$J/\psi$ suppression and QCD phase diagram

TL;DR

This paper investigates the QCD phase diagram by analyzing how $J/\psi$ suppression varies with collision centrality in heavy-ion collisions, linking suppression patterns to the phase transition parameters.

Contribution

It introduces a method to extract the QCD critical line and its curvature from $J/\psi$ suppression data, highlighting discrepancies with lattice QCD predictions.

Findings

QCD critical line curvature parameter $\kappa$ is estimated to be between 0.018 and 0.23.

The extracted $\kappa$ is about three times larger than lattice QCD results.

$J/\psi$ suppression patterns are consistent with a phase transition in the QCD phase diagram.

Abstract

QCD phase diagram is obtained by analysing centrality dependence of $J/\psi$ suppression in $\snn$=17.3 Pb+Pb and $\snn$=200 GeV Au+Au collisions. $J/\psi$'s produced in initial interactions are assumed to dissolve if local temperature exceeds a threshold temperature. The threshold temperature depends on the (local) fluid temperature and baryonic chemical potential, which are obtained, under certain assumptions, from experimentally determined quantities e.g. rapidity density, net baryon density. QCD critical line with curvature parameter $\kappa\approx 0.018-0.23$ is consistent with experimental $J/\psi$ data. $\kappa$ is factor of $\sim$3 larger than in lattice QCD calculations.