  Heavy quarkonia production is predicted to be sensitive to the formation of
the quark gluon plasma in relativistic heavy ion collisions via competing
mechanisms such as color screening and/or quark recombination. During 2004 and
2005 RHIC data taking periods, the PHENIX collaboration has measured jpsi decay
into lepton pairs both at mid and forward rapidity in Au+Au and Cu+Cu
collisions at $\sqrt{s_{NN}}$=200 GeV. We present the jpsi nuclear modification
factor and the $\jpsi$ mean square transverse momentum as a function of the
collision centrality for both systems, as well as the rapidity dependence of
the jpsi yield for different centrality classes. It is compared to different
theoretical predictions. All Au+Au and Cu+Cu results shown here are
preliminary.
