Sgoldstino inflation

TL;DR

This paper explores the potential of the sgoldstino, the superpartner of the goldstino, as the driver of cosmic inflation within supergravity frameworks, highlighting its decoupling properties and analyzing various inflation scenarios.

Contribution

It introduces a simplified single complex scalar model for sgoldstino inflation that captures multifield effects and discusses stability constraints and fine-tuning issues in supergravity inflation models.

Findings

Sgoldstino decouples from other fields, simplifying inflation models.

Two-field model effectively describes multifield inflation phenomenology.

Examples of small, large, and hybrid sgoldstino inflation scenarios provided.

Abstract

We discuss the possibility that inflation is driven by the sgoldstino, the superpartner of the goldstino. Unlike in generic supergravity scenarios, the sgoldstino decouples from all other fields in the theory, which allows for a simple and robust inflationary model. We argue that the two-field model given by this single complex scalar correctly captures the full multifield inflationary phenomenology. On the other hand, the assumption of stability, along the entire inflationary trajectory, of the supersymmetry-preserving sector that is integrated out leads to supplementary constraints on the parent supergravity. We investigate small field, large field and hybrid sgoldstino inflation scenarios and provide some working examples. They are subject to the usual fine-tuning issues that are common to all supergravity models of inflation. We comment on some other recently proposed sgoldstino inflation models.