Suppression of quarkonium production in heavy-ion collisions at RHIC and LHC

A model for the production of quarkonium states in the mid-rapidity region at the RHIC and LHC energy range is presented which explores well understood properties of quantum chromodynamics only. An increase of the quarkonium hadronization time with the initial energy leads to a gradual change of the most important phenomena from fixed target to collider energies. We evaluate nuclear effects in the quarkonium production due to medium modification of the momentum distribution of the heavy quarks produced in the hard interactions, i.e. due to the broadening of the transverse momentum distribution. Other nuclear effects, i.e. nuclear shadowing and parton energy loss, are also evaluated.