Photoproduction of low-pT J/ψ from peripheral to central Pb−Pb collisions at 5.02 TeV

  • An excess of J/ψ yield at very low transverse momentum (pT<0.3 GeV/c), originating from coherent photoproduction, is observed in peripheral and semicentral hadronic Pb−Pb collisions at a center-of-mass energy per nucleon pair of √sNN=5.02 TeV. The measurement is performed with the ALICE detector via the dimuon decay channel at forward rapidity (2.5<y<4). The nuclear modification factor at very low pT and the coherent photoproduction cross section are measured as a function of centrality down to the 10% most central collisions. These results extend the previous study at √sNN=2.76 TeV, confirming the clear excess over hadronic production in the pT range 0−0.3 GeV/c and the centrality range 70−90%, and establishing an excess with a significance greater than 5σ also in the 50−70% and 30−50% centrality ranges. The results are compared with earlier measurements at √sNN=2.76 TeV and with different theoretical predictions aiming at describing how coherent photoproduction occurs in hadronic interactions with nuclear overlap.

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ArXiv Id:
Parent Title (English):arXiv
Series (Serial Number):CERN Report (CERN-EP-2022-071)
Document Type:Preprint
Date of Publication (online):2022/04/22
Date of first Publication:2022/04/22
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Creating Corporation:ALICE (Körperschaft)
Release Date:2023/11/30
Issue:2204.10684 Version 1
Edition:Version 1
Page Number:15
Institutes:Physik / Physik
Informatik und Mathematik / Informatik
Wissenschaftliche Zentren und koordinierte Programme / Frankfurt Institute for Advanced Studies (FIAS)
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 53 Physik / 530 Physik
Licence (German):License LogoCreative Commons - Namensnennung 4.0