A Minimal Inflation Scenario

TL;DR

This paper proposes a minimal supergravity-based inflation model where the inflaton is the scalar component of the Goldstino superfield, linking inflation dynamics directly to supersymmetry breaking scale and solving the eta-problem without fine-tuning.

Contribution

It introduces a novel minimal inflation scenario based on supersymmetry breaking properties, with a single free parameter, and offers a new exit and reheating mechanism.

Findings

Supersymmetry breaking scale estimated at 10^{12-14} GeV.

Inflation model solves eta-problem without fine-tuning.

Model-independent approach using symmetry properties.

Abstract

We elaborate on a minimal inflation scenario based entirely on the general properties of supersymmetry breaking in supergravity models. We identify the inflaton as the scalar component of the Goldstino superfield. We write plausible candidates for the effective action describing this chiral superfield. In particular the theory depends (apart from parameters of O(1)) on a single free parameter: the scale of supersymmetry breaking. This can be fixed using the amplitude of CMB cosmological perturbations and we therefore obtain the scale of supersymmetry breaking to be 10^{12-14} GeV. The model also incorporates explicit R-symmetry breaking in order to satisfy the slow roll conditions. In our model the eta-problem is solved without extra fine-tuning. We try to obtain as much information as possible in a model independent way using general symmetry properties of the theory's effective action, this leads to a new proposal on how to exit the inflationary phase and reheat the Universe.