A perturbative QCD analysis of charged-particle distributions in hadronic and nuclear collisions Original Research Article

We compute the distributions of charged particles at large transverse momenta in View the MathML source, pA and AA collisions in the framework of perturbative QCD, by using collinear factorization and the modern PDFs and fragmentation functions. At the highest cms-energies the shape of the spectra measured in View the MathML source collisions at large View the MathML source can be well explained. The difference between the data and the lowest-order computation is quantified in terms of a constant K-factor for each energy. The K-factor is found to systematically decrease with growing View the MathML source. Also a lower limit for the partonic transverse momentum, View the MathML source, is extracted for each View the MathML source based on the comparison with the measurements. A systematic increase of View the MathML source as a function of View the MathML source is found. Nuclear effects in the charged-particle spectra in pA and AA collisions at RHIC and LHC are studied in the framework of collinear factorization by applying the EKS98 nuclear corrections to the parton distributions. The nuclear effects are shown to mostly enhance the computed spectra. A comparison with the recent PHENIX data from central and peripheral Au+Au collisions at RHIC is done.