approximately obtained from the third equation in (\[I\]) with $h_2=h_1=0$,

$$s \simeq \frac{-A_{\kappa }-\sqrt{A_{\kappa }^{2}-8m_{S}^{2}}}{4\kappa }
 \label{O}$$

The potential at this value of $s$ has also to be negative in the allowed region of the parameter space, as discussed in more detail in section \[sec:stability\]. This additional condition requires $$9m_{S}^{2}<A_{\kappa }^{2}
\label{neccon}$$ This approximation turns out to be very accurate. The parameters $A_{\kappa} $ and $m_{S}^{2}$ are only slightly renormalized if $\kappa ,\lambda \ll 1. $ Actually, these relatively low values of the couplings are also required by our numerical study of the model, so that the condition (\[neccon\]) approximately applies to the bare universal parameters $A_{0},m_{0}^{2},$ yielding the strong constraint in the parameter space: $$A_{0}^{2} \gtrsim 9m_{0}^{2}
\label{neccon1}$$

The $S$ v.e.v. in (\[O\]) defines the effective parameters $\hat{B}$ and $\hat{\mu}$ analogous to those often denoted $B$ and $\mu $ in the MSSM. Indeed, up to corrections of $O\left( h_{2}^{2}/s^{2}\right) ,$ the first two equations in (\[I\]) are the same as in the MSSM with the introduction of these parameters. Notice that $\hat{\mu}\sim \lambda A_{\kappa }/2\kappa$ should be of $O\left( m_{3/2}\right) .$ Hence the well–known “fine-tuning” on the MSSM free parameter, $\mu \sim O\left( m_{3/2}\right) ,$ is replaced here by 