Abstract
This paper presents measurements of charged-hadron spectra obtained in pp, p+Pb, and Pb+Pb collisions at √s or √sNN = 5.02 TeV, and in Xe+Xe collisions at √sNN = 5.44 TeV. The data recorded by the ATLAS detector at the LHC have total integrated luminosities of 25 pb−1, 28 nb−1, 0.50 nb−1, and 3 μb−1, respectively. The nuclear modification factors RpPb and RAA are obtained by comparing the spectra in heavy-ion and pp collisions in a wide range of charged-particle transverse momenta and pseudorapidity. The nuclear modification factor RpPb shows a moderate enhancement above unity with a maximum at pT≈3 GeV; the enhancement is stronger in the Pb-going direction. The nuclear modification factors in both Pb+Pb and Xe+Xe collisions feature a significant, centrality-dependent suppression. They show a similar distinct pT-dependence with a local maximum at pT≈2 GeV and a local minimum at pT≈7 GeV. This dependence is more distinguishable in more central collisions. No significant |η|-dependence is found. A comprehensive comparison with several theoretical predictions is also provided. They typically describe RAA better in central collisions and in the pT range from about 10 to 100 GeV.
Original language | English |
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Article number | 74 |
Number of pages | 58 |
Journal | Journal of High Energy Physics |
DOIs | |
Publication status | Published - 10 Jul 2023 |
Bibliographical note
39 pages, 28 figures, 3 tables, submitted to JHEP. All figures including auxiliary figures are available at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2018-17Keywords
- hep-ex
- nucl-ex