J / ψ production in heavy ion collisions and gluon saturation

We calculate the inclusive J / ψ production in heavy ion collisions including the effects of gluon saturation in the wave functions of the colliding nuclei. We argue that the dominant production mechanism in proton-nucleus and nucleus-nucleus collisions for heavy nuclei is different from the one in hadron-hadron interactions. We find that the rapidity distribution of primary J / ψ production is more peaked around midrapidity than the analogous distribution in elementary pp collisions. We discuss the consequences of this fact on the experimentally observed J / ψ suppression in Au-Au collisions at RHIC energies.