Minimal Supersymmetric SU(5) and Gauge Coupling Unification at Three Loops

TL;DR

This paper performs a detailed three-loop analysis of gauge coupling unification in minimal supersymmetric SU(5), incorporating threshold corrections and experimental uncertainties, confirming its viability against proton decay constraints.

Contribution

It provides the first comprehensive three-loop calculation of gauge coupling unification in minimal supersymmetric SU(5) including threshold effects and uncertainties.

Findings

Minimal supersymmetric SU(5) remains consistent with current proton decay limits.

Three-loop corrections significantly refine unification predictions.

Experimental uncertainties impact the predicted super-heavy mass spectrum.

Abstract

We consider the relations between the gauge couplings at the electroweak scale and the high scale where unification of the three gauge couplings is expected. Threshold corrections are incorporated both at the supersymmetric and at the grand unified scale and, where available three-loop running and two-loop decoupling are employed. We study the impact of the current experimental uncertainties of the coupling constants and the supersymmetric mass spectrum on the prediction of the super-heavy masses within the so-called minimal supersymmetric SU(5). As a main result of the three-loop analysis we confirm that minimal supersymmetric SU(5) cannot be ruled out by the current experimental data on proton decay rates.