Scalar leptoquark in SU(5)

TL;DR

This paper analyzes the minimal SU(5) model with a scalar leptoquark, deriving predictions for proton decay channels and establishing lower mass limits based on experimental constraints, which can be tested if proton decay is observed.

Contribution

It provides a model-dependent analysis of proton decay predictions in minimal SU(5) with a scalar leptoquark, including phase-independent ratios and mass bounds.

Findings

Proton decay widths depend only on known quark sector parameters and one phase.

The ratio of decay widths to pions and kaons is phase-independent and predicts suppression of pion channels.

A lower mass limit for the scalar leptoquark is established based on experimental stability constraints.

Abstract

We address the issue of model dependence of partial proton decays due to exchange of a single scalar leptoquark within a minimal viable SU(5) framework. The minimal setup predicts a flavor part of the proton decay widths for channels with anti-neutrinos in the final state to depend solely on the known masses and mixing parameters of the quark sector and one extra phase. We accordingly establish an accurate lower limit on the mass of the scalar leptoquark in connection with the relevant experimental constraints on the matter stability. The ratio of proton decay widths for channels with the positive pion and the positive kaon in the final state turns out to be phase independent and predicts strong suppression of the former width with respect to the latter one. Our results offer a possibility to test the minimal scenario if and when proton decay is observed.