Elliptic flow of strange and multi-strange hadrons in isobar collisions at $\sqrt{s_{\mathrm{NN}}}=200\mathrm{GeV}$ at RHIC

Abstract

We report a systematic measurement of elliptic flow ($v_2$) of $K_s^0$, $\Lambda$, $\overline{\Lambda }$, $\varphi$, ${\Xi }^{-}$, ${\overline{\Xi }}^{+}$, and ${\Omega }^{-}$+${\overline{\Omega }}^{+}$ at mid-rapidity ($|y|<1.0$) for isobar, ${}_{44}^{96}$Ru+${}_{44}^{96}$Ru and ${}_{40}^{96}$Zr+${}_{40}^{96}$Zr, collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. The transverse momentum ($p_{\mathrm{T}}$) dependence of $v_2$ is studied for various centrality classes. The number of constituent quark scaling of (multi-)strange hadrons is found to hold approximately within 20%, suggesting the development of partonic collectivity in isobar collisions similar to that observed in Au+Au collisions at $\sqrt{s_{\mathrm{NN}}}$ = 200 GeV. The average $v_2$ ratio shows $\sim$2% deviation from unity in central and mid-central collisions for strange hadrons, indicating a difference in nuclear structure and deformation between the isobars. The $v_2$ in isobaric collisions is compared to Cu+Cu, Au+Au, and U+U collisions at similar collision energies. We observe an increase in $v_2(p_{\mathrm{T}})$ with increasing system size. The difference in $v_2$ between the isobar and other collision systems increases with $p_{\mathrm{T}}$. The results are compared with a multi-phase transport model calculations with a deformed density profile to provide further insight into the nuclear structure of these isobars.

Comments: 13 pages, 14 figures