Azimuthal anisotropy ($v_{2}$) of high-p$_{T}$ $\pi^{0}$ and direct $\gamma$ in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

Understand

Preliminary results from the STAR collaboration of the azimuthal anisotropy $(v_{2})$ of $\pi^{0}$ and direct photon ($\gamma_{dir}$) at high transverse momentum (p$_{T}$) from Au+Au collisions at center-of-mass energy $\sqrt{s_{_{NN}}}=200$~GeV are presented.

• A shower-shape analysis is used to select a sample free of direct photons ($\pi^0$) and a sample rich in direct photons $\gamma_{rich}$.
• The relative contribution of background in the $\gamma_{rich}$ sample is determined assuming no associated charged particles nearby $\gamma_{dir}$.
• The $v_{2}$ of direct photons ($v_{2}^{\gamma_{dir}}$) at mid-rapidity ($|\eta^{\gamma_{dir}}|<1$) and high p$_{T}$ ($8< p_{T}^{\gamma_{dir}}<16$~GeV/$c$) is extracted from those of $\pi^{0}$ and neutral particles measured in the same kinematic range.