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

Abstract

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 $\sqrt{s_{\mathrm{NN}}}$ = 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.

Replaced with the published version. Added the journal reference and the DOI. All the figures and tables can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/HIN-21-010 (CMS Public Pages)

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• Glauber Modeling in High Energy Nuclear Collisions
• Description and performance of track and primary-vertex reconstruction with the CMS tracker
• Elliptic flow in the Gaussian model of eccentricity fluctuations
• Skewness of elliptic flow fluctuations
• Eccentricity distributions in nucleus-nucleus collisions
• Azimuthal Anisotropy Distributions in High-Energy Collisions
• Statistical uncertainties of the $v_n\{2k\}$ harmonics from Q-cumulants

Cited by in corpus (3)

• Impact parameter dependence of anisotropic flow: Bayesian reconstruction in ultracentral nucleus-nucleus collisions
• Bayesian reconstruction of anisotropic flow fluctuations at fixed impact parameter
• A Novel Approach to Fast Calculation of High-Order Q-Cumulants