$\rho^{0}$-vector meson elliptic flow ($v_{2}$) in $Au+Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV in STAR at RHIC

Abstract

The first measurement of the $\rho^{0}$ - vector meson elliptic flow $v_{2}$ at mid-rapidity ($|y |$ $<$ 0.5) in $40 - 80$ $%$ centrality in $Au+Au$ collisions at $\sqrt{s_{NN}} = 200$ GeV from the STAR experiment at RHIC is presented. The study is through the $\pi^{+} \pi^{-}$ hadronic decay channel of $\rho^{0}$ which has a branching ratio of $\sim$ 100 %. The analysis is being carried out in two different methods. The $v_{2}$ results obtained in these methods are consistent. Number of Constituent Quark (NCQ) scaling of $v_{2}$ of $\rho^{0}$ meson with respect to other hadrons at intermediate $p_{T}$ is observed. The $\rho^{0}$ $v_{2}$ favors $NCQ = 2$ scaling, supporting the coalescence being the dominant mechanism of hadronization in the intermediate $p_{T}$ region at RHIC.