Axion mass prediction from minimal grand unification

Abstract

We propose a minimal realization of the Peccei Quinn mechanism in a realistic SU(5) model, where the axion mass is directly connected to the grand-unification scale. By taking into account constraints from proton decay, collider searches and gauge coupling unification, we predict the axion mass: ma ∈ [4.8, 6.6] neV. The upper bound can be relaxed up to ma < 330 neV, at the cost of tuning the flavour structure of the proton decay operators. The predicted mass window will be complementarily probed by the axion dark matter experiments ABRACADABRA and CASPER-Electric, which could provide an indirect evidence for the scale of grand unification before the observation of proton decay.

Several Problems in Particle Physics and Cosmology Solved in One SMASH

“…However, there are viable extensions in which particles in Model 5 F 10 F 24 F 5 H 5 H 24 H miniSU(5)PQ 1 1 1 −2 2 2 Table 3. Field content and PQ charge assignments in the PQ-extended SU (5) model of [58].…”

“…This generates masses for the light neutrinos through a combination of the type I and III seesaw mechanisms, and also allows for baryogenesis from leptogenesis. When extending this viable SU (5) model to accommodate a global PQ symmetry with its corresponding axion [58], one has a SMASH-type construction with the complex scalar in the 24 H containing the axion and acting as a Majoron. The Lagrangian of this model, which we will refer to as miniSU(5)PQ, contains the following interactions (written only schematically),…”

“…The smallness of the axion mass in this model implies that the axion can be identified with dark matter only if the Peccei-Quinn symmetry is broken before or during inflation and not Table 4. Axion predictions in SU (5) × U (1) PQ [58] and SO(10) × U (1) PQ models [20]: Axion decay constant f A , domain wall number N DW , coupling to the photon C Aγ , and tree-level couplings to quarks and charged leptons C Ai , i = u, ..., t, e, .., τ . In the SU (5) theory, tan β = v H /v H , while for the SO(10) Table 5.…”

An axion-like particle from an SO(10) seesaw with U(1)

“…Recently there has been considerable interest in the occurrence of axion-like particles [1][2][3] including the appearance in model building af anomalous U (1) symmetries with a Stueckelberg field [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19]. In this paper we examine the simplest GUT example where this phenomenon is closely related to the see-saw mechanism [20] for generating the neutrino masses and may provide a link between axions and right-handed neutrinos.…”

Spontaneous proton decay and the origin of Peccei–Quinn symmetry

“…This allows one, for instance, to define models with very different axion-photon coupling [22,23]. In addition, recently, a number of authors have made some insights in relating the PQ symmetry and the axion to flavor physics ([24-36]) 1 , unification [38][39][40][41][42], inflation ( [43][44][45][46][47][48] and neutrino mass generation ( [30,[49][50][51][52][53]).…”