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Coherent J / ψ and ψ ′ photoproduction at midrapidity in ultra-peripheral Pb–Pb collisions at √sNN=5.02 TeV

Acharya, S ; Adolfsson, Jonatan LU ; Basu, S. LU orcid ; Christiansen, O. LU ; Matonoha, Oliver LU ; Nassirpour, Adrian LU orcid ; Ohlson, Alice LU ; Oskarsson, Anders LU ; Richert, Tuva LU and Vazquez Rueda, Omar LU , et al. (2021) In European Physical Journal C 81(8).
Abstract
The coherent photoproduction of J/ψ and ψ′ mesons was measured in ultra-peripheral Pb–Pb collisions at a center-of-mass energy sNN−−−√ = 5.02 TeV with the ALICE detector. Charmonia are detected in the central rapidity region for events where the hadronic interactions are strongly suppressed. The J/ψ is reconstructed using the dilepton (l+l−) and proton–antiproton decay channels, while for the ψ′ the dilepton and the l+l−π+π− decay channels are studied. The analysis is based on an event sample corresponding to an integrated luminosity of about 233 μb−1. The results are compared with theoretical models for coherent J/ψ and ψ′ photoproduction. The coherent cross section is found to be in a good agreement with models incorporating moderate... (More)
The coherent photoproduction of J/ψ and ψ′ mesons was measured in ultra-peripheral Pb–Pb collisions at a center-of-mass energy sNN−−−√ = 5.02 TeV with the ALICE detector. Charmonia are detected in the central rapidity region for events where the hadronic interactions are strongly suppressed. The J/ψ is reconstructed using the dilepton (l+l−) and proton–antiproton decay channels, while for the ψ′ the dilepton and the l+l−π+π− decay channels are studied. The analysis is based on an event sample corresponding to an integrated luminosity of about 233 μb−1. The results are compared with theoretical models for coherent J/ψ and ψ′ photoproduction. The coherent cross section is found to be in a good agreement with models incorporating moderate nuclear gluon shadowing of about 0.64 at a Bjorken-x of around 6×10−4, such as the EPS09 parametrization, however none of the models is able to fully describe the rapidity dependence of the coherent J/ψ cross section including ALICE measurements at forward rapidity. The ratio of ψ′ to J/ψ coherent photoproduction cross sections was also measured and found to be consistent with the one for photoproduction off protons. (Less)
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author collaboration
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
European Physical Journal C
volume
81
issue
8
article number
712
publisher
Springer
external identifiers
  • scopus:85112520844
ISSN
1434-6044
DOI
10.1140/epjc/s10052-021-09437-6
language
English
LU publication?
yes
id
92bd01ca-0601-4320-9211-2a6a2c4465a2
date added to LUP
2021-09-23 11:15:37
date last changed
2023-04-02 17:42:09
@article{92bd01ca-0601-4320-9211-2a6a2c4465a2,
  abstract     = {{The coherent photoproduction of J/ψ and ψ′ mesons was measured in ultra-peripheral Pb–Pb collisions at a center-of-mass energy sNN−−−√ = 5.02 TeV  with the ALICE detector. Charmonia are detected in the central rapidity region for events where the hadronic interactions are strongly suppressed. The J/ψ is reconstructed using the dilepton (l+l−) and proton–antiproton decay channels, while for the ψ′  the dilepton and the l+l−π+π− decay channels are studied. The analysis is based on an event sample corresponding to an integrated luminosity of about 233 μb−1. The results are compared with theoretical models for coherent J/ψ and ψ′ photoproduction. The coherent cross section is found to be in a good agreement with models incorporating moderate nuclear gluon shadowing of about 0.64 at a Bjorken-x of around 6×10−4, such as the EPS09 parametrization, however none of the models is able to fully describe the rapidity dependence of the coherent J/ψ cross section including ALICE measurements at forward rapidity. The ratio of ψ′ to J/ψ coherent photoproduction cross sections was also measured and found to be consistent with the one for photoproduction off protons.}},
  author       = {{Acharya, S and Adolfsson, Jonatan and Basu, S. and Christiansen, O. and Matonoha, Oliver and Nassirpour, Adrian and Ohlson, Alice and Oskarsson, Anders and Richert, Tuva and Vazquez Rueda, Omar and Silvermyr, David and Zurlo, N}},
  issn         = {{1434-6044}},
  language     = {{eng}},
  number       = {{8}},
  publisher    = {{Springer}},
  series       = {{European Physical Journal C}},
  title        = {{Coherent J / ψ and ψ ′ photoproduction at midrapidity in ultra-peripheral Pb–Pb collisions at √sNN=5.02 TeV}},
  url          = {{http://dx.doi.org/10.1140/epjc/s10052-021-09437-6}},
  doi          = {{10.1140/epjc/s10052-021-09437-6}},
  volume       = {{81}},
  year         = {{2021}},
}