Search for the rare decays B+→μ+μ-K+, B0→μ+μ-K*(892)0, and Bs0→μ+μ-ϕ at CDF

We search for b→sμ+μ- transitions in B meson (B+, B0, or Bs0) decays with 924  pb-1 of pp̅ collisions at √s=1.96  TeV collected with the CDF II detector at the Fermilab Tevatron. We find excesses with significances of 4.5, 2.9, and 2.4 standard deviations in the B+→μ+μ-K+, B0→μ+μ-K*(892)0, and Bs0→μ+μ-ϕ decay modes, respectively. Using B→J/ψh (h=K+, K*(892)0, ϕ) decays as normalization channels, we report branching fractions for the previously observed B+ and B0 decays, B(B+→μ+μ-K+)=(0.59±0.15±0.04)×10-6, and B(B0→μ+μ-K*(892)0)=(0.81±0.30±0.10)×10-6, where the first uncertainty is statistical, and the second is systematic. We set an upper limit on the relative branching fraction B(Bs0→μ+μ-ϕ)/B(Bs0→J/ψϕ)<2.6(2.3)×10-3 at the 95(90)% confidence level, which is the most stringent to date.