# Resonant particle production during inflation: a full analytical study

## TL;DR

This paper provides an exact analytical framework for studying particle production during inflation, focusing on the resulting features in primordial correlators and extending the analysis to gravitationally coupled sectors.

## Contribution

It offers a unified formalism with exact expressions for the shape and amplitude of inflationary signatures caused by particle bursts, improving upon previous numerical approaches.

## Key findings

- Exact analytic expressions for the bump in power spectrum and bispectrum.
- Validation of the dominant role of rescattering effects.
- Extension of analysis to gravitationally coupled sectors.

## 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.