Cosmological Gravitino Production in Gauge Mediated Supersymmetry Breaking Models

TL;DR

This paper examines how gravitino production in gauge mediated supersymmetry breaking models affects cosmological constraints, highlighting the impact of messenger scale and the potential for high reheat temperatures.

Contribution

It provides a detailed analysis of gravitino relic density considering messenger sector effects, revealing conditions for high reheat temperatures without overclosure.

Findings

Messenger sector tightens bounds on reheat temperature.

Low messenger scale allows high reheat temperature with small gravitino density.

Relic gravitino density can be below critical density independently of reheat temperature.

Abstract

We study the cosmological gravitino production in gauge mediated supersymmetry breaking models, while properly taking into account the existence of the messenger mass scale. It is found that for sizable parameter range of the model the messenger sector contribution leads to more stringent upper bound on the reheat temperature obtained from the condition that the universe should not be overclosed by relic gravitinos. However it turns out that in the limit of relatively low messenger scale and large gravitino mass, the relic gravitino mass density can be smaller than the critical density independently of the reheat temperature, suggesting the possibility in this limit to have a high reheat temperature without the dilution of gravitinos at late time.