Predictions for isobaric collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV from a multiphase transport model

TL;DR

This study uses a multiphase transport model to predict charged-particle observables and CME signals in Ru + Ru and Zr + Zr collisions at 200 GeV, finding small differences in bulk observables but robust CME signal differences.

Contribution

It introduces a method to predict CME signals in isobaric collisions and assesses the impact of nuclear structure parametrizations on observables.

Findings

Small differences in $dN/d\u03b7$, $p_T$ spectra, and $v_2$ between the isobaric collisions.

CME signal differences are robust and insensitive to final-state interactions.

The initial charge separation proportional to magnetic field effectively models CME signals.

Abstract

The isobaric collisions of $^{96}_{44}$Ru + $^{96}_{44}$Ru and $^{96}_{40}$Zr + $^{96}_{40}$Zr have recently been proposed to discern the charge separation signal of the chiral magnetic effect (CME). In this article, we employ the string melting version of a multiphase transport model to predict various charged-particle observables, including $dN/d\eta$, $p_T$ spectra, elliptic flow ($v_2$), and particularly possible CME signals in Ru + Ru and Zr + Zr collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV. Two sets of the nuclear structure parametrization have been explored, and the difference between the two isobaric collisions appears to be small, in terms of $dN/d\eta$, $p_T$ spectra, and $v_2$ for charged particles. We mimic the CME by introducing an initial charge separation that is proportional to the magnetic field produced in the collision, and study how the final-state interactions affect the CME observables. The relative difference in the CME signal between the two isobaric collisions is found to be robust, insensitive to the final-state interactions.