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  • Coherent [Formula omitted] ...
    Acharya, S; Adamová, D; Adler, A; Adolfsson, J; Rinella, G. Aglieri; Agnello, M; Agrawal, N

    The European physical journal. C, Particles and fields, 08/2021, Letnik: 81, Številka: 8
    Journal Article

    The coherent photoproduction of Formula omitted and Formula omitted mesons was measured in ultra-peripheral Pb-Pb collisions at a center-of-mass energy Formula omitted TeV with the ALICE detector. Charmonia are detected in the central rapidity region for events where the hadronic interactions are strongly suppressed. The Formula omitted is reconstructed using the dilepton ( Formula omitted) and proton-antiproton decay channels, while for the Formula omitted the dilepton and the Formula omitted decay channels are studied. The analysis is based on an event sample corresponding to an integrated luminosity of about 233 Formula omitted. The results are compared with theoretical models for coherent Formula omitted and Formula omitted 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 Formula omitted, such as the EPS09 parametrization, however none of the models is able to fully describe the rapidity dependence of the coherent Formula omitted cross section including ALICE measurements at forward rapidity. The ratio of Formula omitted to Formula omitted coherent photoproduction cross sections was also measured and found to be consistent with the one for photoproduction off protons.