Latest ALICE results on J/$\ddot{I}ˆ$ photoproduction in ultra-peripheral collisions at the LHC

Abstract

Ultra-peripheral collisions (UPCs), studied using the ALICE detector, allow us to investigate the low-$x$ behavior of the gluon distribution of the colliding particles. Two new measurements of coherent J/$\ddot{I}ˆ$ photoproduction cross section from Pb-Pb UPCs at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV are presented: the first measurement of the $|t|$-dependence of the cross section providing a new tool to investigate the transverse gluonic structure at low Bjorken-$x$ and a rapidity-differential measurement at midrapidity allowing us to provide stringent constraints on nuclear gluon shadowing and saturation models. In addition, prospects for heavy vector meson photoproduction measurements in LHC Run 3 and 4 are presented.

Submission to SciPost, Proceedings of DIS 2021 conference, 12-16 April 2021