Measurement of the centrality and pseudorapidity dependence of the integrated elliptic flow in lead–lead collisions at √sNN=2.76TeV with the ATLAS detector

Abstract

The integrated elliptic flow of charged particles produced in Pb+Pb collisions at √sNN=2.76 TeV has been measured with the ATLAS detector using data collected at the Large Hadron Collider. The anisotropy parameter, v₂ , was measured in the pseudorapidity range |η|≤2.5 with the event-plane method. In order to include tracks with very low transverse momentum pT , thus reducing the uncertainty in v₂ integrated over pT , a 1 μb⎺¹ data sample recorded without a magnetic field in the tracking detectors is used. The centrality dependence of the integrated v₂ is compared to other measurements obtained with higher pT thresholds. The integrated elliptic flow is weakly decreasing with |η| . The integrated v₂ transformed to the rest frame of one of the colliding nuclei is compared to the lower-energy RHIC data.