2025/10/27 by Fukuyama, Takeshi
#FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph)
paper · doi:10.48550/arxiv.2510.22962
The QCD axion is investigated within the minimal supersymmetric SO(10) grand unified theory, where the Yukawa sector involves Higgs multiplets \bf 10 and \bf 126. The relative phase between the VEVs of (\bf 10,1,3)⊂\bf 126 and (\bf 10,1,3)⊂\bf 126 under \rm SU(4)C×\rm SU(2)L×\rm SU(2)R is identified with the axion. The Peccei-Quinn and B-L symmetry breaking scales coincide through |⟨ΔR⟩|=|⟨ΔR⟩|. The scalar partner of the lightest right-handed neutrino plays the role of the inflaton, realizing hybrid inflation consistent with the observed CMB density fluctuations. After inflation, both fields acquire VEVs, and the domain-wall problem is resolved through the Lazarides-Shafi mechanism, which naturally restricts the model to three generations.