Measurement of the Azimuthal Anisotropy of Charged Particle Production in Xe+Xe Collisions at 5.44 TeV with the ATLAS Detector

ATLAS measurements of flow harmonics ($v_{n}$) and their fluctuations in Pb+Pb and Xe+Xe collisions covering a wide range of transverse momenta, pseudorapidity and collision centrality are presented. The $v_{n}$ are measured up to $n=7$ using the two-particle correlations, multi-particle cumulants and scalar product methods. The measurements are also performed using non-flow subtraction techniques -- recently developed for measurements in proton-nucleus and proton-proton collisions -- to improve the understanding of flow in peripheral Pb+Pb and Xe+Xe collisions. The effects of geometric fluctuations and of viscous effects, both of which are stronger in the smaller Xe+Xe system are demonstrated. A universal scaling in the transverse-momentum dependence of the $v_{n}$ is observed for both systems.