Gamma-Jet Tomography of Quark-Gluon Plasma in High-Energy Nuclear Collisions
arXiv:0907.4816 · doi:10.1016/j.nuclphysa.2009.10.037
Abstract
Within the next-to-leading order (NLO) perturbative QCD (pQCD) parton model, suppression of away-side hadron spectra associated with a high $p_{T}$ photon due to parton energy loss is shown to provide a complete tomographic picture of the dense matter formed in high-energy heavy-ion collisions at RHIC. Dictated by the shape of the $γ$-triggered jet spectrum in NLO pQCD, hadron spectra at large $z_T=p_T^{h}/p_T^γ \stackrel{>}{\sim} 1$ are more susceptible to parton energy loss and therefore are dominated by surface emission of $γ$-triggered jets, whereas small $z_{T}$ hadrons mainly come from fragmentation of jets with reduced energy from volume emission. These lead to different centrality dependence of the hadron suppression in different regions of $z_{T}$.
4 pages, 3 figures, proceedings for QM 2009 conference