Production at High $p_T$ in Central Au+Au and $p+p$ collisions at $\sqrt{s_{_{NN}}} = 200$ GeV in STAR

Abstract

he $\rho^0$ production at high-$p_T$ (5.0 $\leq p_T \leq$ 10.0 GeV/$c$) measured in minimum bias $p+p$, Au+Au and central Au+Au collisions in the STAR detector are presented. The $\rho^0/\pi$ ratio measured in $p+p$ is compared to PYTHIA calculations as a test of perturbative quantum chromodynamics (pQCD) that describes reasonably well particle production from hard processes. The $\rho^0$ nuclear modification factor are also presented. In $p+p$ collisions, charged pions and (anti-)protons are measured in the range 5.0 $\leq p_T \leq$ 15.0 GeV/$c$ and the anti-particle to particle ratio and the baryon to meson ratios of these hadrons are discussed.