Speaker
Description
Directed and elliptic flow, $v_1$ and $v_2$, are sensitive to dynamics of heavy-ion collisions at the early stage of the system evolution and equation of state of the medium. The hadronic interaction cross sections of multi-strange hadrons and $\phi$ mesons are expected to be small and their freeze-out temperatures are close to the quark-hadron transition temperature. Hence, these hadrons may provide information primarily from the early stage of the high energy collisions and are important for the study of QCD phase diagram at RHIC.
In the first phase of RHIC beam energy scan (BES-I), we observed that $v_{1}$ slopes ($dv_{1}/dy$) at mid-rapidity region for net-proton and net-$\Lambda$ show a minimum value when the collision energy is around $\sqrt{s_{NN}}$ = 10 - 20 GeV [1]. The $v_2$ of $\phi$ mesons seems lower than those of other particles at $\sqrt{s_{NN}}$ = 7.7 and 11.5 GeV [2]. In this poster, with large statistics from the STAR fixed-target (FXT) and second phase of RHIC beam energy scan (BES-II), we will present precise measurements on $v_1$ and $v_2$ of $K^\pm$, $K_S^0$, $\Lambda$, $\bar{\Lambda}$, $\Xi$, $\bar{\Xi}^{+}$, $\Omega$, $\bar{\Omega}^{+}$, and $\phi$ mesons in Au+Au collisions at $\sqrt{s_{NN}}$ = 3 - 19.6 GeV from STAR.
[1] L. Adamczyk $\textit{et al.}$, Phys. Rev. Lett. $\textbf{120}$, 062301 (2018).
[2] L. Adamczyk $\textit{et al.}$, Phys. Rev. Lett. $\textbf{110}$, 142301 (2013).
