Anisotropic flow in Xe-Xe collisions at root s(NN)=5.44 TeV

The first measurements of anisotropic flow coefficients v n for mid-rapidity charged particles in Xe–Xe collisions at s NN =5.44 TeV are presented. Comparing these measurements to those from Pb–Pb collisions at s NN =5.02 TeV, v 2 is found to be suppressed for mid-central collisions at the same centrality, and enhanced for central collisions. The values of v 3 are generally larger in Xe–Xe than in Pb–Pb at a given centrality. These observations are consistent with expectations from hydrodynamic predictions. When both v 2 and v 3 are divided by their corresponding eccentricities for a variety of initial state models, they generally scale with transverse density when comparing Xe–Xe and Pb–Pb, with some deviations observed in central Xe–Xe and Pb–Pb collisions. These results assist in placing strong constraints on both the initial state geometry and medium response for relativistic heavy-ion collisions.