Collective dynamics of heavy ion collisions in ATLAS

TL;DR

This paper presents recent measurements of collective phenomena in various collision systems at the LHC, providing insights into the initial state and structure of quark-gluon plasma through flow correlations and decorrelations.

Contribution

It offers new experimental data on flow and initial-state geometry in different collision systems, testing theoretical models of heavy ion collisions.

Findings

Flow correlations reveal initial geometry effects.

Flow decorrelations probe longitudinal structure.

Results challenge existing theoretical models.

Abstract

The latest measurements of collective behaviour in a variety of collision systems with the ATLAS detector at the LHC, including pp collisions at 13 TeV, Xe+Xe collisions at 5.44 TeV, and Pb+Pb collisions at 5.02 TeV, are presented. They include vn-[pT] correlations, which carry important information about the initial-state geometry of the quark-gluon plasma and can shed light on any quadrupole deformation in the Xe nucleus, and measurements of flow decorrelations differential in rapidity, which probe the longitudinal structure of the colliding system. These measurements furthermore provide stringent tests of the theoretical understanding of the initial state in heavy ion collisions.