Probing nuclear structure using elliptic flow of strange and multi-strange hadrons in isobar collisions

TL;DR

This study measures the elliptic flow of strange and multi-strange hadrons in isobar collisions at RHIC to understand initial state anisotropies and nuclear structure effects, providing insights into the Chiral Magnetic Effect.

Contribution

It presents the first detailed elliptic flow ($v_{2}$) measurements of various strange hadrons in Ru+Ru and Zr+Zr collisions, testing nuclear structure models and NCQ scaling.

Findings

Differences in $v_{2}$ between Ru+Ru and Zr+Zr collisions reveal nuclear structure effects.

System size dependence of $v_{2}$ observed across Cu+Cu, Au+Au, and U+U collisions.

Transport models compared to data to constrain nuclear structure parameters.

Abstract

Isobar collisions, $^{96}_{44}$Ru+$^{96}_{44}$Ru and $^{96}_{40}$Zr+$^{96}_{40}$Zr, at $\sqrt{s_{\mathrm {NN}}}$ = 200 GeV have been performed at RHIC in order to study the charge separation along the magnetic field, called the Chiral Magnetic Effect (CME). The difference in nuclear deformation and structure between the two isobar nuclei may result in a difference in the flow magnitudes. Hence, elliptic flow measurements for these collisions give direct information about the initial state anisotropies. Strange and multi-strange hadrons have a small hadronic cross-section compared to light hadrons, making them an excellent probe for understanding the initial state anisotropies of the medium produced in these isobar collisions. The collected datasets include approximately two billion events for each of the isobar species and provide a unique opportunity for statistics hungry measurements. In this proceeding, we will report the elliptic flow ($v_{2}$) measurement of $K_{s}^{0}$, $\Lambda$, $\overline{\Lambda}$, $\phi$, $\Xi^{-}$, $\overline{\Xi}^{+}$, $\Omega^{-}$, and $\overline{\Omega}^{+}$ at mid-rapidity for Ru+Ru and Zr+Zr collisions at $\sqrt{s_{\mathrm {NN}}}$ = 200 GeV. The centrality and transverse momentum ($p_{T}$) dependence of $v_{2}$ of (multi-)strange hadrons will be shown. System size dependence of $v_{2}$ will be shown by comparing the $v_{2}$ results obtained from Cu+Cu, Au+Au, and U+U collisions. The number of constituent quark (NCQ) scaling for these strange hadrons will also be tested. We will also compare the $p_{T}$-integrated $v_{2}$ for these two isobar collisions. Transport model calculations will be compared to data to provide further quantitative constraints on the nuclear structure.