Orateur
Description
Ultra-relativistic heavy-ion collisions are an important tool to investigate the Quark-Gluon Plasma predicted by the theory of Quantum Chromo-Dynamics. It is also possible to use these collisions to study poorly known gluon shadowing effects at low Bjorken-$x$ values. Indeed Ultra-Peripheral Collisions (UPC) between two Pb nuclei, in which the impact parameter is larger than the sum of their radii, provide a useful way to study photonuclear reactions. Thanks to the data collected during Run2 by the ALICE Collaboration, a study based of the angular modulation of the muons originating from decays of photoproduced J$/\psi$ mesons is being performed in Lyon at forward rapidity. The implementation of the Muon Forward Tracker detector in ALICE for Run 3 and Run 4 at forward rapidity will improve the resolution and thus allow more precise studies of the photoproduction in UPC.
