Speaker
Description
The high flux of quasi-real photons from fast moving lead ions at the LHC allows us to study photon-induced reactions in ultra-peripheral collisions (UPC) of Pb-Pb nuclei in a new kinematic regime. In addition, this flux makes it possible to study J/$\Psi$ exclusive photoproduction off protons in p-Pb collisions at the LHC. Measuring the scattering angle of the produced vector meson one can compute the centre-of-mass energy of the photon-proton or photon-Pb scattering. It is then possible to study with these collisions the energy evolution of the gluon content of the target.
The newest ALICE results on photoproduction of vector meson in UPC Pb-Pb and p-Pb collisions from LHC are presented. These results provide new stringent test to models of saturation and shadowing at small-x. The measurements are compared to the current models of this process.
