Search for B-s(0) -> mu+ mu(-) and B-0 -> mu+ mu(-) decays with the full CDF Run II data set

We report on a search for B-s(0) -> mu(+)mu(-) and B-0 -> mu(+)mu(-) decays using proton-antiproton collision data at root s = 1.96 TeV corresponding to 10 fb(-1) of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B-0 candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of B(B-0 -> mu(+)mu(-)) < 4.6 x 10(-9) at 95% confidence level. We observe an excess of B-s(0) 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 B-s(0) -> mu(+)mu(-) could produce such an excess or larger is 6.8%. These data are used to determine a branching fraction B(B-s(0) -> mu(+)mu(-)) = (1.3(-0.7)(+0.9) x 10(-8) and provide an upper limit of B(B-s(0) -> mu(+)mu(-)) < 3.1 x 10(-8) at 95% confidence level. DOI: 10.1103/PhysRevD.87.072003