Measurement of inclusive $J/\psi$ production in Au+Au collisions at $\sqrt{s_\mathrm{NN}} = 54.4$ GeV at STAR

TL;DR

This study measures inclusive $J/$ production in Au+Au collisions at 54.4 GeV, revealing suppression patterns consistent with models including dissociation and regeneration, and compares these results across different collision energies.

Contribution

First measurement of $J/$ production at 54.4 GeV in Au+Au collisions, providing new data to test energy dependence of suppression and refine theoretical models.

Findings

Observed $J/$ suppression relative to $p$+$p$ collisions.

No significant energy dependence of suppression between 17.3 and 200 GeV.

Transport models with dissociation and regeneration agree with data.

Abstract

This article presents measurements of inclusive $J/\psi$ production at midrapidity ($\left|y\right| <$ 1.0) in Au+Au collisions at $\sqrt{s_\mathrm{NN}} = 54.4$ GeV with the STAR detector at the Relativistic Heavy Ion Collider. A suppression of the $J/\psi$ yield, quantified using the nuclear modification factors ($R_{\mathrm{AA}}$, $R_{\mathrm{CP}}$), is observed with respect to the scaled production in $p$+$p$ collisions. The dependence of $R_{\mathrm{AA}}$ on collision centrality and $J/\psi$ transverse momentum is measured with improved precision compared to previous measurements at 39 and 62.4 GeV, while the centrality dependence of $R_{\mathrm{CP}}$ is measured and compared to the same results at 39, 62.4, and 200 GeV. In central collisions, no significant collision energy dependence of $R_{\mathrm{AA}}$ is found within uncertainties for collision energies between 17.3 and 200 GeV. Two transport model calculations that include dissociation and regeneration contributions are consistent with the experimental results within uncertainties. Although no significant collision energy dependence of the $J/\psi$ suppression in high energy heavy-ion collisions up to $\sqrt{s_\mathrm{NN}} = 200$ GeV is observed within uncertainties, the newly measured results at 54.4 GeV Au+Au collisions provide additional constraints on theoretical calculations of the hot medium evolution and cold nuclear matter effects.