Initial conditions for nuclear collisions: theory overview

TL;DR

This paper reviews recent theoretical advances in modeling initial conditions of ultra-relativistic nucleus-nucleus collisions, focusing on fluctuations, rapidity dependence, and the evolution of the quark-gluon plasma.

Contribution

It provides a comprehensive overview of new developments in initial condition modeling, including sub-nucleonic fluctuations and non-boost-invariant approaches.

Findings

Enhanced understanding of sub-nucleonic fluctuations

Development of models with rapidity-dependent initial conditions

Insights into the evolution and matching of initial stages

Abstract

We overview the current status and recent developments on initial conditions in ultra-relativistic nucleus-nucleus collisions. Specifically, we look at the progress in understanding the role of sub-nucleonic fluctuations in large and small collision systems. Next, we review the current ideas of going beyond boost invariant initial conditions and introducing physically motivated rapidity fluctuations at RHIC and LHC energies. Finally, we discuss the time evolution of initial stages and the matching between different descriptions of the QGP.