Theoretical Uncertainties in Proton Lifetime Estimates

TL;DR

This paper reviews the main theoretical uncertainties affecting proton lifetime predictions in non-supersymmetric grand unified theories, highlighting the limited scenarios where next-to-leading order calculations are meaningful.

Contribution

It identifies the primary sources of uncertainties in proton lifetime estimates within conservative, non-supersymmetric GUT frameworks, emphasizing the minimal SO(10) model as most promising.

Findings

Many uncertainties are too severe for reliable NLO predictions.

The minimal renormalizable SO(10) GUT is the most promising scenario.

NLO approach is only sensible in few specific models.

Abstract

We recapitulate the primary sources of theoretical uncertainties in proton lifetime estimates in renormalizable, four-dimensional and non-supersymmetric grand unifications that represent the most conservative framework in which this question may be addressed at the perturbative level. We point out that many of these uncertainties are so severe that there are only very few scenarios in which an NLO approach, as crucial as it is for a real testability of any specific model, is actually sensible. Among these, the most promising seems to be the minimal renormalizable SO(10) GUT whose high-energy gauge symmetry is spontaneously broken by the adjoint and the five-index antisymmetric irreducible representations.