Measurement of long-range pseudorapidity correlations and azimuthal harmonics in √s_NN=5.02 TeV proton-lead collisions with the ATLAS detector

Agustoni, Marco; Beck, Hans Peter; Cervelli, Alberto; Ereditato, Antonio; Haug, Sigve; Marti, Lukas; Meloni, Federico; Schneider, Basil; Sciacca, Gianfranco; Stramaglia, Maria; Stucci, Stefania Antonia; Weber, Michael (2014). Measurement of long-range pseudorapidity correlations and azimuthal harmonics in √s_NN=5.02 TeV proton-lead collisions with the ATLAS detector. Physical review. C - nuclear physics, C90(4), 044906. American Institute of Physics 10.1103/PhysRevC.90.044906

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Measurements of two-particle correlation functions and the first five azimuthal harmonics, v 1 to v 5 , are presented, using 28 nb −1 of p+Pb collisions at a nucleon-nucleon center-of-mass energy of √s NN=5.02 TeV measured with the ATLAS detector at the LHC. Significant long-range “ridgelike” correlations are observed for pairs with small relative azimuthal angle (|Δϕ|<π/3 ) and back-to-back pairs (|Δϕ|>2π/3 ) over the transverse momentum range 0.4<p T <12 GeV and in different intervals of event activity. The event activity is defined by either the number of reconstructed tracks or the total transverse energy on the Pb-fragmentation side. The azimuthal structure of such long-range correlations is Fourier decomposed to obtain the harmonics v n as a function of p T and event activity. The extracted v n values for n=2 to 5 decrease with n . The v 2 and v 3 values are found to be positive in the measured p T range. The v 1 is also measured as a function of p T and is observed to change sign around p T ≈1.5 –2.0 GeV and then increase to about 0.1 for p T >4 GeV. The v 2 (p T ) , v 3 (p T ) , and v 4 (p T ) are compared to the v n coefficients in Pb+Pb collisions at √s NN=2.76 TeV with similar event multiplicities. Reasonable agreement is observed after accounting for the difference in the average p T of particles produced in the two collision systems.

Item Type:

Journal Article (Original Article)


10 Strategic Research Centers > Albert Einstein Center for Fundamental Physics (AEC)
08 Faculty of Science > Physics Institute > Laboratory for High Energy Physics (LHEP)

UniBE Contributor:

Agustoni, Marco, Beck, Hans Peter, Cervelli, Alberto, Ereditato, Antonio, Haug, Sigve, Marti, Lukas, Meloni, Federico, Schneider, Basil, Sciacca, Gianfranco, Stramaglia, Maria Elena, Stucci, Stefania, Weber, Michele


500 Science > 530 Physics




American Institute of Physics




Jan Dirk Brinksma

Date Deposited:

10 Jun 2015 15:28

Last Modified:

02 Mar 2023 23:26

Publisher DOI:


Additional Information:

Kollaboration - Es sind nur die Berner Autoren namentlich erwähnt.




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