Charmonium production in Pb-Pb collisions at forward rapidity in ALICE

¹ IJCLab
² Université Paris-Saclay, France

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Published online: 17 April 2026

Abstract

Quarkonium production in high-energy collisions is a valuable tool to study both perturbative and non-perturbative aspects of QCD. Charmonia, such as the J/ψ and ψ(2S), are bound states of charm and anti-charm quarks. The ψ(2S), being less bound than the J/ψ, is more sensitive to the quark-gluon plasma (QGP) formed in heavy-ion collisions. its suppression relative to the J/ψ can reveal how different states are modified in the QGP. The ψ(2S) to J/ψ yield ratio in Pb-Pb, compared to pp collisions, helps isolate medium effects. In this article, the current status of the analysis of inclusive J/ψ and ψ(2S) production at forward rapidity (2.5 <y < 4) in Pb-Pb collisions at a center-of-mass energy per nucleon pair of √sNN = 5.36 TeV is presented. The study is based on 2023 data obtained with the upgraded ALICE apparatus during LHC Run 3, using a larger data sample with respect to the results from Run 2. The ψ(2S)- to-J/ψ ratio is presented as a function of the charmonium transverse momentum (p_T) and event centrality and is compared to the extrapolated ratio from pp collisions, and to existing theoretical models.