Spontaneous CP Violation and Flavor Changing Neutral Currents in Minimal SO(10)

Abstract

We explore spontaneous CP violation (SCPV) in the minimal non-supersymmetric SO(10) grand unified theory (GUT), with a scalar sector comprising a CP-even $45_H$, a $126_H$, and a complex $10_H$. All renormalizable couplings are real due to CP symmetry, and the Kobayashi-Maskawa phase arises solely from complex electroweak vacuum expectation values. The model requires an additional Higgs doublet fine-tuned below 500 GeV and constrains new Yukawa couplings, linking certain flavor-violating (FV) processes. Future proton decay observations may reveal correlated FV decay ratios, offering insights into minimal SO(10).

Comments: 24 pages, 4 figures; version published in PRD