What is the Quark-Gluon Plasma made of?

TL;DR

This review summarizes current theoretical and experimental insights into the internal structure of the quark-gluon plasma at high temperatures, highlighting approaches like lattice QCD and heavy ion collision data.

Contribution

It provides a comprehensive overview of both perturbative and nonperturbative methods used to understand quark-gluon plasma structure and discusses recent experimental findings.

Findings

Insights from lattice QCD and effective theories.

Analysis of bulk observables and hard probes.

Future research directions outlined.

Abstract

This article surveys our present understanding of the internal structure of the fully developed quark-gluon plasma at temperatures outside the crossover region. The theoretical part of the review covers perturbative and nonperturbative approaches to quark-gluon plasma structure, in particular, hard-thermal loop effective theory, lattice QCD and the functional renormalization group. The phenomenological part of the review scrutinizes the information that has been derived from bulk observables and hard probes in relativistic heavy ion collisions in terms of how it informs our knowledge about the structure of the quark-gluon plasma. The final section lists possible avenues for future progress.