Yukawa sector of minimal SO(10) unification

We show that in SO(10) models, a Yukawa sector consisting of a real 10(H), a real 120(H) and a complex 126(H) of Higgs fields can provide a realistic fit to all fermion masses and mixings, including the neutrino sector. Although the group theory of SO(10) demands that the 10(H) and 120(H) be real, most constructions complexify these fields and impose symmetries exterior to SO(10) to achieve predictivity. The proposed new framework with real 10(H) and real 120(H) relies only on SO(10) gauge symmetry, and yet has a limited number of Yukawa parameters. Our analysis shows that while there are restrictions on the observables, a good fit to the entire fermion spectrum can be realized. Unification of gauge couplings is achieved with an intermediate scale Pati-Salam gauge symmetry. Proton decay branching ratios are calculable, with the leading decay modes being p -> (nu) over bar pi(+) and p -> e(+) pi(0).