  In a weak-coupling effective field theory framework we study quarkonium
dissociation induced by inelastic scattering with partons in the medium. This
is the dominant dissociation process for temperatures such that the Debye mass
is larger than the binding energy. We evaluate the dissociation cross section
and the corresponding thermal decay width. At leading order we derive a
convolution formula relating the two, which is consistent with the optical
theorem and QCD at finite temperature. Bound state effects are systematically
included. They add contributions to the cross section and width that are beyond
a quasi-free approximation, whose validity is critically reviewed. For
temperatures such that the Debye mass is smaller than the binding energy, the
dominant dissociation mechanism is gluo-dissociation consisting in quarkonium
dissociation induced by the absorbtion of a gluon from the medium. We calculate
the gluo-dissociation cross section and width at next-to-leading-order
accuracy.
