Two-body nucleon-nucleon correlations in Glauber models of relativistic heavy-ion collisions

TL;DR

This study examines how central two-body nucleon-nucleon correlations influence key fluctuation measures in relativistic heavy-ion collisions, finding that such correlations significantly affect these observables and can be effectively modeled with simple repulsion assumptions.

Contribution

It demonstrates that two-body nucleon-nucleon correlations impact fluctuation measures in heavy-ion collisions and shows that simple hard-core repulsion models suffice for these analyses.

Findings

Correlation effects are about 10-20% on fluctuation measures.

Realistic Gaussian correlations are similar to hard-core repulsion models.

Hard-core repulsion models are sufficient for current fluctuation analyses.

Abstract

We investigate the influence of the central two-body NN correlations on several quantities observed in relativistic heavy-ion collisions. It is demonstrated with explicit Monte Carlo simulations, that the basic correlation measures, such as the fluctuations of participant eccentricity, initial size fluctuations, or the fluctuations of the number of sources producing particles, are all sensitive to the inclusion of the two-body correlations. The effect is at the level of about 10-20%. Moreover, the realistic (Gaussian) correlation function gives indistinguishable results from the hard-core repulsion, with the expulsion distance set to 0.9 fm. Thus, for investigations of the considered correlation measures, it is sufficient to use the Monte Carlo generators accounting for the hard-core repulsion.