Axion Dark Matter, Proton Decay and Unification

TL;DR

This paper explores how grand unified theories can predict the QCD axion mass and proton decay rates, linking axion physics with proton decay observables in a minimal SU(5) GUT framework.

Contribution

It demonstrates a precise prediction of the axion mass within a specific GUT model and establishes a correlation with proton decay rates, providing testable experimental predictions.

Findings

Predicted axion mass range: 2-16 neV.

Estimated proton decay lifetime bounds: rom or proton decay channels.

The model is fully testable by upcoming axion and proton decay experiments.

Abstract

We discuss the possibility to predict the QCD axion mass in the context of grand unified theories. We investigate the implementation of the DFSZ mechanism in the context of renormalizable SU(5) theories. In the simplest theory, the axion mass can be predicted with good precision in the range $m_a = (2-16)$ neV, and there is a strong correlation between the predictions for the axion mass and proton decay rates. In this context, we predict an upper bound for the proton decay channels with antineutrinos, $\tau(p\to K^+ \bar{\nu}) \lesssim 4 \times 10^{37} \text{ yr}$ and $\tau(p \to \pi^+ \bar{\nu}) \lesssim 2 \times 10^{36}\text{ yr}$. This theory can be considered as the minimal realistic grand unified theory with the DFSZ mechanism and it can be fully tested by proton decay and axion experiments.