  For weakly bound quarkonia, we rederive the next-to-leading order cross
sections of quarkonium dissociation by partons that include the hard thermal
loop (HTL) resummation. Our results calculated with an effective vertex from
the Bethe-Salpeter amplitude reduce to those obtained by potential
nonrelativistic QCD (pNRQCD) in the relevant kinematical limit, and they can be
used in a wide temperature range applicable to heavy quark systems in heavy ion
collisions. Based on the lattice computation of the temperature-dependent
binding energy, our numerical analysis on $\Upsilon(1S)$ indicates that at high
temperature the dominant mechanism for quarkonium dissociation is inelastic
parton scattering as expected in the quasifree approximation, while it is the
gluo-dissociation at low temperature. By comparing with the momentum diffusion
coefficient of a heavy quark, we discuss possible O(g) corrections to the
next-to-leading order thermal width.
