A Combination of CDF and DO Limits on the Branching Ratio of B_s(d) to mu+ mu- Decays

TL;DR

This paper combines results from CDF and D0 experiments to set the most stringent limits to date on the rare decay branching ratios of B_s and B_d mesons to mu+ mu-, using data normalization and fragmentation ratios.

Contribution

It presents a combined analysis of CDF and D0 data to improve limits on B_s and B_d to mu+ mu- decay branching ratios, the most stringent to date.

Findings

BR(B_s to mu+ mu-) > 1.5x10^-7 at 95% CL

BR(B_d to mu+ mu-) > 4.0x10^-8 at 95% CL

Most stringent limits on these decays so far

Abstract

We combine the results of CDF and DO searches for the rare decays B_s to mu+ mu- and B_d to mu+ mu-. The experiments use 364 pb-1 and 300 pb-1 of data respectively. The limits on the branching ratios are obtained by normalizing the estimated sensitivity to the decay B+ to J/psi K+, taking into account the fragmentation ratios f_u/f_s(d). The combined results exclude branching ratios of BR(B_s to mu+ mu-) > 1.5x10-7 and BR(B_d to mu+ mu- > 4.0x10-8 at 95% confidence level. These are the most stringent limits on these decays at the present time.