Abstract
Two-particle long-range azimuthal correlations are measured in photonuclear collisions using 1.7 nb-1 of 5.02 TeV Pb+Pb collision data collected by the ATLAS experiment at the LHC. Candidate events are selected using a dedicated high-multiplicity photonuclear event trigger, a combination of information from the zero-degree calorimeters and forward calorimeters, and from pseudorapidity gaps constructed using calorimeter energy clusters and charged-particle tracks. Distributions of event properties are compared between data and Monte Carlo simulations of photonuclear processes. Two-particle correlation functions are formed using charged-particle tracks in the selected events, and a template-fitting method is employed to subtract the non-flow contribution to the correlation. Significant nonzero values of the second- and third-order flow coefficients are observed and presented as a function of charged-particle multiplicity and transverse momentum. The results are compared with flow coefficients obtained in proton-proton and proton-lead collisions in similar multiplicity ranges, and with theoretical expectations. The unique initial conditions present in this measurement provide a new way to probe the origin of the collective signatures previously observed only in hadronic collisions.
Original language | English |
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Article number | 014903 |
Number of pages | 31 |
Journal | Physical Review C |
Volume | 104 |
Issue number | 1 |
DOIs | |
Publication status | Published - 12 Jul 2021 |
Bibliographical note
47 pages in total, author list starting page 32, 18 figures, 1 table, submitted to Phys. Rev. C. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2018-27/
Keywords
- hep-ex
- nucl-ex