Doublet-Triplet Splitting in an SU(5) Grand Unification

TL;DR

This paper proposes a novel solution to the doublet-triplet splitting problem in supersymmetric SU(5) GUTs using the Hosotani mechanism, predicting light adjoint supermultiplets and potential collider signatures.

Contribution

It introduces a new mechanism for symmetry breaking in SU(5) GUTs that addresses the doublet-triplet splitting problem and predicts testable light supermultiplets.

Findings

Light adjoint chiral supermultiplets at TeV scale.

Gauge coupling unification can be maintained with additional particles.

Testable predictions for collider experiments.

Abstract

We present a new solution to the doublet-triplet splitting problem which also works in a supersymmetric SU(5) grand unified theory and is testable at TeV-scale collider experiments. In our model, the SU(5) symmetry is broken through the Hosotani mechanism. Thanks to the phase nature of the Hosotani-breaking, the "missing VEV" can be realized even in an SU(5) model. A general and distinctive prediction of this solution is the existence of light adjoint chiral supermultiplets with masses of the supersymmetry breaking scale. Though these disturb the gauge coupling unification, it can be recovered keeping the unified gauge coupling constant perturbative by introducing additional vector-like particles, which may be also observed in the upcoming collider experiments.