1301.7048 (CDF Collaboration)
CDF Collaboration
We report on a search for \bsmm\ and \bdmm\ decays using proton-antiproton collision data at $\sqrt{s}=1.96$~TeV corresponding to $10~\fb$ of integrated luminosity collected by the CDF detector at the Fermilab Tevatron collider. The observed number of \bd\ candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of $\brbdmm < 4.6\times 10^{-9}$ at 95\% confidence level. We observe an excess of \bs\ candidates. The probability that the background processes alone could produce such an excess or larger is $0.94\%$. The probability that the combination of background and the expected standard model rate of \bsmm\ could produce such an excess or larger is $6.8\%$. These data are used to determine a branching fraction $\brbsmm = (1.3^{+0.9}_{-0.7}) \times 10^{-8} $ and provide an upper limit of $\brbsmm < 3.1\times 10^{-8}$ at 95\% confidence level.
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http://arxiv.org/abs/1301.7048
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