The elliptic flow of multi-strange hadrons in $\sqrt{s_{NN}}$ = 200 GeV Au + Au collisions at STAR

The measurement of the elliptic flow, $v_2$, provides a powerful tool for studying the properties of hot and dense medium created in high-energy nuclear collisions. We present the measurement of $v_2$ of multi-strange hadrons ($\varphi$, $\mathrm{\Xi }$ and $\mathrm{\Omega }$) in $\sqrt{s_{NN}}$= 200 GeV Au + Au collisions at STAR. In minimum-bias Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV, a significant amount of elliptic flow, almost identical to other mesons and baryons, is observed for multi-strange hadrons. Experimental observations of $p_T$ dependence of $v_2$ of identified particles at RHIC support partonic collectivity. We also discuss the possible breaking of mass ordering of the $\varphi$ mesons in the low $p_T$ region.