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

Abstract

The centrality dependence of pseudorapidity density of charged particles () in Cu + Cu (Au + Au) collisions at Relativistic Heavy Ion Collider energy of , 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 ) above 25%–30% collision centrality to be consistent with the data at . The overall contribution of nucleon shadowing is shown to depress the whole shape of in the primary interaction region (at ) for semiperipheral (20%–25%) and peripheral () Cu + Cu (Au + Au) interactions at , in accordance with the PHOBOS data.