Detecting nuclear mass distribution in isobar collisions via charmonium

TL;DR

This study uses relativistic transport simulations to analyze $J/\psi$ production in isobar collisions, revealing that charmonium yields and flow are sensitive to nucleon distribution differences, offering a new probe for nuclear structure.

Contribution

The paper introduces the use of $J/\psi$ production and elliptic flow as novel probes to distinguish nucleon distributions in isobar nuclei through transport model comparisons.

Findings

$J/\psi$ yield ratio is sensitive to collision geometry and medium evolution.

Elliptic flow $v_2$ of $J/\psi$ differs from light hadrons and depends on medium evolution.

Charmonium production provides an independent method to study nucleon distributions.

Abstract

The collective properties of final state hadrons produced in the high statistics $_{44}^{96}$Ru+$_{44}^{96}$Ru and $_{40}^{96}$Zr+$_{40}^{96}$Zr collisions at $\sqrt{s_\mathrm{NN}} = 200~\mathrm{GeV}$ are found to be significantly different. Such differences were argued to be precise probes of the difference in nucleon distribution in the isobar nuclei. We investigate the $J/\psi$ production in the isobar collision via a relativistic transport approach. By comparing the isobar systems according to equal centrality bin and equal multiplicity bin, we find that the yield ratio of $J/\psi$ is sensitive to the differences in both the number of binary collisions and the medium evolution. Besides, the elliptic flow $v_2$ of $J/\psi$ is qualitatively different from the light hadrons, and the ratio between Ru+Ru and Zr+Zr collisions is sensitive to the medium evolution. The charmonium production provides an independent probe to study the nucleon distribution in the isobar system.