Almost No-Scale Supergravity

TL;DR

This paper develops a 5D supergravity model implementing no-scale supersymmetry breaking without unstable moduli, featuring radion stabilization via Casimir energy and a realistic setup for gaugino-mediated supersymmetry breaking.

Contribution

It provides an explicit 5D supergravity framework realizing no-scale SUSY breaking with stabilized moduli and a realistic model for gaugino mediation.

Findings

Radion stabilized by Casimir energy from supergravity and hypermultiplets.

Visible sector SUSY breaking dominated by gravity and hypermultiplet loops.

Gaugino masses are smaller than scalar masses, with gravitino and moduli masses above the weak scale.

Abstract

We construct an explicit 5-dimensional supergravity model that realizes the "no scale" mechanism for supersymmetry breaking with no unstable moduli. Supersymmetry is broken by a constant superpotential localized on a brane, and the radion is stabilized by Casimir energy from supergravity and massive hypermultiplets. If the standard model gauge and matter fields are localized on a brane, then visible sector supersymmetry breaking is dominated by gravity loops and flavor-violating hypermultiplet loops, and gaugino masses are smaller than scalar masses. We present a realistic model in which the the standard model gauge fields are partly localized. In this model visible sector supersymmetry breaking is naturally gaugino mediated, while masses of the gravitino and gravitational moduli are larger than the weak scale.