2023/09/15 by Feuillard, Victor
#FOS: Physical sciences #Nuclear Experiment (nucl-ex)
paper · doi:10.48550/arxiv.2309.08356
Charmonium production is a probe sensitive to deconfinement in nucleus-nucleus collisions. The production of J/ψ via regeneration within the QGP or at the phase boundary has been identified as an important ingredient for the description of the observed J/ψ nuclear modification factor at the LHC. The ψ(2S) production relative to J/ψ is a possible discriminator between the two regeneration scenarios. Studies of ψ(2S) production in central nucleus-nucleus collisions at low transverse momentum (p\rm T) are crucial, particularly at the LHC, where regeneration appears to be dominant. A significant ψ(2S) signal is extracted at low p\rm T and forward rapidity in the dimuon decay channel for the first time. This measurement relies on the ψ(2S) cross section measured recently in pp collisions at √s\rm =5.02 TeV with an unprecedented precision compared to previous ALICE results. In this contribution, we present newly published results on the ψ(2S)-to-J/ψ ratio and the ψ(2S) nuclear modification factor in Pb-Pb collisions at √s\rm NN=5.02 TeV. Results are reported as a function of centrality and p\rm T for p\rm T<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