SU(5) Unification without Proton Decay

TL;DR

This paper presents a four-dimensional SU(5) grand unified theory where the proton remains stable, achieved through specific field representations and symmetry breaking, aligning with current experimental constraints without fine-tuning.

Contribution

It introduces a novel SU(5) GUT model that ensures proton stability without requiring proton decay, differing from traditional models.

Findings

Proton remains stable in the model due to specific parameter relations.

The model satisfies current experimental constraints without fine-tuning.

All non-Standard Model fields are heavy, consistent with observations.

Abstract

We construct a four-dimensional SU(5) grand unified theory in which the proton is stable. The Standard Model leptons reside in the 5 and 10 irreps of SU(5), whereas the quarks live in the 40 and 50 irreps. The SU(5) gauge symmetry is broken by the vacuum expectation values of the scalar 24 and 75 irreps. All non-Standard Model fields are heavy. Stability of the proton requires three relations between the parameters of the model to hold. However, abandoning the requirement of absolute proton stability, the model fulfills current experimental constraints without fine-tuning.