Complete one--loop analysis to stop and sbottom decays into $Z$ and $W^{\pm}$ bosons

We study radiative correctionsto third generation scalar fermions into gauge bosons$Z$ and $W^\pm$. We include both SUSY-QCD, QED and full electroweak corrections. It is found that the electroweak correctionscan be of the same order as the SUSY-QCD correctionsand interfere destructively in some region of parameter space. The full one loop correctioncan reach 10% in some SUGRA scenario, while in general MSSM, the one loop correctioncan reach 20% for large $\tan\beta$ and large trilinear soft breaking terms $A_b$.