J/\psi\ and \psi' production in proton(deuteron)-nucleus collisions: lessons from RHIC for the proton-lead LHC run

Abstract

We study the impact of different cold nuclear matter effects both on J/\psi\ and \psi' production, among them the modification of the gluon distribution in bound nucleons, commonly known as gluon shadowing, and the survival probability for a bound state to escape the nucleus --the nuclear absorption. Less conventional effects such as saturation and fractional energy loss are also discussed. We pay a particular attention to the recent PHENIX preliminary data on \psi' production in dAu collisions at sqrt{s}=200 GeV, which show a strong suppression for central collisions, 5 times larger than the one obtained for J/\psi\ production at the same energy. We conclude that none of the abovementioned mechanisms can explain this experimental result.

Comments: 4 pages, 2 tables, 2 figures, contribution to Rencontres du Vietnam, 'Heavy Ion Collisions in the LHC Era', 15-21 July 2012, Quy Nhon, Vietnam