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.