Soft and hard QCD dynamics in hadroproduction of charmonium

Both hard and soft QCD dynamics are important in charmonium production, as presented here through a ncxt-to-leading order QCD matrix element calculation combined with the color evaporation model. The observed X-F and p distributions of J/psi, in hadroproduction at fixed target and pp collider energies arc reproduced. Quite similar results can also be obtained in a more phenomenologically useful Monte Carlo event generator where the perturbative production of cc pairs is instead obtained through leading order matrix elements and the parton shower approximation of the higher order processes. The soft dynamics may alternatively be described by the soft color interaction model, originally introduced in connection with rapidity gaps. We also discuss the relative rates of different charmonium states and introduce an improved model for mapping the continuous c mass spectrum on the physical charmonium resonances.