We investigate Higgs Parity Unification-a realization of SO (10) grand unification based on the Higgs Parity mechanism in which the Standard Model (SM) Higgs resides in a spinor representation. The theory has an intermediate left-right symmetric stage where the SU (2) R symmetry breaking scale is fixed by the vanishing of the SM Higgs quartic coupling. The strong CP problem is solved by parity. Gauge coupling unification successfully predicts αₛ (MZ) to within 1%. The spinor Higgs naturally leads to a seesaw origin for SM flavor observables. We identify a novel mechanism where large mixing of third generation fermions with additional heavy vector-like fermions accounts for the anarchical nature of the PMNS matrix and the lack of hierarchy in the neutrino mass spectrum, relative to the up-quarks. A fit to quark and lepton masses and mixings, with a minimal parameter set, predicts 1) A testable relation between the top quark mass and αₛ (MZ) which is about (1-2) σ from current best fit values, 2) The order of magnitude of the baryon asymmetry of the universe, via leptogenesis from second-generation right-handed neutrino decays. 3) The proton decay and the neutron EDM are likely observable in next generation experiments, and 4) A normal ordered neutrino mass spectrum where 0νββ decay and the mass of the lightest neutrino are out of reach of next generation experiments.
Carrasco-Martinez et al. (Wed,) studied this question.