Yukawa ratio predictions in non-renormalizable SO(10) GUT models

Abstract

Abstract Since SO(10) GUTs unify all fermions of the Standard Model plus a right-chiral neutrino in a representation 16 per family, they have the potential to be maximally predictive regarding the ratios between the masses (or Yukawa couplings) of different fermion types, i.e. the up-type quarks, down-type quarks, charged leptons and neutrinos. We analyze the predictivity of classes of SO(10) (SUSY) GUT models for the fermion mass ratios, where the Yukawa couplings for each family are dominated by a single effective GUT operator of the schematic form 162 · 45n · 210m · H, for H ∈ {10,120,$$ \overline{\mathbf{126}} $$ 126 ¯ }. This extends previous works to general vacuum expectation value directions for GUT-scale VEVs and to larger Higgs representations. In addition, we show that the location of the MSSM Higgses in the space of all doublets is a crucial aspect to consider. We discuss highly predictive cases and illustrate the predictive power in toy models consisting of masses for the 3rd and 2nd fermion family.