Measurement of the Centrality and Pseudorapidity Dependence of the Integrated Elliptic Flow in Lead−Lead Collisions at \sqrt{^sNN} = 2.76 TeV with the ATLAS Detector


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 p_T, 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 p_T 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.



Elliptic flow, Proton-proton interactions, Anisotropy, Transverse momentum


CC BY 4.0 (Attribution), ©2014 CERN for the ATLAS Collaboration