Review of the theoretical heavy-ion physics

TL;DR

This paper reviews theoretical models used in heavy-ion collision physics, comparing their successes and challenges across a wide energy range, and discusses transport coefficients in relation to lattice QCD results.

Contribution

It provides a comprehensive overview of various theoretical approaches and their alignment with experimental data in heavy-ion physics, highlighting current issues and future directions.

Findings

Statistical models successfully describe certain particle yields.

Hydrodynamic models capture collective flow phenomena.

Transport coefficients are consistent with lattice QCD calculations.

Abstract

In this contribution we briefly give an overview of the theoretical models used to describe experimental data from heavy-ion collisions from $\sqrt{s_{NN}} \approx $ 4 GeV to ultra-relativistic energies of $\sqrt{s_{NN}} \approx $ 5 TeV. We highlight the successes and problems of statistical or hadron-resonance gas models, address the results of macroscopic approaches like hydrodynamics (in different hybrid combinations) as well as the results from microscopic transport approaches in comparison to experimental data. Finally, the transport coefficients like shear $\eta$ and bulk viscosity $\zeta$ - entering the macroscopic models - are confronted with results from lattice QCD in thermal equilibrium for vanishing chemical potential.