Search for rare b-meson decays at CDF

We report on the search for $B_s^0\to {\mu }^{+}{\mu }^{-}$, $B_d^0\to {\mu }^{+}{\mu }^{-}$ decays and $b\to s{\mu }^{+}{\mu }^{-}$ transitions in exclusive decays of B mesons using the CDF II detector at the Fermilab Tevatron Collider. Using 2 fb${}^{-1}$ of Run II data we find upper limits on the branching fractions $\mathcal{B}(B_s^0\to {\mu }^{+}{\mu }^{-})<5.8\times {10}^{-8}$ and $\mathcal{B}(B_d^0\to {\mu }^{+}{\mu }^{-})<1.8\times {10}^{-8}$ at 95% confidence level. The results for the branching fractions of the $b\to s{\mu }^{+}{\mu }^{-}$ transitions using 924 pb${}^{-1}$ of Run II data are $\mathcal{B}(B^{+}\to {\mu }^{+}{\mu }^{-}{K}^{+})=(0.60\pm 0.15\pm 0.04)\times {10}^{-6}$, $\mathcal{B}(B_d^0\to {\mu }^{+}{\mu }^{-}{K}^{\ast 0})=(0.82\pm 0.31\pm 0.10)\times {10}^{-6}$ and $$\mathcal{B}$(B^0_s\to \mu^+\mu^-\phi)/$\mathcal{B}$(B^0_s\to J/\psi\phi) < 2.61\times 10^{-3}$ at 95% confidence level.