# Inflation from Supersymmetry Breaking

## TL;DR

This paper proposes a supersymmetry-breaking inflation model where the sgoldstino acts as the inflaton, utilizing R-symmetry to satisfy slow-roll conditions and produce small field inflation consistent with observations.

## Contribution

It introduces a novel inflation framework driven by supersymmetry breaking with R-symmetry, avoiding the eta-problem and predicting specific ranges for tensor-to-scalar ratio and inflation scale.

## Key findings

- Models align with cosmological data.
- Predict tensor-to-scalar ratio between 10^{-9} and 10^{-4}.
- Inflation scale between 10^{10} and 10^{12} GeV.

## Abstract

We explore the possibility that inflation is driven by supersymmetry breaking with the superpartner of the goldstino (sgoldstino) playing the role of the inflaton. Moreover, we impose an R-symmetry that allows to satisfy easily the slow-roll conditions, avoiding the so-called $\eta$-problem, and leads to two different classes of small field inflation models; they are characterised by an inflationary plateau around the maximum of the scalar potential, where R-symmetry is either restored or spontaneously broken, with the inflaton rolling down to a minimum describing the present phase of our Universe. To avoid the Goldstone boson and remain with a single (real) scalar field (the inflaton), R-symmetry is gauged with the corresponding gauge boson becoming massive. This framework generalises a model studied recently by the present authors, with the inflaton identified by the string dilaton and R-symmetry together with supersymmetry restored at weak coupling, at infinity of the dilaton potential. The presence of the D-term allows a tuning of the vacuum energy at the minimum. The proposed models agree with cosmological observations and predict a tensor-to-scalar ratio of primordial perturbations $10^{-9}\lesssim r\lesssim 10^{-4}$ and an inflation scale $10^{10}$ GeV $\lesssim H_*\lesssim 10^{12}$ GeV. $H_*$ may be lowered up to electroweak energies only at the expense of fine-tuning the scalar potential.