Flow harmonics in Pb+Pb collisions at energy of $\sqrt{s_{NN}}$ = 2.76 TeV with the ATLAS detector

We report on measurements of the anisotropy of charged particles in lead-lead collisions at $\sqrt{s_{NN}}$ = 2.76 TeV, using multi-particle cumulants calculated with the generating function method. The results on the transverse momentum, pseudorapidity and centrality dependence of the elliptic flow ($v_{2}$) obtained from two-, four-, six- and eight-particle cumulants are presented. Higher-order coefficients, $v_{3}$ and $v_{4}$ are also derived using two- and four-particle cumulants and shown as a function of centrality and transverse momentum. A reduction of contributions not related to the initial geometry for $v_{n}$ studied with cumulant expansion of correlations between more than two particles is discussed. Event-by-event fluctuations of the flow harmonics evaluated with multi-particle cumulants as a function of transverse momentum and the collision centrality are also presented. These results are complemented with the $p_{T}$-integrated elliptic flow measured in the pseudorapidity range |$\eta$|< 2.5 with the event plane method, exploring the range of very low transverse momenta. This was achieved by applying dedicated track reconstruction methods. The centrality dependence of the integrated $v_{2}$, spanning the range of 0–80% of most central Pb+Pb collisions, is compared to other measurements obtained with higher $p_{T}$ thresholds. The pseudorapidity dependence of the integrated elliptic flow in different centrality intervals is discussed and compared to the lower energy RHIC data.