SpontaneousCPviolation in the supersymmetric Higgs sector

Spontaneous CP violation in the minimal supersymmetric standard model with a gauge singlet and a cubic superpotential is examined. Although the tree-level Higgs potential conserves CP, it is shown that with the inclusion of the one-loop top-quark radiative effects CP may be broken spontaneously. The CP-violating minimum requires two neutral (${\mathit{h}}_1$,${\mathit{h}}_2$) and one charged (${\mathit{H}}^{\pm }$) Higgs boson to be relatively light with ${\mathit{m}}_{\mathit{h}1}$+${\mathit{m}}_{\mathit{h}2}$≲100 GeV and ${\mathit{m}}_{\mathit{H}}^{\pm }$≲110 GeV. The electric dipole moment of the electron is in the observable range of (1/3 to 3)×${10}^{\mathrm{-}27}$e cm.