First order event plane correlated directed and triangular flow in Au+Au collisions from BES-II at STAR

Department of Physics, The Ohio State University, 191 W Woodruff Ave, Columbus, OH 43210

^* e-mail: liu.6566@osu.edu

Published online: 26 June 2024

Abstract

In heavy-ion collisions, the measurements of anisotropic flow coefficients (v_n) offer insights into collective hydrodynamic expansion and transport properties of the produced medium at higher collision energies, while also being sensitive to the compressibility of the nuclear matter and nuclear equation of state at lower collision energies. In this contribution, we present the measurement of charged particle v₁ over ten units of pseudorapidity (η) in Au+Au collisions at √S_NN = 27 and 19.6 GeV and compare it with multiple model calculations. Only UrQMD was able to reproduce a sizable v₁ at the forward pseudorapidity as observed in the experiment. We also present the results of v₁ and v₃ at √S_NN = 3 - 3.9 GeV for identified hadrons and light nuclei with respect to Ψ₁. The results are compared with theoretical models to identify the source of nonzero v₃{Ψ₁} and to demonstrate its vital connection to the equation of state.