Photoproduction of $J/\psi$ with neutron tagging in ultra-peripheral collisions of nuclei at RHIC and the LHC

2023-03-21 2023-08-14

We present predictions for the cross sections of the coherent and incoherent $J/\psi$ photoproduction in ultra-peripheral collisions at RHIC and at the LHC calculated for different classes of events depending on the presence of neutrons emitted by colliding nuclei. Since strong nucleus-nucleus interactions in UPCs are suppressed, it is usually assumed that neutrons at forward rapidities originate mainly from the electromagnetic dissociation of colliding nuclei caused by additional photon exchanges. This is a reasonable assumption for the coherent photoproduction where the state of the target nucleus remains intact. We consider additional sources of neutrons in the incoherent quasielastic and nucleon dissociative $J/\psi$ photoproduction and show that these processes significantly change probabilities of neutron emission compared to calculations when only neutrons from electromagnetic dissociation of nuclei are considered. Such studies should allow one to explore the dynamics of nuclear shadowing in the incoherent $J/\psi$ photoproduction down to $x \sim 10^{-5}$.
Comment: 20 pages, 9 figures, new version accepted by PRC

High Energy Physics - Phenomenology; High Energy Physics - Experiment; Nuclear Experiment; text

COO oai:arXiv.org:2303.12052
1381533479

CORNELL UNIV
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