Speaker
Description
Ultra-peripheral collisions (UPCs) at the LHC, studied using the ALICE detector, allow us to investigate, using photon-induced interactions, processes sensitive to the low x behaviour of the gluon distribution of the colliding particles and provide important constraints on the initial stages of the collision.
The first measurement of the t-dependence of the coherent $\rm{J/\psi}$ photonuclear cross section is presented. The cross section is obtained at midrapidity from Pb–Pb UPCs at $\sqrt{s_{\rm NN}}$=5.02 TeV. This observable provides a new tool to investigate the transverse gluonic structure at low Bjorken-x.
Moreover, a new rapidity-differential measurement of the coherent photoproduction of $\rm{J/\psi}$ at midrapidity in Pb–Pb UPCs at $\sqrt{s_{\rm NN}}$=5.02 TeV is reported. This result complements the ALICE measurement of the coherent $\rm{J/\psi}$ cross section at forward rapidity allowing us to provide stringent constraints on nuclear gluon shadowing and saturation models at small Bjorken-x.
In addition, prospects for heavy vector meson photoproduction measurements in LHC Run 3 and 4 will be presented.
