Minimal Supergravity Inflation without Slow Gravitino

TL;DR

This paper presents a supergravity inflation model using a cubic nilpotent superfield that avoids gravitino overproduction, but still faces the standard gravitino problem depending on the universe's thermal history.

Contribution

It introduces a minimal supergravity inflation model with a cubic nilpotent superfield that eliminates gravitino propagation issues.

Findings

Model is free from catastrophic gravitino production.

Standard gravitino problem remains depending on thermal history.

Viability depends on mass spectrum and cosmological conditions.

Abstract

We utilize a recently proposed cubic nilpotent superfield to realize inflation in supergravity with the minimal degrees of freedom: the inflaton, graviton, and massive gravitino. As an advantage, the resultant model is free from the catastrophic production of gravitinos due to its vanishing propagation speed. However, the model suffers from the standard gravitino problem, and its viability depends on the mass spectrum and the thermal history of the universe.