Gravitino cosmology in supersymmetric warm inflation

TL;DR

This paper investigates gravitino production during supersymmetric warm inflation, revealing that continuous thermal production and lower radiation temperatures can alleviate the gravitino problem, with implications for baryogenesis and standard reheating.

Contribution

It provides a comprehensive analysis of gravitino abundance evolution during warm inflation, including effects of supersymmetry breaking and transition to radiation domination, which was not fully addressed before.

Findings

Continuous thermal production increases gravitino yield.

Lower radiation temperatures can alleviate the gravitino problem.

Dissipative effects can produce baryon asymmetry despite gravitino constraints.

Abstract

In supersymmetric models of warm inflation, the large temperature of the radiation bath produced by the dissipative motion of the inflaton field may induce a significant thermal abundance of potentially dangerous gravitinos. While previous discussions of this problem focused on gravitino production only at the end of warm inflation, similarly to conventional reheating scenarios, we study the full evolution of the gravitino abundance during and after inflation for simple monomial potentials, taking into account the enhanced gravitino and possibly gaugino masses due to supersymmetry breaking during inflation and the smooth transition into a radiation-dominated era. We find, on one hand, that the continuous thermal production increases the gravitino yield, although, on the other hand, `freeze-out' occurs at temperatures much lower than previously estimated. Moreover, for sufficiently strong dissipation, which allows for sub-planckian inflaton values, the lower radiation temperature significantly alleviates and possibly solves the gravitino problem, with a baryon asymmetry being nevertheless produced through dissipative effects. Our analysis may also be relevant to standard reheating as an oscillating inflaton will also change the gravitino mass, potentially modifying the produced gravitino yield.