Exclusive vector meson photoproduction at the LHC and a future circular collider: A closer look on the final state

Over the past years, the LHC experiments have reported experimental evidence for processes associated to photon-photon and photon-hadron interactions, showing their potential to investigate the production of low- and high-mass systems in exclusive events. In the particular case of the photoproduction of vector mesons, the experimental study of this final state is expected to shed light on the description of the QCD dynamics at small values of the Bjorken-$x$ variable. In this paper, we extend previous studies for the exclusive $J/\mathrm{\Psi }$ and $\mathrm{\Upsilon }$ photoproduction in $pp$ collisions based on the nonlinear QCD dynamics by performing a detailed study of the final-state distributions that can be measured experimentally at the LHC and at a future circular collider. Predictions for the rapidity and transverse momentum distributions of the vector mesons and of final-state dimuons are presented for $pp$ collisions at $\sqrt{s}=7$, 13, and 100 TeV.

Figure 1

Rapidity distribution for the exclusive $J/\mathrm{\Psi }$ photoproduction in $pp$ collisions at $\sqrt{s}=13$ (left panel) and 100 TeV (right panel) considering different models for the survival probability. The prediction derived disregarding the extra soft reinteractions between the incident protons is represented by the solid line.

Figure 2

Predictions for the energy dependence of the total cross sections for the photoproduction of $J/\psi$ (left panel) and $\mathrm{\Upsilon }$ (right panel) in $pp$ collisions considering the default values of the SuperCHIC2 and those associated to the bCGC model. For comparison, we also present the predictions for $\mathrm{\Upsilon }$ production obtained with the fitting parameters originally extracted from the HERA data.

Figure 3

Rapidity (upper panels) and transverse momentum (lower panels) distributions at LHC and FCC energy regimes for the $J/\mathrm{\Psi }$ (left) and $\mathrm{\Upsilon }$ (right) photoproduction.

Figure 4

Final-state distributions of the dimuons from the decay of the $J/\mathrm{\Psi }$ (left panels) and $\mathrm{\Upsilon }(1\mathrm{S})$ (right panels) in $pp$ collision at $\sqrt{s}=13\mathrm{TeV}$.

Figure 5

Final-state distributions of the dimuons from the decay of the $J/\mathrm{\Psi }$ (left panels) and $\mathrm{\Upsilon }(1\mathrm{S})$ (right panels) in $pp$ collision at $\sqrt{s}=100\mathrm{TeV}$.