Light stop decays into $W b ildeχ_1^0$ near the kinematic threshold

We investigate the decays of the light stop in scenarios with the lightest neutralino $ ilde{chi}_1^0$ being the lightest supersymmetric particle, including flavour-violating (FV) effects. We analyse the region where the three-body decay $ ilde{t}_1 o W b ilde{chi}_1^0$ is kinematically allowed and provide a proper description of the transition region between the three-body decay and the four-body decay $ ilde{t}_1 o ilde{chi}_1^0 b f ar{f}'$. The improved treatment has been implemented in the Fortran package { t SUSY-HIT} and is used for the analysis of this region. A scan over the parameter range including all relevant experimental constraints reveals that the FV two-body decay into charm and $ ilde{chi}_1^0$ can be as important as the three-, respectively, four-body decays if not dominant and therefore should be taken into account in order to complete the experimental searches for the light stop.