Approximate CP in Supersymmetric Models

Abstract

We construct phenomenologically viable supersymmetric models where CP is an approximate symmetry. The full high energy theory has exact CP and horizontal symmetries that are spontaneously broken with a naturally induced hierarchy of scales, $\Lambda_{CP}\ll\Lambda_H$. Consequently, the effective low energy theory, that is the supersymmetric Standard Model, has CP broken explicitly but by a small parameter. The $\epsilon_K$ parameter is accounted for by supersymmetric contributions. The predictions for other CP violating observables are very different from the Standard Model. In particular, CP violating effects in neutral B decays into final CP eigenstates such as $B\ra\psi K_S$ and in $K\ra\pi\nu\bar\nu$ decays are very small.