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
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
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
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:
Below the eps versions of all figures available for downloads.
- Figure 1 : shape comparison between Signal and Background for discriminating variables
- Figure 2 : correlation plots for background
- Figure 3 : background invariant mass distribution
- Figure 4 : comparison of mu+mu- pairs with ctau>0 and ctau<0
- Figure 5 : the
invariant mass distribution of events passing all cuts in 171 pb-1
- Figure 6 : expected 90% CL upper limit BR(Bs->MuMu) vs CDF integrated luminosity
- Figure 7 : CDF Bs->MuMu single event sensitivity vs integrated luminosity. The Bd->MuMu single event sensitivity is about four times smaller.
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.
Below are links the relevant theory papers:
Example Feynman diagrams:
- hep-ph/0108037 Correlation of Bs -> mu+mu- and (g-2)mu in Minimal Supergravity
- hep-ph/0207026 Trilepton Events and Bs -> mu+mu- : No-lose for mSUGRA at the Tevatron?
- hep-ph/0203069 Detection of Bs->mu mu at the Tevatron Run II and Constraints on the SUSY Parameter Space
- hep-ph/0205325 Updated Constraints on the Minimal Supergravity Model
- hep-ph/0310042 Bs -> mumu as a Probe of Tan(beta) at the Tevatron
- hep-ph/0304101 Dark Matter And Bs to mu+mu- With Minimal SO(10) Soft SUSY Breaking
- hep-ph/0302155 Yukawa Coupling Unification in Supersymmetric Models
- hep-ph/0104284 Analysis of Neutral Higgs-Boson Contributions to the Decays Bs -> l+l- and B -> Kl+l-
- hep-ph/0207241 Correlation between Delta Ms and B0s,d -> mu+mu- in Supersymmetry at Large tan beta
- Standard Model diagrams: Box and Penguin
- 2HDM diagrams: Box and Penguin
- SUSY diagrams: Loop
- Higgs mediated: Tree - where multiple Higgs can allow flavor violating diagrams
- R-Parity violating: Tree
Below are links the relevant experimental papers: