Exclusive $ρ$ and $J/Ψ$ photoproduction in ultraperipheral $pA$ collisions: Predictions of the gluon saturation models for the momentum transfer distributions

V. Gonçalves; F. Navarra; D. Spiering

Paper

Exclusive $ρ$ and $J/Ψ$ photoproduction in ultraperipheral $pA$ collisions: Predictions of the gluon saturation models for the momentum transfer distributions

Abstract

In this letter we complement previous studies on exclusive vector meson photoproduction in hadronic collisions presenting a comprehensive analysis of the

- spectrum measured in exclusive

and

photoproduction in

collisions at the LHC. We compute the differential cross sections considering two phenomenological models for the gluon saturation effects and present predictions for

and

collisions. Moreover, we compare our predictions with the recent preliminary CMS data for the exclusive

photoproduction. We demonstrate that the gluon saturation models are able to describe the CMS data at small -

. On the other hand, the models underestimate the few data point at large --

. Our results indicate that future measurements of the large --

region can be useful to probe the presence or absence of a dip in the

-- spectrum and discriminate between the different approaches to the gluon saturation effects.