Light Stop Decays

If the stop is the next-to-lightest supersymmetric particle (NLSP) and the mass difference to the neutralino is smaller than the top mass, it can decay via flavour-violating decay modes to $c{\tilde{\chi }}_1^0\mathrm{/}u{\tilde{\chi }}_1^0$ or a four-body decay to $b{\tilde{\chi }}_1^{0}f{\bar{f}}^{\mathrm{\prime }}$, which above the $W$ boson threshold corresponds to the decay to $b{\tilde{\chi }}_1^{0}W$. Improving on existing calculations for these decay modes, we analyse the branching ratios (BRs) for the respective decays and show that they can significantly deviate from one.