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.File | Dimensione | Formato | |
---|---|---|---|
PhysRevLett.109.022301.pdf
Accesso aperto
Tipo di file:
PDF EDITORIALE
Dimensione
333.68 kB
Formato
Adobe PDF
|
333.68 kB | Adobe PDF | Visualizza/Apri |
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.