Charmonium Cold Nuclear matter effects: Latest results from PHENIX

Charmonium suppression in hot and dense nuclear matter has been argued to be a unique signature for the production of the quark gluon plasma (QGP). In order to search for this effect in heavy ion collisions one must have a clear understanding of the modifications present in the charmonium spectrum resulting from the interaction with normal cold nuclear matter. The PHENIX experiment has measured J/$\psi$'s spectrum from deuteron-gold (d-Au) interactions at $\sqrt{s}$=200GeV and compared these with a proton-proton baseline (2006 RHIC run) in order to constrain these cold nuclear matter effects. We will present the latest analysis from the 2008 RHIC run, with an integrated luminosity of ~80 nb$^{-1}$, compared to the 2.4 nb$^{-1}$ collected in the 2003 RHIC run.