Event-by-Event Flow Harmonic Analysis of Xe–Xe Collisions and Comparison with Pb–Pb Collisions at the LHC

This talk presents measurements of the event-by-event distributions of harmonic flow coefficients (vₙ, with n = 2, 3, 4) in xenon–xenon (Xe–Xe) collisions at 5.44 TeV, using data collected by the ATLAS detector at the Large Hadron Collider. Charged particle tracks with transverse momentum pT > 0.5 GeV and pseudorapidity range |η| < 2.5 were analyzed. The distributions of vₙ were unfolded to account for finite multiplicity effects and detector resolution, employing Bayesian unfolding methods. The unfolded Xe–Xe flow harmonic distributions are systematically compared to corresponding Pb–Pb measurements. This comparison reveals notable similarities and differences in both shape and magnitude of the flow harmonic distributions between the two collision systems. These results provide valuable insights into the initial-state geometry fluctuations, the hydrodynamic behavior of the quark-gluon plasma produced in heavy-ion collisions, and the dependence of flow dynamics on the system size and collision geometry.