Initial state anisotropies and their uncertainties in ultrarelativistic heavy-ion collisions from the Monte Carlo Glauber model

TL;DR

This paper reviews how initial spatial anisotropies in ultrarelativistic heavy-ion collisions are modeled using the Monte Carlo Glauber approach, focusing on uncertainties from nucleon interactions and correlations, which are crucial for interpreting experimental data.

Contribution

It provides a detailed analysis of uncertainties in initial-state anisotropies due to modeling choices in the Monte Carlo Glauber model, including nucleon interaction profiles and correlations.

Findings

Differences between black disk and probabilistic profile models impact anisotropy calculations.

Nucleon-nucleon correlations significantly influence initial-state anisotropies.

Uncertainties in modeling affect the extraction of QCD matter properties.

Abstract

In hydrodynamical modeling of heavy-ion collisions, the initial-state spatial anisotropies are translated into momentum anisotropies of the final-state particle distributions. Thus, understanding the origin of the initial-state anisotropies and their uncertainties is important before extracting specific QCD matter properties, such as viscosity, from the experimental data. In this work we review the wounded nucleon approach based on the Monte Carlo Glauber model, charting in particular the uncertainties arising from modeling of the nucleon-nucleon interactions between the colliding nucleon pairs and nucleon-nucleon correlations inside the colliding nuclei. We discuss the differences between the black disk model and a probabilistic profile function approach for the inelastic nucleon-nucleon interactions, and investigate the influence of initial-state correlations using state-of-the-art modeling of these.