Quarkonia Photoproduction at Nucleus Colliders

Exclusive photo production of heavy quarkonia in high-energy ultraperipheral ion-ion interactions (gamma A, V A, where V = J/psi, Gamma 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 [1], as well as full simulation-reconstruction studies of photo-produced Gamma in Pb-Pb interactions at the LHC [2].