Measurement of vn coefficients and Reaction-Plane Correlations in ATLAS

Hadron correlations are important tools used to study the properties of the medium produced in relativistic heavy ion collisions. We present detailed measurements of flow harmonics v2 -v6 via di-hadron correlations in broad pT, Deltaeta and centrality ranges using the 2010 Pb+Pb data from ATLAS. These measurements are compared to the corre sponding values obtained via event-plane measurements. This result provides new insights on the origin of the long range ”ridge” structure over broad pT ranges. Measurements of the dipolar flow (v1 ) associated with initial dipole asymmetry as function of pT and centrality are also presented. Finally, the results of correlations between harmonic planes of different orders measured via two-plane and three-plane correlations are also discussed.