Axion and Right-handed Neutrino in the Minimal SUSY SO(10) Model

Abstract

The connection between the axion and right-handed neutrinos is explored in the framework of the minimal SUSY SO(10) model. The former is related to the Peccei-Quinn (PQ) solution to the strong CP problem and the latter is to the light Majorana neutrinos through the see-saw mechanism. In this model, a relative phase between $(10,1,3)(\equiv {\bar{\mathbf{\Delta }}}_R)\subset \overline{126}$ and $(\overline{10},1,3)(\equiv {\mathbf{\Delta }}_R)\subset 126$ multiplets of $\mathrm{SU}(4)\times \mathrm{SU}(2{)}_L\times \mathrm{SU}(2{)}_R\subset \mathrm{SO}(10)$ becomes a physical degree of freedom identified with the axion. Then, the PQ symmetry breaking scale (${\Lambda }_{\mathrm{PQ}}$) and the $B-L$ symmetry breaking scale (${\Lambda }_{\mathrm{B}-\mathrm{L}}$) coincide through the VEV of ${\bar{\mathbf{\Delta }}}_R$. The scalar partner of the lightest right-handed neutrino is regarded as the inflaton, which gives a consistent density fluctuation for the CMB.

8 pages, no figure; the version to appear in JHEP