Higher-order moments of the elliptic flow distribution in PbPb collisions at $\sqrt{s_{\mathrm{N}\mathrm{N}}}$ = 5.02 TeV

The hydrodynamic flow-like behavior of charged hadrons in high-energy lead-lead collisions is studied through multiparticle correlations. The elliptic anisotropy values based on different orders of multiparticle cumulants, $v_2\{2k\}$, are measured up to the tenth order ($k$ = 5) as functions of the collision centrality at a nucleon-nucleon center-of-mass energy of $\sqrt{s_{\mathrm{N}\mathrm{N}}}$ = 5.02 TeV. The data were recorded by the CMS experiment at the LHC and correspond to an integrated luminosity of 0.607 nb${}^{-1}$. A hierarchy is observed between the coefficients, with $v_2\{2\}>v_2\{4\}\gtrsim v_2\{6\}\gtrsim v_2\{8\}\gtrsim v_2\{10\}$. Based on these results, centrality-dependent moments for the fluctuation-driven event-by-event $v_2$ distribution are determined, including the skewness, kurtosis and, for the first time, superskewness. Assuming a hydrodynamic expansion of the produced medium, these moments directly probe the initial-state geometry in high-energy nucleus-nucleus collisions.