The azimuthal anisotropy of charged particles in Pb-Pb collisions at root S-NN = 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (p(T)) range up to approximately 60 GeV/c. The data cover both the low-p(T) region associated with hydrodynamic flow phenomena and the high-p(T) region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (nu(2)) 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 nu(2) values are found to first increase with p(T), reaching a maximum around p(T) = 3 GeV/c, and then to gradually decrease to almost zero, with the decline persisting up to at least p(T) = 40 GeV/c over the full centrality range measured.

Azimuthal Anisotropy of Charged Particles at High Transverse Momenta in Pb-Pb Collisions at root S-NN=2.76 TeV

AMAPANE, Nicola Carlo;ARGIRO', Stefano;BOTTA, CRISTINA;CASTELLO, Roberto;COSTA, Marco;MIGLIORE, Ernesto;MONACO, Vincenzo;MUSICH, MARCO;OBERTINO, Maria Margherita;PELLICCIONI, Mario;POTENZA, ALBERTO;ROMERO, Alessandra;SACCHI, Roberto;SOLA, VALENTINA;SOLANO, Ada Maria;CERMINARA, GIANLUCA;BELLAN, Riccardo;COVARELLI, Roberto;
2012-01-01

Abstract

The azimuthal anisotropy of charged particles in Pb-Pb collisions at root S-NN = 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (p(T)) range up to approximately 60 GeV/c. The data cover both the low-p(T) region associated with hydrodynamic flow phenomena and the high-p(T) region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (nu(2)) 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 nu(2) values are found to first increase with p(T), reaching a maximum around p(T) = 3 GeV/c, and then to gradually decrease to almost zero, with the decline persisting up to at least p(T) = 40 GeV/c over the full centrality range measured.
2012
109
022301
022315
S. Chatrchyan;V. Khachatryan;A. M. Sirunyan;A. Tumasyan;W. Adam;T. Bergauer;M. Dragicevic;J. Ero;C. Fabjan;M. Friedl;R. Fruhwirth;V. M. Gh...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2318/118314
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