Inflation from Supergravity with Gauged R-symmetry in de Sitter Vacuum

TL;DR

This paper explores a supergravity model with gauged R-symmetry that can produce inflation compatible with current cosmological data, while maintaining standard low-energy phenomenology.

Contribution

It demonstrates that a modified Kähler potential inspired by NS5-brane instantons allows the dilaton to serve as the inflaton in a supergravity framework with a de Sitter vacuum.

Findings

The model achieves an inflationary plateau consistent with observations.

Inflation is possible with a specific Kähler potential modification.

Low energy phenomenology remains unaffected at the potential's minimum.

Abstract

We study the cosmology of a recent model of supersymmetry breaking, in the presence of a tuneable positive cosmological constant, based on a gauged shift symmetry of a string modulus that can be identified with the string dilaton. The minimal spectrum of the `hidden' supersymmetry breaking sector consists then of a vector multiplet that gauges the shift symmetry of the dilaton multiplet and when coupled to the MSSM leads to a distinct low energy phenomenology depending on one parameter. Here we study the question if this model can also lead to inflation by identifying the dilaton with the inflaton. We find that this is possible if the K\"ahler potential is modified by a term that has the form of NS5-brane instantons, leading to an appropriate inflationary plateau around the maximum of the scalar potential, depending on two extra parameters. This model is consistent with present cosmological observations without modifying the low energy particle phenomenology associated to the minimum of the scalar potential.