${\rho }^0$-vector meson elliptic flow ($v_2$) in $Au+Au$ collisions at $\sqrt{s_{NN}}=200$ GeV in STAR at RHIC

The first measurement of the ${\rho }^0$ - vector meson elliptic flow $v_2$ at mid-rapidity ($\mathrm{\mid }y\mathrm{\mid }$ $<$ 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.