Inflation with racetrack superpotential and matter field

TL;DR

This paper explores racetrack inflation models coupled with matter fields within a supersymmetric framework, demonstrating new classes of models with relaxed fine-tuning and discussing gravitino mass implications.

Contribution

It introduces fully supersymmetric racetrack inflation models with matter fields as sources of supersymmetry breaking and uplifting, analyzing different SUSY breaking mechanisms and their effects.

Findings

Matter field dominance in inflation models.

Relaxed fine-tuning compared to original models.

Difficulty in achieving light gravitino with volume modulus dominance.

Abstract

Several models of inflation with the racetrack superpotential for the volume modulus coupled to a matter field are investigated. In particular, it is shown that two classes of racetrack inflation models, saddle point and inflection point ones, can be constructed in a fully supersymmetric framework with the matter field F-term as a source of supersymmetry breaking and uplifting. Two models of F-term supersymmetry breaking are considered: the Polonyi model and the quantum corrected O'Raifeartaigh model. In the former case, both classes of racetrack inflation models differ significantly from the corresponding models with non-supersymmetric uplifting. The main difference is a quite strong dominance of the inflaton by the matter field. In addition, fine-tuning of the parameters is relaxed as compared to the original racetrack models. In the case of the racetrack inflation models coupled to the O'Raifeartaigh model, the matter field is approximately decoupled from the inflationary dynamics. In all of the above models the gravitino mass is larger than the Hubble scale during inflation. The possibility of having the gravitino much lighter than the Hubble scale is also investigated. It is very hard to construct models with light gravitino in which the volume modulus dominates inflation. On the other hand, models in which the inflationary dynamics is dominated by the matter field are relatively simple and seem to be more natural.