Elliptic ($v_2$) and triangular ($v_3$) anisotropic flow of identified hadrons from the STAR Beam EnergyScan program

TL;DR

This paper reports measurements of elliptic and triangular flow coefficients for identified hadrons in Au+Au collisions across various energies, revealing patterns consistent with flow phenomena and providing data to constrain theoretical models of quark-gluon plasma properties.

Contribution

It presents new measurements of $v_3$ for identified hadrons over a range of energies, extending understanding of flow patterns and their energy dependence in heavy-ion collisions.

Findings

Triangular flow ($v_3$) shows mass ordering at low $p_T$.

Meson/baryon splitting observed at intermediate $p_T$.

Differences in flow between protons and antiprotons are noted.

Abstract

Elliptic ($v_2$) and triangular ($v_3$) anisotropic flow coefficients for inclusive and identified charged hadrons (~$\pi^\pm$, $K^\pm$, $p$, $\bar{p}$~) at midrapidity in Au+Au collisions, measured by the STAR experiment in the Beam Energy Scan (BES) at the Relativistic Heavy Ion Collider at $\sqrt{s_{NN}}$ = $11.5$ - $62.4$ GeV, are presented. We observe that the triangular flow signal ($v_3$) of identified hadrons exhibits similar trends as first observed for $v_2$ in Au+Au collisions, i.e. (i) mass ordering at low transverse momenta, $p_T < 2$ GeV/c, (ii) meson/baryon splitting at intermediate $p_T$, $2< p_T < 4$ GeV/c, and (iii) difference in flow signal of protons and antiprotons. New measurements of $v_3$ excitation function could serve as constraints to test different models and to aid new information about the temperature dependence of the transport properties of the strongly interacting matter.