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 0.65 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.
Eser Adı (dc.title) | Coherent J/ψ and ψ′ photoproduction at midrapidity in ultra-peripheral Pb–Pb collisions at √sNN = 5.02 TeV |
Yayın Türü (dc.type) | Diğer |
Yazar/lar (dc.contributor.author) | KARASU UYSAL, Ayben |
Yazar/lar (dc.contributor.author) | ALICE Collaboration |
Atıf Dizini (dc.source.database) | Wos |
Atıf Dizini (dc.source.database) | Scopus |
Yayın Tarihi (dc.date.issued) | 2021 |
Kayıt Giriş Tarihi (dc.date.accessioned) | 2022-03-05T13:25:32Z |
Açık Erişim tarihi (dc.date.available) | 2022-03-05T13:25:32Z |
Özet (dc.description.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 0.65 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. |
Tek Biçim Adres (dc.identifier.uri) | http://hdl.handle.net/20.500.12498/5383 |