  A binary mixture made of heavy and light inelastic hard spheres in the free
cooling state is considered. First, the regions in the parameter space where
the partial granular temperature of the heavy species is larger (or smaller)
than that of the light species are analyzed. Next, the asymptotic behavior of
the mean square velocity ratio in the disparate-mass limit is investigated,
assuming different scaling laws for the parameters of the mixture. It is seen
that two general classes of states are possible: a "normal" state and an
"ordered" state, the latter representing a strong breakdown of energy
equipartition.
