^{2}}\;STr\;m^{4} \ln \frac{m^{2}}{%
Q^{2}}  \label{G}$$

The appropriate mass terms in (\[G\]) are then the top quark mass $m_t^2$ and the stop masses

$$\begin{aligned}
m_{T_{1,2}}^{2} &=&m_{t}^{2}+\frac{1}{2}\left(
m_{Q_{3}}^{2}+m_{T}^{2}\right) \pm W, \mathrm{where}  \nonumber \\
W^{2} &=&\frac{1}{4}\left( m_{Q_{3}}^{2}+m_{T}^{2}\right) +h_{t}^{2}\left|
A_{t}h_{2}+\lambda sh_{1}\right| ^{2},  \nonumber \\
m_{t} &=&h_{t}h_{2}.  \label{H}\end{aligned}$$

All the parameters in (\[F\]) and (\[G\]) are to be taken at the scale $%
Q^{2}\sim O\left( h_{1}^{2}+h_{2}^{2}\right) .$

These radiative corrections are mostly due to the splitting between the quarks and the squarks. However, even if one starts from universal parameters at $\Lambda_{\mathrm{GUT}},$ the RGE running introduce some asymmetry in the stop sector as can be seen from the formulae in the Appendix. The resulting splitting in $m_{T_{1}}^{2}-m_{T_{2}}^{2}$ produces a sizeable effect in $V_{%
\mathrm{rad}}$ and in the scalar mass spectrum. The full one loop expressions for the mass matrices and the potential minimization are available in the literature. All the numerical calculations in the present paper are performed by using the formulae in [@Elrc]. However, for the sake of the analytic approximations discussed below we use a simple approximation by keeping only the lowest relevant order in the development in terms of the stop splitting, $\left( m_{T_1}^2-m_{T_2}^2\right) /\left( m_{T_1}^2+m_{T_2}^2\right) .$ The minimization of the scalar 