Insights into Gravitinos Abundance, Cosmic Strings and Stochastic Gravitational Wave Background

TL;DR

This paper explores D-term inflation in supergravity, analyzing gravitino production, reheating dynamics, and gravitational waves from cosmic strings to understand early universe conditions and constraints.

Contribution

It provides a detailed study of gravitino abundance, reheating effects, and gravitational wave signals from cosmic strings within a supergravity inflation model.

Findings

Gravitino production depends on the reheating equation of state.

Cosmic string-generated gravitational waves constrain inflation energy scales.

Reheating temperature influences dark matter relic density.

Abstract

In this paper, we investigate D-term inflation within the framework of supergravity, employing the minimal K\"{a}hler potential. Following previous studies that revealed that this model can overcome the $\eta$-problem found in F-term models, we explore reheating dynamics and gravitino production, emphasizing the interplay between reheating temperature, spectral index, and gravitino abundance. Our analysis indicates that gravitino production is sensitive to the equation of state during reheating, affecting the reheating temperature and subsequent dark matter relic density. Furthermore, we analyze gravitational waves generated by cosmic strings, providing critical constraints on early Universe dynamics and cosmic string properties, the energy scales of both inflation and string formation influence the stochastic gravitational wave background (SGWB) generated by these cosmic strings.