Measurement of flow harmonics with multi-particle cumulants in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV with the ATLAS detector

ATLAS measurements of the azimuthal anisotropy in lead-lead collisions at $\sqrt{s_{\mathrm{NN}}}=2.76$ TeV are shown using a dataset of approximately 7 $\mu$b$^{-1}$ collected in 2010. The measurements are performed for charged particles with transverse momenta $0.5<p_{\mathrm{T}}<20$~GeV and in the pseudorapidity range $|\eta|<2.5$. The anisotropy is characterized by the Fourier coefficients, $\mathrm{v}_n$, of the charged particle azimuthal angle distribution for $n=2-4$. The Fourier coefficients have been evaluated using multi-particle cumulants calculated with the generating function method. Results on the transverse momentum, pseudorapidity and centrality dependence of the $\mathrm{v}_n$ coefficients are presented. The elliptic flow ($\mathrm{v}_2$) is obtained from the two-, four-, six- and eight-particle cumulants while higher-order coefficients, $\mathrm{v}_3$ and $\mathrm{v}_4$ are determined with two- and four-particle cumulants. Flow harmonics $\mathrm{v}_n$ measured with four-particle cumulants are significantly reduced compared to the measurement involving two-particle cumulants. A comparison to $\mathrm{v}_n$ measurements obtained using different analysis methods and previously reported from the LHC experiments is also shown. Results of measurements of flow fluctuations evaluated with multi-particle cumulants are shown as a function of transverse momentum and the collision centrality.