Bajc-Melfo vacua enable Yukawon ultraminimal grand unified theories

Abstract

Bajc-Melfo (BM) two-field (S,ϕ) superpotentials define metastable F-term supersymmetry-breaking vacua suitable as hidden sectors for calculable and realistic family and grand unification models. The undetermined vacuum expectation value (VEV) ⟨Ss⟩ of the Polonyi field that breaks supersymmetry can be fixed either by coupling to N=1 supergravity or by radiative corrections. BM hidden sectors extend to symmetric multiplets (S,ϕ)ab of a gauged O(Ng) family symmetry, broken at the GUT scale, so that the O(Ng) charged component VEVs ⟨^Sab⟩ are also undetermined before accounting for the O(Ng) D-terms, which fix them by cancellation against D-term contributions from the visible sector. This facilitates Yukawon ultraminimal GUTs (YUMGUTs) proposed in [C. S. Aulakh and C. K. Khosa, Phys. Rev. D 90, 045008 (2014)] by relieving the visible sector from the need to give null D-terms for the family symmetry O(Ng). We analyze symmetry breaking and spectra of the hidden-sector fields in the supergravity resolved case when Ng=1,2,3. Besides the Polonyi field Ss, most of the superfields ^Sab remain light, with fermions getting masses only from loop corrections. Such modes may yield novel dark matter lighter than 100 GeV. Possible Polonyi and moduli problems associated with the fields Sab call for detailed investigation of loop effects due to the Yukawa and gauge interactions in the hidden sector and of postinflationary field relaxation dynamics.