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...
In models with extended scalar sectors that include multiple Higgs doublets responsible for spontaneous electroweak symmetry breaking, it may appear that the numerous dimensionful quadratic terms in the scalar potential could support a scenario where, aside from the would-be Goldstone bosons and a neutral Higgs-like particle, all additional scalars acquire masses well above the electroweak...
Although, a fourth chiral generation of fermions is excluded by experimental data, the possibility of extending the SM with vector-like quarks, where both chiral components transform the same way under SU(2)_L, has not been ruled out. In fact, these fields are present in a great variety of NP models, from GUTs to solutions to the strong CP problem.
Moreover, introducing VLQs leads to the loss...
