Open charm production in heavy ion collisions and the color glass condensate

Abstract We consider the production of open charm in heavy ion collisions in the framework of the color glass condensate. In the central rapidity region at RHIC, for the charm quark yield we expect N coll (number of collisions) scaling in the absence of final-state effects. At higher energies, or forward rapidities at RHIC, the saturation scale exceeds the charm quark mass; we find that this results in the approximate N part (number of participants) scaling of charm production in AA collisions and N part A scaling in p(d)A collisions, similarly to the production of high- p T gluons discussed earlier. We also show that the saturation phenomenon makes spectra harder as compared to the naive parton model approach. We then discuss the energy loss of charm quarks in hot and cold media and argue that the hardness of the spectrum implies very slow dependence of the quenching factor on p T .