New observable phases in a supersymmetric extension of the standard model

Abstract

The scalar-quark--quark--gluino interaction in supergravity models with spontaneously broken local supersymmetry and complex Yukawa couplings have been examined. It is shown that while the Kobayashi-Maskawa mechanism is the only source of CP violation in these models, there are three more observable phases. These phases lead to a large neutron electric dipole moment (${10}^{\mathrm{\ensuremath{-}}25}$--${10}^{\mathrm{\ensuremath{-}}27}$ e cm) if the supersymmetric partners of quarks and gauge bosons are accessible by experiments at accelerators. It is also shown that such phases may show up by causing CP-violating ${B}_{s}$ decays where none is expected in the standard model.