Search for the rare decays B+-->mu+mu-K+, B-->mu+mu-K*(892), and Bs-->mu+mu- phi at CDF

Abstract

We search for b→sμ[superscript +]μ[superscript -] transitions in B meson (B[superscript +], B[superscript 0], or B[subscript s][superscript 0]) decays with 924 pb[superscript -1] of pp[over -bar] collisions at sqrt [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[superscript +]→μ[superscript +]μ[superscript -]K[superscript +], B[superscript 0]→μ[superscript +]μ[superscript -]K*(892)[superscript 0], and B[subscript s][superscript 0]→μ[superscript +]μ[superscript -]ϕ decay modes, respectively. Using B→J/ψh (h=K[superscript +], K*(892)[superscript 0], ϕ) decays as normalization channels, we report branching fractions for the previously observed B[superscript +] and B[superscript 0] decays, B(B[superscript +]→μ[superscript +]μ[superscript -]K[superscript +])=(0.59±0.15±0.04)×10[superscript -6], and B(B[superscript 0]→μ[superscript +]μ[superscript -]K*(892)[superscript 0])=(0.81±0.30±0.10)×10[superscript -6], where the first uncertainty is statistical, and the second is systematic. We set an upper limit on the relative branching fraction B(B[subscript s][superscript 0]→μ[superscript +]μ[superscript -]ϕ)/B(B[subscript s][superscript 0]→J/ψϕ)<2.6(2.3)×10[superscript -3] at the 95(90)% confidence level, which is the most stringent to date.