Elliptic flow of light nuclei in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

Abstract

We present the elliptic flow ($v_{2}$) of light nuclei at mid-rapidity in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. The results are measured in the STAR experiment at RHIC. The $v_{2}$ measurement for light nuclei as a function of transverse momentum $p_{T}$ is found to follow an approximate atomic mass number ($A$) scaling. We compare the measured nuclei $v_{2}$ to results from a dynamical coalescence model calculation. The $v_{2}$ values for light nuclei are further scaled to the number of constituent quarks (NCQ) of their constituent nucleons and are consistent with NCQ scaled $v_{2}$ for baryons and mesons. The dominance of partonic collectivity in the transverse expansion dynamics in these collisions naturally produces such a consistent picture. Similar to other hadrons, an increase of $p_{T}$-integrated $v_{2}$ scaled by the participant eccentricity as a function of collision centrality has been observed.