Search for Bs0→μ+μ- and B0→μ+μ- decays with the full CDF Run II data set

Abstract

We report on a search for Bs0→μ+μ- and B0→μ+μ- decays using proton-antiproton collision data at √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 B0 candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of B(B0→μ+μ-)<4.6×10-9 at 95% confidence level. We observe an excess of Bs0 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 Bs0→μ+μ- could produce such an excess or larger is 6.8%. These data are used to determine a branching fraction B(Bs0→μ+μ-)=(1.3-0.7+0.9) ×10-8 and provide an upper limit of B(Bs0→μ +μ-)<3.1×10-8 at 95% confidence level. © 2013 American Physical Society.