A description of pseudorapidity distributions of charged particles produced in Au+Au collisions at RHIC energies

TL;DR

This paper models the pseudorapidity distributions of charged particles in high-energy Au+Au collisions at RHIC, highlighting the importance of leading particles and hydrodynamic expansion with phase transition.

Contribution

It introduces a combined hydrodynamic and Gaussian leading particle model to describe charged particle distributions at RHIC energies, emphasizing the role of leading particles.

Findings

Leading particles are essential at high energies.

Hydrodynamic expansion with phase transition fits the data.

Nuclear transparency varies with energy.

Abstract

The charged particles produced in heavy ion collisions consist of two parts: One is from the freeze-out of hot and dense matter formed in collisions. The other is from the leading particles. In this paper, the hot and dense matter is assumed to expand according to the hydrodynamic model including phase transition and decouples into particles via the prescription of Cooper-Frye. The leading particles are as usual supposed to have Gaussian rapidity distributions with the number equaling that of participants. The investigations of this paper show that, unlike low energy situations, the leading particles are essential in describing the pseudorapidity distributions of charged particles produced in high energy heavy ion collisions. This might be due to the different transparencies of nuclei at different energies.