Anisotropic Flow of Identified Particles in Au + Au Collisions at $\sqrt{s_{NN}}$ = 3-3.9 GeV at RHIC

Abstract

In these proceedings, we present transverse momentum dependence of the mid-rapidity slope of directed flow ($dv_1/dy|_{y=0}$) for $\pi^+$ and $K_S^0$ in Au + Au collisions at $\sqrt{s_{NN}}$ = 3.0, 3.2, 3.5, and 3.9 GeV. Both $\pi^+$ and $K_S^0$ show negative $v_1$ slope at low $p_T$ ($p_T < 0.6$ GeV/$c$). Collision energy dependence of $v_1$ slope and $p_T$-integrated $v_2$ for $\pi^{\pm}$, $K_S^0$, and $\Lambda$ are also presented. A comparison to JAM model calculations indicates that spectator shadowing can lead to anti-flow at low $p_T$. In addition, a breaking of the Number of Constitute Quark (NCQ) scaling of elliptic flow ($v_2$) is observed at $\sqrt{s_{NN}}$ = 3.2 GeV, which implies the dominance of hadronic degrees of freedom occurs in collisions at $\sqrt{s_{NN}}$ = 3.2 GeV and below.