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

TL;DR

This study measures the elliptic flow of multi-strange hadrons in Au+Au collisions at 200 GeV, revealing strong partonic collectivity and mass ordering effects influenced by late hadronic interactions.

Contribution

It provides new experimental evidence of partonic collectivity and mass ordering breaking in heavy-ion collisions at RHIC energies.

Findings

Strange hadron $v_2$ similar to lighter hadrons, indicating strong quark flow.

Mass ordering of $v_2$ breaks between $\,phi$ and proton at low $p_T$.

Evidence for partonic collectivity at top RHIC energy.

Abstract

We present recent results of the mid-rapidity elliptic flow ($v_2$) for multi-strange hadrons and the $\phi$ meson as a function of centrality in Au + Au collisions at the center of mass energy $\sqrt{s_{NN}}$ = 200 GeV. The transverse momentum dependence of $\phi$ and $\Omega$ $v_2$ is similar to that of pion and proton, indicating that the heavier strange ($s$) quark flows as strongly as the lighter up ($u$) and down ($d$) quarks. These observations constitute a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. In addition, the mass ordering of $v_2$ breaks between the $\phi$ and proton at low transverse momenta in the 0-30\% centrality bin, possibly due to the effect of late hadronic interactions on the proton $v_2$.