Removing instability of Polonyi-Starobinsky supergravity by adding FI term

TL;DR

This paper identifies an instability in the Polonyi-Starobinsky supergravity model of inflation and proposes a solution by incorporating a Fayet-Iliopoulos term to stabilize the potential.

Contribution

The authors introduce a Fayet-Iliopoulos term to remove the potential instability in the Polonyi-Starobinsky supergravity model of inflation.

Findings

Instability in the original PS supergravity model identified.

Adding FI term stabilizes the inflationary potential.

Potential for improved cosmological models with stable supergravity potentials.

Abstract

Polonyi-Starobinsky (PS) supergravity is the N=1 supergravity model of Starobinsky inflation with spontaneous supersymmetry breaking (after inflation) due to Polonyi superfield, and inflaton belonging to a massive vector supermultiplet. The PS model is used for an explicit realization of the (super-heavy) gravitino dark matter scenario in cosmology. We find a potential instability in this model, and offer a mechanism for its removal by adding a Fayet-Iliopoulos (FI) term.