SUPER-Screening

TL;DR

This paper develops a supersymmetric framework for scalar-tensor modified gravity models, revealing that supersymmetry breaking typically suppresses observable effects, with no-scale models being uniquely capable of avoiding this suppression.

Contribution

It introduces a supersymmetric embedding of screened modified gravity models and analyzes their features, showing how supersymmetry breaking impacts their observable signatures.

Findings

Supersymmetry breaking induces a soft mass for the scalar, preventing observable signatures.

No-scale models can evade the suppression caused by supersymmetry breaking.

A new mechanism generates a small cosmological constant via a Fayet-Iliopoulos term.

Abstract

We present a framework for embedding scalar-tensor models of screened modifed gravity such as chameleons, symmetrons and environmental dilatons into global supersymmetry. This achieved by secluding the dark sector from both the observable and supersymmetry breaking sectors. We examine the resulting supersymmetric features in a model-independent manner and find that, when the theory follows from an underlying supergravity, the mediation of supersymmetry breaking to the dark sector induces a soft mass for the scalar of order the gravitino mass. This is enough to forbid the construction of supersymmetric symmetrons and ensures that when other screening mechanisms operate, no object in the universe is unscreened thereby precluding any observable signatures. In view of a possible origin of modifed gravity within fundamental physics, we find that no-scale models are the only ones that can circumvent these features. We also present a novel mechanism where the coupling of the scalar to two other scalars charged under U(1) can dynamically generate a small cosmological constant at late times in the form of a Fayet-Iliopoulos term.