Speaker
Description
We examine how large the effects in $b\to s\ell^+\ell^-$ transitions in the MSSM with a general flavour structure can be. After carefully analyzing all potentially important supersymmetric contributions, we find that the largest effects arise in case of a light wino, a light smuon and muon sneutrino, a relatively light left stop, maximal mixing among left-handed down-squarks of the $2^{\rm nd}$ and $3^{\rm rd}$ generation, with one light (order 600 GeV) and one decoupled mass eigenstate. While the bound from $B\to X_s \gamma$ can always be avoided by a suitable choice of flavour violating $A$ terms or large $\mu$-term, $B_s-\bar B_s$ mixing depends mainly (for fixed squark and Wino masses) on the gluino and the Bino mass. However, also in the latter observable, a cancellation, because of the crossed gluino diagrams, is possible. We find that the effect in $R(K)$ and $R(K^*)$ can be at most of the order of 5\% and correlate this to SUSY searches at the LHC. Concerning the LFU observables where still tensions with the SM predictions exist, like $P_5^\prime$ and the total branching ratios of $B_s\to\phi\mu\mu$ and $B\to K\mu\mu$, only even smaller are possible, due to an unavoidable cancellation between the Wino box diagram and the respective off-shell photon penguin.
