Gravitino production during preheating

TL;DR

This paper investigates gravitino production during preheating after inflation using non-perturbative methods, focusing on helicity states, calculating spectra, and comparing results with nucleosynthesis constraints.

Contribution

It applies the Bogolyubov technique to compute gravitino production in a supergravity model during preheating, simplifying the problem to Dirac fermions.

Findings

Calculated gravitino spectrum and number density.

Compared production results with nucleosynthesis bounds.

Identified constraints on supergravity models from gravitino production.

Abstract

We study the production of gravitinos during the preheating era after inflation by means of the non-perturbative Bogolyubov technique. Considering only the helicity $\pm 3/2$ states, the problem is reduced to the simpler Dirac fermions case. We calculate the production in a particular supergravity model in an expanding universe and obtain the spectrum and number density. Finally we compare the results with the nucleosynthesis bounds and extract some consequences.