  Effects of heavy fields on primordial spectra of curvature perturbations are
discussed in inflationary models with a sudden turning trajectory. When heavy
fields are excited after the sudden turn and oscillate around the bottom of the
potential, the following two effects are generically induced: deformation of
the inflationary background spacetime and conversion interactions between
adiabatic and isocurvature perturbations, both of which can affect the
primordial density perturbations. In this paper, we calculate primordial
spectra in inflationary models with sudden turning potentials taking into
account both of the two effects appropriately. We find that there are some
non-trivial correlations between the two effects in the power spectrum and, as
a consequence, the primordial scalar power spectrum has a peak around the scale
exiting the horizon at the turn. Though both effects can induce parametric
resonance amplifications, they are shown to be canceled out for the case with
the canonical kinetic terms. The peak feature and the scale dependence of
bispectra are also discussed.
