  The spatially homogeneous Boltzmann equation with hard potentials is
considered for measure valued initial data having finite mass and energy. We
prove the existence of \emph{weak measure solutions}, with and without angular
cutoff on the collision kernel; the proof in particular makes use of an
approximation argument based on the Mehler transform. Moment production
estimates in the usual form and in the exponential form are obtained for these
solutions. Finally for the Grad angular cutoff, we also establish uniqueness
and strong stability estimate on these solutions.
