Azimuthal anisotropy of jet particles in p-Pb and Pb-Pb collisions at √sNN=5.02 TeV


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Acharya S., Adamová D., Adler A., Aglieri Rinella G., Agnello M., Agrawal N., ...More

JOURNAL OF HIGH ENERGY PHYSICS, vol.2024, no.8, 2024 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 2024 Issue: 8
  • Publication Date: 2024
  • Doi Number: 10.1007/jhep08(2024)234
  • Journal Name: JOURNAL OF HIGH ENERGY PHYSICS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Heavy Ion Experiments, Jets, Particle Correlations and Fluctuations
  • Open Archive Collection: AVESIS Open Access Collection
  • Yıldız Technical University Affiliated: Yes

Abstract

The azimuthal anisotropy of particles associated with jets (jet particles) at midrapidity is measured for the first time in p-Pb and Pb-Pb collisions at root sNN = 5.02 TeV down to transverse momentum (p(T)) of 0.5 GeV/c and 2 GeV/c, respectively, with ALICE. The results obtained in p-Pb collisions are based on a novel three-particle correlation technique. The azimuthal anisotropy coefficient v(2) in high-multiplicity p-Pb collisions is positive, with a significance reaching 6.8 sigma at low p(T), and its magnitude is smaller than in semicentral Pb-Pb collisions. In contrast to the measurements in Pb-Pb collisions, the v(2) coefficient is also found independent of p(T) within uncertainties. Comparisons with the inclusive charged-particle v(2) and with AMPT calculations are discussed. The predictions suggest that parton interactions play an important role in generating a non-zero jet-particle v(2) in p-Pb collisions, even though they overestimate the reported measurement. These observations shed new insights on the understanding of the origin of the collective behaviour of jet particles in small systems such as p-Pb collisions, and provide significant stringent new constraints to models.