Gauged SO(3) family symmetry and squark mass degeneracy

Abstract

It is shown that a gauged SO(3) family symmetry can suppress flavor-changing processes from squark-mass non-degeneracy to an acceptable level. The potentially dangerous SO(3) D-terms can be rendered harmless if the CP-violating phases appearing in the SO(3)-breaking sector are small, which can naturally be the case if CP is a spontaneously broken symmetry. This approach has certain advantages over models based on global or non-abelian discrete symmetries, and dovetails with some recent proposals for explaining the pattern of quark and lepton masses. Moreover this approach relates the near-degeneracy of the squark masses to an approximate CP invariance which can also explain the smallness of the electron and neutron electric dipole moments.