Axion and right-handed neutrino in the minimal SUSY SO(10) model

The connection between the axion and right-handed neutrinos is explored inthe framework of the minimal SUSY SO(10) model. The former is related to thePeccei-Quinn (PQ) solution to the strong CP problem and the latter is to thelight Majorana neutrinos through the see-saw mechanism. In this model, arelative phase between $({\bf 10,1,3}) (\equiv {\bf \bar{\Delta}}_R) \subset{\bf \bar{126}}$ and $({\bf \bar{10},1,3}) (\equiv {\bf \Delta}_R) \subset {\bf126}$ multiplets of ${\rm SU}(4) \times {\rm SU}(2)_L \times {\rm SU}(2)_R\subset {\rm SO}(10)$ becomes a physical degree of freedom identified with theaxion. Then, the PQ symmetry breaking scale ($\Lambda_{\rm PQ}$) and the $B-L$symmetry breaking scale ($\Lambda_{\rm B-L}$) coincide through the VEV of ${\bf\bar{\Delta}}_R$. The scalar partner of the lightest right-handed neutrino isregarded as the inflaton, which gives a consistent density fluctuation for theCMB.Comment: 8 pages, no figure; the version to appear in JHE