Correlations between event-by-event fluctuations of anisotropic flow harmonics are measured in Pb-Pb collisions at a center-of-mass energy per nucleon pair of 5.02 TeV, as recorded by the ALICE detector at the LHC. This study presents correlations up to the hexagonal flow harmonic, $v_6$, which was measured for the first time. The magnitudes of these higher-order correlations are found to vary as a function of collision centrality and harmonic order. These measurements are compared to viscous hydrodynamic model calculations with EKRT initial conditions and to the iEBE-VISHNU model with TRENTo initial conditions. The observed discrepancies between the data and the model calculations vary depending on the harmonic combinations. Due to the sensitivity of model parameters estimated with Bayesian analyses to these higher-order observables, the results presented in this work provide new and independent constraints on the initial conditions and transport properties in theoretical models used to describe the system created in heavy-ion collisions.
Submitted to: PRC
e-Print: arXiv:2412.15873 | PDF | inSPIRE
CERN-EP-2024-344
Figure group
Figure 1
Sensitivity of the model parameters in Bayesian analysis to the flow observables, shown as a color map. Light yellow shades represent low or no sensitivity, whereas orange and red colors represent moderate or strong sensitivities to the corresponding model parameter variation, respectively. The sensitivity analysis is based on the {T\raisebox{-.5ex}{R}ENTo}+iEBE-VISHNU model . Several key parameters are displayed, including $\eta/s(T)$, $\zeta/s(T)$, $\tau_{\rm fs}$, and $T_{\rm switch}$. More details can be found in Ref. . |  |
Figure 3
The centrality dependence of NSC($m$,$n$) in $\PbPb$ collisions at $\snn=5.02$ TeV. Results for each observable are compared with the final-state predictions from the event-by-event EKRT + viscous hydrodynamic calculations and {T\raisebox{-.5ex}{R}ENTo}+iEBE-VISHNU MAP (2022), as well as with the initial-state calculations from EKRT and {T\raisebox{-.5ex}{R}ENTo}. Panels (a) to (c) present data from Ref. . The statistical and total systematic uncertainties of the data are shown with vertical lines and boxes, respectively. The model results are shown as colored bands with the width of the band denoting the statistical uncertainties. |  |