An assessment of J/ψ formation in the light of initial RHIC data

Predictions of J/ψ formation at Relativistic Heavy Ion Collides (RHIC) via 'off-diagonal' combinations of charm and anticharm quarks in a region of colour deconfinement are confronted with initial data from the PHENIX collaboration. We find that the measured centrality behaviour places significant constraints on the various parameters which control model calculations of J/ψ formation. Within present statistical and systematic uncertainties, one can map out a region of parameter space within which the contribution of formation in a deconfined phase is allowed. As these uncertainties decrease and new data from d-Au interactions becomes available, it is expected that definitive tests for the presence of this formation mechanism will be possible. We anticipate that the rapidity and transverse momentum spectra will prove decisive for a final determination.