Charged Multiplicity Density and Number of Participant Nucleons in Relativistic Nuclear collisons

摘要

The energy and centrality dependencies of charged particle pseudorapidity density in relativistic nuclear collisions were studied using a hadron and string cascade model,JPCIAE.Both the relativistic p+P-experimental data and the PHOBOS and PHENIX Au+Au data at RHIC energy could be fairly reproduced within the framework of JPCIAE model and without retuning the model parameters.The predictions for Pb+Pb collisions at the LHC energy were also given.We computed the participant nucleon distributions using different methods.It was found that the number of participant nucleons is not a well defined variable both experimentally and theoretically.Thus it may be inappropriate to use the charged particle pseudorapidity density per participant pair as a function of the number of participant nucleons for distinguishing various theoretical models.