Minimal Flipped SO(10) x U(1) Supersymmetric Higgs Model

We investigate the conditions on the Higgs sector that allow supersymmetric SO(10) grand unified theories (GUT) to break spontaneously to the standard electroweak model (SM) 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 non-renormalizable (NR) operators. The active role of Planck induced NR operators in the breaking of the gauge symmetry introduces a hierarchy in the mass spectrum at the GUT 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 SM is obtained by considering flipped $SO(10) \otimes U(1)$ with one adjoint ($45_H$) and two pairs of $16_H \oplus \bar{16}_H$ Higgs representations. We consider a non-anomalous matter content and discuss the embedding of the model in an $E_6$ grand unified scenario just above the flipped SO(10) scale.