$\langle \cos 4[\Psi_2(p_T^a)-\Psi_2(p_T^t)]\rangle$ with $|\Delta\eta| > 0.8$ and $0.2 < \textit{p}_T^t < 0.6$ GeV/c at $\sqrt{s_{NN}} = 5.02$ TeV. The errors bars correspond to statistical uncertainties while the shaded color bands correspond to systematic uncertainties.
Keywords: Flow, Flow vector fluctuations, pT-dependent flow vector fluctuations, Pb-Pb collisions, 5.02 TeV
$\langle \cos 4[\Psi_2(p_T^a)-\Psi_2(p_T^t)]\rangle$ is a direct probe of flow angle fluctuations. The observable is obtained from the ratio of four-particle correlations.
Data sample: LHC15o
Events cuts: kInt7 trigger, |Vz| < 10cm, V0M centrality estimator, Pileup cut
Track cuts: Filterbit 96, No. of TPC cluster > 70, NUA weights, Reference pT [0.2,5.0], |eta| < 0.8