2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/210995Exclusive photoproduction of heavy quarkonia in high-energy ultraperipheral ion-ion interactions (gamma A --> V A, where V = J/Psi,Upsilon and the nucleus A remains intact) offers a useful means to constrain the small-x nuclear gluon density. We discuss preliminary results on J/Psi photoproduction in Au-Au collisions at RHIC energies, as well as full simulation-reconstruction studies of photo-produced Upsilon's in Pb-Pb interactions at the LHC.4 pages, invited talk PHOTON'07 (Paris), Proceeds. to appear in Nucl. Phys. BNuclear ExperimentHigh Energy Physics - ExperimentNuclear Theorytext