Signatures of the color glass condensate in J/psi production off nuclear targets

摘要

We consider the J/psi production in proton (deuteron)-nucleus collisions at high energies. We argue that the production mechanism in this case is different from that in pp collisions due to gluon saturation in the nucleus and formation of the color glass condensate. At forward rapidities (in the proton fragmentation region), the production of J/psi is increasingly suppressed both as a function of rapidity and centrality. On the other hand, at backward rapidities at RHIC (in the fragmentation region of the nucleus) the coherent effects lead to a modest enhancement of the production cross section, with the nuclear modification factor R-J/psi increasing with centrality. We find that the J/psi production cross section exhibits at forward rapidities the limiting fragmentation scaling established previously for soft processes; in the energy range studied experimentally, it manifests itself as an approximate "chi(F) scaling". (c) 2006 Elsevier B.V. All rights reserved.