Fully Testable Axion Dark Matter within a Minimal $SU(5)$ GUT

TL;DR

This paper proposes a minimal $SU(5)$ GUT model with a global $U(1)$ Peccei-Quinn symmetry predicting an ultralight axion dark matter candidate within a specific mass range, testable by upcoming experiments.

Contribution

It introduces a minimal GUT framework that simultaneously addresses gauge unification, fermion masses, and axion dark matter within a narrow mass window, linking theory with multiple experimental probes.

Findings

Predicts axion mass in [0.1, 4.7] neV range.

Identifies experimental avenues for testing the model.

Connects GUT constraints with dark matter phenomenology.

Abstract

We present a minimal Grand Unified Theory model, based on $SU(5)$ gauge symmetry and a global $U(1)$ Peccei-Quinn symmetry, that predicts the existence of an ultralight axion dark matter within a narrow mass range of $m_a\in[0.1,\,4.7]\,$neV. This mass window is determined through an interplay between gauge coupling unification constraints, partial proton decay lifetime limits, and the need to reproduce the experimentally observed fermion mass spectrum. The entire parameter space of the proposed model will be probed through a synergy between several low-energy experiments that look for proton decay (Hyper-Kamiokande), axion dark matter through axion-photon coupling (ABRACADABRA and DMRadio-GUT) and nucleon electric dipole moments (CASPEr Electric).