Minimal flipped $SO(10)\otimes U(1)$ supersymmetric Higgs model

We investigate the conditions on the Higgs sector that allow supersymmetric $SO(10)$ grand unified theories to break spontaneously to the standard electroweak model at the renormalizable level. If one considers Higgs representations of dimension up to the adjoint, a supersymmetric standard model vacuum requires, in most cases, the presence of nonrenormalizable operators. The active role of Planck-induced nonrenormalizable operators in the breaking of the gauge symmetry introduces a hierarchy in the mass spectrum at the grand unified theory scale that may be an issue for gauge unification and proton decay. We show that the minimal Higgs scenario that allows for a renormalizable breaking to the standard model is obtained by considering flipped $SO(10)\otimes U(1)$ with one adjoint (${45}_H$) and two pairs of ${16}_H\oplus {\overline{16}}_H$ Higgs representations. We consider a nonanomalous matter content and discuss the embedding of the model in an $E_6$ grand unified scenario just above the flipped $SO(10)$ scale.

Figure 1

Sample picture of the gauge coupling unification in the $E_6$-embedded $SO(10)\otimes U(1{)}_X$ model.