Measurement of the azimuthal anisotropy of charged particles produced in $\sqrt{s_\mathrm{NN}} = 5.02$ TeV Pb+Pb collisions with the ATLAS detector

Understand

Measurements of the azimuthal anisotropy in lead-lead collisions at $\sqrt{s_\mathrm{NN}} = 5.02$ TeV are presented using a data sample corresponding to 0.49 $\mathrm{nb}^{-1}$ integrated luminosity collected by the ATLAS experiment at the LHC in 2015.

• The recorded minimum-bias sample is enhanced by triggers for "ultra-central" collisions, providing an opportunity to perform detailed study of flow harmonics in the regime where the initial state is dominated by fluctuations.
• The anisotropy of the charged-particle azimuthal angle distributions is characterized by the Fourier coefficients, $v_{2}-v_{7}$, which are measured using the two-particle correlation, scalar-product and event-plane methods.
• The goal of the paper is to provide measurements of the differential as well as integrated flow harmonics $v_{n}$ over wide ranges of the transverse momentum, 0.5 $<p_{\mathrm{T}}<$ 60 GeV, the pseudorapidity, $|\eta|<$ 2.5, and the collision centrality $0-80$%.