Nucleon shadowing effects in Cu+Cu and Au+Au collisions at RHIC within the HIJING code

الأصل · EN

The centrality dependence of pseudorapidity density of charged particles (dNch/dη) in Cu+Cu (Au+Au) collisions at RHIC energy of √s NN=22.4, 62.4 and 200 (19.6, 62.4 and 200) GeV, is investigated within an improved HIJING code. The standard HIJING model is enhanced by a prescription for collective nucleon-nucleon (NN) interactions and more modern parton distribution functions. The collective NN-interactions are used to induce both cascade and nucleon shadowing effects. We find collective cascade broadens the pseudorapidity distributions in the tails (at |η|> y beam) above 25-30% collision centrality to be consistent with the dNch/dη data at √s NN=19.6, 22.4, 62.4 GeV. The overall contribution of nucleon shadowing is shown to depress the whole shape of dNch/dη in the primary interaction region (at |η|< y beam) for semiperipheral (20-25 %) and peripheral (≥ 35-40%) Cu+Cu (Au+Au) interactions at √s NN=200 GeV, in accordance with the PHOBOS data.