The static potential between two color charges is screened at finite temperature. This could lead to an anomalous suppression of heavy-quark bound states (J/Psi, Upsilon) in heavy-ion collisions where quark-gluon plasma is expected to be formed. In this talk, the total cross section of a heavy quarkonium on a hadron target in perturbative QCD, including target mass corrections, is determined. The method relies on the analytical continuation of the operator product expansion of the forward scattering amplitude, obtained long ago by Bhanot and Peskin. The cross section has a simple partonic form, which allows one to investigate the phenomenology of J/psi and Upsilon dissociation by both pions and protons. Finally, I will introduce a model to describe possible medium effects on the heavy-quarkonium interaction by taking explicitly the temperature dependence of the heavy-quark potential into account.

LPTHE, Jussieu