Gravitino Production After Inflation

TL;DR

This paper explores how gravitinos are produced after inflation through a non-thermal mechanism involving interactions with an oscillating inflaton field, with implications for inflationary model constraints.

Contribution

It reformulates supergravity to analyze gravitino production, revealing that production is not suppressed by gravitational coupling and depends on the underlying theory.

Findings

Gravitino production can be copiously generated post-inflation.

Production probability is not suppressed by gravitational coupling.

Constraints on inflationary models depend on the theory's specifics.

Abstract

We investigate the production of gravitinos in a cosmological background. Gravitinos can be produced during preheating after inflation due to a combined effect of interactions with an oscillating inflaton field and absence of conformal invariance. In order to get insight on conformal properties of gravitino we reformulate phenomenological supergravity in SU(2,2|1)-symmetric way. The Planck mass and F- and D-terms appear via the gauge-fixed value of a superfield that we call conformon. We find that in general the probability of gravitino production is not suppressed by the small gravitational coupling. This may lead to a copious production of gravitinos after inflation. Efficiency of the new non-thermal mechanism of gravitino production is very sensitive to the choice of the underlying theory. This may put strong constraints on certain classes of inflationary models.