Vector-Like Quarks and Leptons, SU(5) $\otimes$ SU(5) Grand Unification, and Proton Decay

TL;DR

This paper investigates a non-supersymmetric SU(5) x SU(5) grand unification model incorporating vector-like quarks and leptons, analyzing gauge coupling unification and its implications for proton decay, with potential observable decay modes.

Contribution

It introduces a minimal non-supersymmetric SU(5) x SU(5) model with vector-like fermions, demonstrating how gauge coupling unification can suppress proton decay and make certain decay modes experimentally accessible.

Findings

Gauge coupling unification is achievable with vector-like fermions.

Proton decay mode p -> e+ pi0 could be within experimental reach.

Intermediate scales from unification influence proton decay suppression.

Abstract

SU(5) $\otimes$ SU(5) provides a minimal grand unification scheme for fermions and gauge forces if there are vector-like quarks and leptons in nature. We explore the gauge coupling unification in a non-supersymmetric model of this type, and study its implications for proton decay. The properties of vector-like quarks and intermediate scales that emerge from coupling unification play a central role in suppressing proton decay. We find that in this model, the familiar decay mode $p \to e^+ \pi^0$ may have a partial lifetime within the reach of currently planned experiments.