(2S) production in Pb-Pb collisions measured by ALICE at the LHC

Charmonium production is a probe sensitive to deconfinement in nucleus-nucleus collisions. The production of J/ via regeneration within the QGP or at the phase boundary has been identified as an important ingredient for the description of the observed J/ nuclear modification factor at the LHC. The (2S) production relative to J/ is a possible discriminator between the two regeneration scenarios. Studies of (2S) production in central nucleus-nucleus collisions at low transverse momentum (p ₓ) are crucial, particularly at the LHC, where regeneration appears to be dominant. A significant (2S) signal is extracted at low p ₓ and forward rapidity in the dimuon decay channel for the first time. This measurement relies on the (2S) cross section measured recently in pp collisions at s =5. 02 TeV with an unprecedented precision compared to previous ALICE results. In this contribution, we present newly published results on the (2S) -to-J/ ratio and the (2S) nuclear modification factor in Pb--Pb collisions at s ₍₍=5. 02 TeV. Results are reported as a function of centrality and p ₓ for p ₓ<12 GeV/c and are compared to available NA50 and CMS measurements. Comparisons to transport and statistical hadronization model predictions are also provided to shed light on the charmonium states recombination mechanism.