Two-body nucleon-nucleon correlations in Glauber-like models

TL;DR

This paper examines how central two-body nucleon-nucleon correlations influence key observables in relativistic heavy-ion collisions, finding that realistic correlations slightly alter fluctuation measures and that more realistic wounding profiles reduce eccentricity and fluctuations, impacting elliptic flow studies.

Contribution

It demonstrates that realistic two-body correlations have minimal impact on fluctuation measures and compares different wounding profiles, highlighting their effects on collision geometry.

Findings

Realistic correlations are similar to hard-core repulsion with 0.9 fm expulsion distance.

Gaussian wounding profiles reduce eccentricity and fluctuations.

Fluctuation measures are sensitive at 10-20% to two-body correlations.

Abstract

We investigate the role of the central two-body nucleon-nucleon correlations on typical quantities observed in relativistic heavy-ion collisions. Basic correlation measures, such as the fluctuations of the participant eccentricity, initial size fluctuations, or the fluctuations of the number of sources producing particles, are sensitive at the level 10-20% to the inclusion of the two-body correlations. However, the realistic correlation function gives virtually indistinguishable results from the {\em hard-core repulsion} with the expulsion distance set to $\sim 0.9$ fm. In the second part of the talk we compare the spherical and Gaussian wounding profiles and find that the latter, which is more realistic, leads to reduced eccentricity and fluctuations. This has significance for precision studies of the elliptic flow.