Energy dependence of heavy-ion initial condition in isobar collisions

TL;DR

This study uses transport models to analyze how energy affects the initial conditions in isobar heavy-ion collisions, revealing different sources of flow and their energy dependence.

Contribution

It identifies independent sources of eccentricities affecting flow and explores their energy dependence in isobar collisions using transport simulations.

Findings

Different sources of eccentricities contribute to flow.

Flow generation efficacy varies among sources.

Significant flow component is dynamically generated during evolution.

Abstract

Collisions of isobar nuclei, those with the same mass number but different structure parameters, provide a new way to probe the initial condition of the heavy ion collisions. Using transport model simulation of $^{96}$Ru+$^{96}$Ru and $^{96}$Zr+$^{96}$Zr collisions at two energies $\sqrt{s_{\mathrm{NN}}}=0.2$ TeV and 5.02 TeV, where $^{96}$Ru and $^{96}$Zr nuclei have significantly different deformations and radial profiles, we identify sources of eccentricities contributing independently to the final state harmonic flow $v_n$. The efficacy for flow generation differs among these sources, and explains the modest energy dependence of the isobar ratios of $v_n$. Additionally, a significant component of $v_n$ is found to be uncorrelated with the eccentricity but is instead generated dynamically during system evolution. Experimental measurement of these ratios at the LHC energy and comparison with RHIC energy can provide insight into the collision-energy dependence of the initial condition.