Curvature perturbation spectra from waterfall transition, black hole
  constraints and non-Gaussianity
  We carried out numerical calculations of a contribution of the waterfall
field to the primordial curvature perturbation (on uniform density
hypersurfaces) $\zeta$, which is produced during waterfall transition in hybrid
inflation scenario. The calculation is performed for a broad interval of values
of the model parameters. We show that there is a strong growth of amplitudes of
the curvature perturbation spectrum in the limit when the bare mass-squared of
the waterfall field becomes comparable with the square of Hubble parameter. We
show that in this limit the primordial black hole constraints on the curvature
perturbations must be taken into account. It is shown that, in the same limit,
peak values of the curvature perturbation spectra are far beyond horizon, and
the spectra are strongly non-Gaussian.
