Author(s) |
Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Abdulsalam, A.; Choudhury, R. K.; Dutta, D.; Kailas, S.; Kumar, V.; Mohanty, A. K.; Pant, L. M.; Shukla, P.; and others (NPD)
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The azimuthal anisotropy of charged particles in Pb-Pb collisions at √sNN = 2:76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pT) range up to approximately 60 GeV/c. The data cover both the low-pT region associated with hydrodynamic flow phenomena and the high-pT region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (v2) of the particles is extracted by correlating charged tracks with respect to the event-plane reconstructed by using the energy deposited in forward-angle calorimeters. For the six bins of collision centrality studied, spanning the range of 0–60% most-central events, the observed v2 values are found to first increase with pT, reaching a maximum around pT = 3 GeV/c, and then to gradually decrease to almost zero, with the decline persisting up to at least pT = 40 GeV/c over the full centrality range measured. |