Search for the Rare Decays Bs(d) -> MuMu

This summarizes an analysis which searches for the rare decays Bs->MuMu and Bd->MuMu. These results were blessed at the B Physics Meeting 08-Jan-2004 and correspond to a dataset of 171 pb-1. A PRL manuscript is in preparation.


The SM predicts a BR(Bs->MuMu) of about 3.8E-9, while the best limit is from CDF RunI, BR(Bs->MuMu) < 2.6E-6 @95% CL. There are various extensions to the SM predict an enhancement of this branching ratio by 1 to 3 orders of magnetude. Many of these models are, presently, theoretically very interesting since some have some relevance to the deviation of the muon (g-2), neutrino oscillations, and dark matter/dark energy results.

Here's a plot from (hep-ph/0108037), which shows BR(Bs->MuMu) in the (M_0,M_1/2) plane in the MSuGra model. The solid black lines are contours of constant BR(Bs->MuMu), the dotted green lines are contours of constant deviations of the muon (g-2) (in units of E-10) relative to SM expectations and the dash-dot red lines are contours of constant (lowest-lying) higgs mass in this model (in units of GeV). The shaded red-regions are excluded.

A second interesting class of models that predicts enhanced rates of Bs->MuMu decay are SO(10) symmetry breaking models. This plot from (hep-ph/0304101) shows BR(Bs->MuMu) in the (mu,M1/2) plane. Dashed blue lines are are contours of constant BR(Bs->MuMu), dashed black lines are are contours of constant higgs mass, green areas are regions of parameter space consistent with the observed relic density of dark matter and pink ares are excluded. This model with the choice of parameters shown in the plot is completely excluded. A listing of relevant theory papers is below.


A complete description of the analysis is available here: html, ps.


Below the eps versions of all figures available for downloads.


If you have access to internal CDFnotes, more details about the various acceptances and efficiencies can be found in these cdfnotes:

A full description of the analysis is in cdfnote 6397

The pre-blessing talk at the B Physics meeting also offers a summary of the analysis. So does a talk at the Jan-2004 collaboration meeting.

Theory Papers

Below are links the relevant theory papers: Example Feynman diagrams:

Experimental Papers

Below are links the relevant experimental papers: