of $O(m_{3/2}/\kappa)$, but the fermion singlet and both scalar singlets are rather light.

Of course, the large dimension of the scalar field manifold allows for a rich structure in the overall scalar potential and leads to the existence of many local extrema [@Desa]. One has to carefully check that the phenomenologically viable vacuum is favoured with respect to the unwanted ones. Among these there are the usual $SU(3)_{c}\times U(1)_{\mathrm{em}}$ breaking ones, corresponding to vacua with quark and lepton quantum numbers [@Frere], [@Desa], [@Zwi]. In the (M+1)SSM there is the additional possibility of a non-vanishing charged Higgs field vacuum. However, the necessary condition for this particular charge violating classical solution is a relatively large coupling of the Higgses to the singlet [@Pool], so that this situation is quite naturally avoided by a bound on that coupling.Our theoretical and experimental constraints turn out to automatically selected the right region of the parameter space.

Actually, as we shall discuss here below, an acceptable minimum of the potential requires some inequalities among the soft supersymmetry breaking terms which would tend to induce $SU(3)_{c}\times U(1)_{\mathrm{em}}$ breaking vacua as well. The radiative corrections due to the gauge interactions then allow for a compromise while restricting the 