Leading Order Pqcd Hadron Production and Nuclear Modification Factors at Rhic and the Lhc

Abstract Hadron production in leading order pQCD is reviewed. The shape of the single inclusive particle spectra is well described for pT ≥ 2 − 3 GeV at center of mass energies from 20 GeV to 2 TeV. The phenomenological K-factor is found to decrease systematically with √ s. For ultra-relativistic heavy ion reactions the calculation is augmented with the effects of initial multiple parton scattering and final state radiative energy loss. Baseline CERN-LHC predictions for hadron production in p + p and suppression in central Pb + Pb reactions at √ s = 5.5 TeV are given in comparison to the corresponding results at BNLRHIC and CERN-SPS energies.