Correlation of high energy photons and charged particles in p+p and d+Au collisions at $\sqrt{s}=200$ GeV

Abstract

Azimuthal correlations between high energy photons from $\pi^0$ decay ($p_T^{\gamma} < 10.5$ GeV) and charged hadrons ($p_T^{hadron}$ above a threshold of 2, 3 or 4 GeV/c) have been measured in p+p and d+Au collisions at $\sqrt{s}=200$ GeV. Clear jet-like correlations are observed at $\Delta\phi=0$ and 180 degrees, with peak widths decreasing with increasing $p_T^{hadron}$. Jet $<j_T>$ and $\sqrt{< k_T^2 >}$ in d+Au collisions are deduced from the distributions. {\it These results are presented in Quark Matter 2004 poster session.