  We study the possibility that large scale cosmological perturbations have
been generated during the domination and decay of a massive particle species
whose mass depends on the expectation value of a light scalar field. We discuss
the constraints that must be imposed on the field in order to remain light and
on the annihilation cross section and decay rate of the massive particles in
order for the mechanism to be efficient. We compute the resulting curvature
perturbations after the mass domination, recovering the results of Dvali,
Gruzinov, and Zaldarriaga in the limit of total domination. By comparing the
amplitude of perturbations generated by the mass domination to those originally
present from inflation, we conclude that this mechanism can be the primary
source of perturbations only if inflation does not rely on slow-roll
conditions.
