Measurement of the correlation between flow harmonics of different order in lead–lead collisions at [formula omitted] with ATLAS

Abstract

Measurement of the correlation between elliptic or triangular flow coefficients vm (m = 2, 3) and other flow harmonics vn (n = 2 to 5) in sNN=2.76 TeV Pb+Pb collisions using the data collected by the ATLAS experiment at the LHC is presented. The correlations are measured for the different centrality intervals. Each centrality interval is sub divided into event shape classes defined using the ellipticity or triangularity measured in the forward detectors, and for each of the event shape classes the vm−vn correlations are measured in the midrapidity region. The v2 and v3 values show anticorrelation with each other while positive correlations are observed between v2−v4,v2−v5 and v3−v5. The vm−vn correlations (for n = 4, 5) are not reproduced by the ϵm−ϵn correlations predicted by initial geometry models, but are found to be well described by a two component model with a linear response contribution and a nonlinear response contribution which is proportional to v22 in the case of v4 and to v2v3 in the case of v5. The linear and nonlinear contributions are extracted from the measured correlations and compared with results from previous event-plane correlation measurements.