influence on the production and behavior of quarkonia. The latest ALICE results on bottomonium and charmonium production in nucleus−nucleus collisions are presented. This includes measurements of the Υ(1S) and Υ(2S) nuclear modification factor (RAA) at forward rapidity and the J/ψ RAA and v2 as a function of centrality, pT and rapidity in Pb−Pb collisions at √sNN = 5.02 TeV. Also, first results from J/ψ measurements in Xe−Xe collisions at √sNN = 5.44 TeV are presented. Further on, the experimental results are compared to various calculations from theoretical models.