Probing the spatial distribution of gluons within the proton in the coherent vector meson production at large $|t|$

Abstract

The coherent production of vector mesons in photon - hadron interactions is considered one of the most promising observables to probe the QCD dynamics at high energies and the transverse spatial distribution of the gluons in the hadron wave function. In this paper, we perform an exploratory study about the dependence of the transverse momentum distributions, $dσ/dt$, on the model assumed for the proton density profile. We consider a set of non-Gaussian profiles and include them in the forward dipole - proton scattering amplitude associated with the IP-sat model. We demonstrate that the predictions for $dσ/dt$ are similar in the HERA kinematical range, but are very distinct for values of $t$ that will be probed in future colliders. In particular, the presence of diffractive dips in the $t$-distributions associated with the production of $J/Ψ$ and $ρ$ mesons is strongly dependent on the model assumed for the density profile. Similar conclusions are also derived when the non-linear effects on the dipole - target interaction are disregarded. Our results indicate that a future study of the coherent vector meson production at large - $t$ will be useful to constrain the spatial distribution of gluons within the proton.