Measurements of collective behavior in pp, Xe+Xe, and Pb+Pb collisions with the ATLAS detector

ATLAS measurements of collective, flow phenomena in a variety of collision systems, including $pp$ collisions at 13 TeV, Xe+Xe collisions at 5.44 TeV, and Pb+Pb collisions at 5.02 TeV are presented. A measurement of the sensitivity of two-particle correlations in $pp$ collisions to the presence of jets is presented. By rejecting particles associated with low-$\pT$ jets, this data can distinguish the role that semi-hard processes play in the collective phenomena observed in $pp$ collisions (details in ATLAS-CONF-2020-018). The correlation between the event-wise average transverse momentum ($[\pT]$) and the harmonic flow ($v_{n}$) carries important information about the initial-state geometry of the Quark-Gluon Plasma. Additionally, the potential quadrupole deformation in Xe+Xe is predicted to produce an initial state with enhanced shape and size fluctuations, and result in non-trivial change in the correlation. A new measurement of $v_{n}-[\pT]$ correlations in Xe+Xe and Pb+Pb collisions is discussed for harmonics $n=2$, 3, and 4 (ATLAS-CONF-2021-001).