Centrality and transverse momentum dependence of elliptic flow of multi-strange hadrons and $\ddot{I}•$ meson in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

Abstract

We present high precision measurements of elliptic flow near midrapidity ($|y|<1.0$) for multi-strange hadrons and $\ddot{I}•$ meson as a function of centrality and transverse momentum in Au+Au collisions at center of mass energy $\sqrt{s_{NN}}=$ 200 GeV. We observe that the transverse momentum dependence of $\ddot{I}•$ and $\hat{I}\text{c◯}$ $v_2$ is similar to that of $\ddot{I}€$ and $p$, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0-30$\%$ and 30-80$\%$ collision centrality. There is an indication of the breakdown of previously observed mass ordering between $\ddot{I}•$ and proton $v_2$ at low transverse momentum in the 0-30$\%$ centrality range, possibly indicating late hadronic interactions affecting the proton $v_2$.

7 pages and 4 figures, Accepted for publication in Physical Review Letters