Fermion Masses and Mixings in a Minimal SO(10)X A_4 SUSY GUT

Understand

A SUSY SO(10) $\times A_4$ GUT model is constructed for fermion masses and mixing by introducing a minimal set of low dimensional Higgs representations needed to break the guage symmetry down to $SU(3)_c \times U(1)_{em}$.

• The hierarchy of fermion masses can be understood in the framework of $A_4$ symmetry.
• From the $A_4$-invariant superpotential, the "double lopsided" mass matrices for the charged leptons and the down quarks are obtained.
• It is shown that this structure leads to bi-large neutrino mixings simultaneously with small CKM mixing angles.