Modified fragmentation function in heavy ion collisions at RHIC via direct gamma-jet measurements

作者：Hamed A M^*

来源：European Physical Journal C, 2009, 61(4): 597-601.

DOI：10.1140/epjc/s10052-009-0960-z

The presented results are the first measurements at RHIC for direct gamma-charged hadron azimuthal correlations in heavy ion collisions. We use these correlations to study the color charge density of the medium through the medium-induced modification of high-p(T) parton fragmentation. Azimuthal correlations of direct photons at high transverse energy (8 < p(T) < 16 GeV) with away-side charged hadrons of transverse momentum (3 < p(T) < 6 GeV/c) have been measured over a broad range of centrality for Au Au collisions and p p collisions at root s(NN) = 200 GeV in the STAR experiment. A transverse shower shape analysis in the STAR Barrel Electromagnetic Calorimeter Shower Maximum Detector is used to discriminate between the direct photons and photons from the decays of high p(T) pi(0). The per-trigger away-side yield of direct gamma is smaller than from pi(0) trigger at the same centrality class. Within the current uncertainty the I(CP) of direct gamma and pi(0) are similar.

• 出版日期2009-6