Cold nuclear modifications at RHIC and LHC

Abstract

We use recent nuclear parton distributions, among them the Hirai - Kumano - Nagai (HKN) and Eskola - Paukkunen - Salgado (EPS08) parameterizations, in our pQCD-improved parton model to calculate the nuclear modification factor, R-AA. (p(T)), at RHIC and at the LHC. At RHIC, the deuteron-gold nuclear modification factor for pions, measured at p(T) >= 10 GeV/c in central collisions, appears to deviate more from unity than the model results. The slopes of the calculated R-dAu(p(T)) are similar to the slopes of the PHENIX pion and photon data. At LHC, without final-state effects we see a small enhancement of R-dPb(p(T)) in the transverse momentum range 10 GeV/c >= p(T) >= 100 GeV/c for most parameterizations. The inclusion of final-state energy loss will reduce the R-dPb(p(T))values.