Non-Gaussian Elliptic-flow Fluctuations in PbPb Collisions at ?sNN=5.02 TeV

Event-by-event fluctuations in the elliptic-flow coefficient v2are studied in PbPb collisions at ?sNN=5.02TeVusing the CMS detector at the CERN LHC. Elliptic-flow probability distributions p(v2)for charged particles with transverse momentum 0.3 <pT<3.0GeV/cand pseudorapidity |?| <1.0are determined for different collision centrality classes. The moments of the p(v2)distributions are used to calculate the v2coefficients based on cumulant orders 2, 4, 6, and 8. A rank ordering of the higher-order cumulant results and nonzero standardized skewness values obtained for the p(v2)distributions indicate non-Gaussian initial-state fluctuations. Bessel–Gaussian and elliptic power fits to the flow distributions are studied to characterize the initial-state spatial anisotropy