Stable Non-Supersymmetric Throats in String Theory

TL;DR

This paper constructs a broad class of stable, non-supersymmetric AdS-like throat geometries in string theory via orbifolds, providing a foundation for realistic models like Randall-Sundrum and composite Higgs scenarios.

Contribution

It introduces a method to create stable, non-supersymmetric throat geometries in string theory with potential applications in phenomenology.

Findings

Large hierarchy of energy scales remains stable.

Dual gauge theories lack relevant singlet operators.

Embedding in compact spaces preserves stability.

Abstract

We construct a large class of non-supersymmetric AdS-like throat geometries in string theory by taking non-supersymmetric orbifolds of supersymmetric backgrounds. The scale of SUSY breaking is the AdS radius, and the dual field theory has explicitly broken supersymmetry. The large hierarchy of energy scales in these geometries is stable. We establish this by showing that the dual gauge theories do not have any relevant operators which are singlets under the global symmetries. When the geometries are embedded in a compact internal space, a large enough discrete subgroup of the global symmetries can still survive to prevent any singlet relevant operators from arising. We illustrate this by embedding one case in a non-supersymmetric orbifold of a Calabi-Yau manifold. These examples can serve as a starting point for obtaining Randall-Sundrum models in string theory, and more generally for constructing composite Higgs or technicolor-like models where strongly coupled dynamics leads to the breaking of electro-weak symmetry. Towards the end of the paper, we briefly discuss how bulk gauge fields can be incorporated by introducing D7-branes in the bulk, and also show how the strongly coupled dynamics can lead to an emergent weakly coupled gauge theory in the IR with matter fields including scalars.