Multiparticle azimuthal correlations in p -Pb and Pb-Pb collisions at the CERN Large Hadron Collider
Abelev, Betty; Adam, Jaroslav; Adamová, Dagmar; Aggarwal, Madan M.; Aglieri Rinella, Gianluca; Agnello, Michelangelo; Agostinelli, Andrea; Agrawal, Nikita; Ahammed, Zubayer; Ahmad, Nazeer; Alme, Johan; Erdal, Hege Austrheim; Helstrup, Håvard; Hetland, Kristin Fanebust; Kileng, Bjarte; Altinpinar, Sedat; Djuvsland, Øystein; Fehlker, Dominik; Haaland, Øystein Senneset; Huang, Meidana; Lønne, Per-Ivar; Nystrand, Joakim; Rehman, Attiq ur; Røhrich, Dieter; Skjerdal, Kyrre; Ullaland, Kjetil; Velure, Arild; Wagner, Boris; Yang, Shiming; Zhou, Zhuo; Arsene, Ionut Christian; Bätzing, Paul Christoph; Dordic, Olja; Lindal, Svein; Mahmood, Sohail Musa; Milosevic, Jovan; Qvigstad, Henrik; Richter, Matthias Rudolph; Røed, Ketil; Skaali, Toralf Bernhard; Tveter, Trine Spedstad; Wikne, Jon Christopher; Zhao, Chengxin; Langøy, Rune; Lien, Jørgen André; Ahn, Sang Un; Ahn, Sul-Ah; Aiola, Salvatore; Ajaz, Muhammad; Akindinov, Alexander; ALICE, Collaboration
Peer reviewed, Journal article
Published version
Permanent lenke
https://hdl.handle.net/1956/9851Utgivelsesdato
2014-11-03Metadata
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Originalversjon
https://doi.org/10.1103/physrevc.90.054901Sammendrag
Measurements of multiparticle azimuthal correlations (cumulants) for charged particles in p-Pb at √sNN=5.02 TeV and Pb-Pb at √sNN=2.76 TeV collisions are presented. They help address the question of whether there is evidence for global, flowlike, azimuthal correlations in the p-Pb system. Comparisons are made to measurements from the larger Pb-Pb system, where such evidence is established. In particular, the second harmonic two-particle cumulants are found to decrease with multiplicity, characteristic of a dominance of few-particle correlations in p-Pb collisions. However, when a |Δη| gap is placed to suppress such correlations, the two-particle cumulants begin to rise at high multiplicity, indicating the presence of global azimuthal correlations. The Pb-Pb values are higher than the p-Pb values at similar multiplicities. In both systems, the second harmonic four-particle cumulants exhibit a transition from positive to negative values when the multiplicity increases. The negative values allow for a measurement of v2{4} to be made, which is found to be higher in Pb-Pb collisions at similar multiplicities. The second harmonic six-particle cumulants are also found to be higher in Pb-Pb collisions. In Pb-Pb collisions, we generally find v2{4}≃v2{6}≠0 which is indicative of a Bessel-Gaussian function for the v2 distribution. For very high-multiplicity Pb-Pb collisions, we observe that the four- and six-particle cumulants become consistent with 0. Finally, third harmonic two-particle cumulants in p-Pb and Pb-Pb are measured. These are found to be similar for overlapping multiplicities, when a |Δη|>1.4 gap is placed.