Constraints from the decay Bₛ -> mu mu and LHC limits on Supersymmetry

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The pure leptonic decay Bₛ -> mu mu is strongly suppressed in the Standard Model (SM), but can have large enhancements in Supersymmetry, especially at large values of tanbe. New limits on this decay channel from recent LHC data have been used to claim that these limits restrict the SUSY parameter space even more than the direct searches. However, direct searches are hardly dependent on tanbe, while BR(Bₛ -> mu mu) is proportional to tanbe⁶. The relic density constraint requires large tanbe in a large region of the parameter space, which can lead to large values of Bₛ -> mu mu. Nevertheless, the experimental upper limit on BR(Bₛ -> mu mu) is not constraining the parameter space of the CMSSM more than the direct searches and the present Higgs limits, if combined with the relic density. We also observe SUSY parameter regions with negative interferences, where the Bₛ -> mu mu value is up to a factor three below the SM expectation, even at large values of tanbe.