Title: Resonant particle production during inflation: a full analytical study,
Abstract: We revisit the study of the phenomenology associated to a burst of particle
production of a field whose mass is controlled by the inflaton field and
vanishes at one given instance during inflation. This generates a bump in the
correlators of the primordial scalar curvature. We provide a unified formalism
to compute various effects that have been obtained in the literature and
confirm that the dominant effects are due to the rescattering of the produced
particles on the inflaton condensate. We improve over existing results (based
on numerical fits) by providing exact analytic expressions for the shape and
height of the bump, both in the power spectrum and the equilateral bispectrum.
We then study the regime of validity of the perturbative computations of this
signature. Finally, we extend these computations to the case of a burst of
particle production in a sector coupled only gravitationally to the inflaton.