Heavy gravitino in hybrid inflation

TL;DR

This paper proposes a modified supersymmetric hybrid inflation model that suppresses the constant term during inflation, allowing for large gravitino masses without fine-tuning and relaxing cosmic string constraints.

Contribution

It introduces a dynamical field replacing the constant term, enabling successful inflation with large gravitino mass without severe initial condition tuning.

Findings

Successful inflation achieved with large gravitino mass

Reduced fine-tuning of initial conditions

Relaxed constraints from cosmic strings

Abstract

It is known that supersymmetric hybrid inflation model may require severe tunings on the initial condition for large gravitino mass of order 100 - 1000 TeV due to the constant term in the superpotential. We propose a modified hybrid inflation model, where the constant term is suppressed during inflation and generated after inflation by replacing a constant term with dynamical field. In this modified model, successful inflation consistent with large gravitino mass takes place without severe tunings on the initial condition. Constraint from cosmic strings is also relaxed.