Naslov
Multiparticle azimuthal correlations in p-Pb and Pb-Pb collisions at the CERN Large Hadron Collider

Autori
Abelev, B. ... ; Antičić, Tome ; Gotovac, Sven ; Mudnić, Eugen ; Planinić, Mirko ; Poljak, Nikola ; Simatović, Goran ; Šuša, Tatjana ; Vicković, Linda ; ...

Izvornik
Physical Review C (0556-2813) 90 (2014), 5; 054901-1

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
LHC; ALICE; pp; PbPb; Azimuthal correlations

Sažetak
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.

Izvorni jezik
Engleski

Znanstvena područja
Fizika

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