Tauonic B decay
in a supersymmetric model
YITP workshop:Progress in Particle Physics 2004.6.30
Hideo Itoh (KEK, Ibaraki univ.)
in collaboration with
S.Komine(KEK), Y.Okada(KEK)
1: Introduction
We want to probe the evidence of new physics
Many candidates beyond the SM
2HDM, SUSY, GUT…
Including two Higgs doublet
If we can probe charged Higgs effects on B physics
Indirect signal of the new physics
We can probe charged Higgs effect in the
(M.Tanaka:1994, J.A.Coarasa, R.A.Jimenez, J.Sora:1997,
G.H.Wu, K.Kiers, J.N.Ng:1997 …)
Contributing diagram
Charged Higgs provide large contribution
Also, if we consider a supersymmetric model
Appear the SUSY corrections for Yukawa sector
After EW symmetry breaking
It becomes mass correction for the bottom quark mass
(K.S.Babu & C.Kolda, M.Carena, et al)
This affects branching ratios for some processes!
(ex. BS→μμ , etc …)
We also include additional tau mass corr.
We estimated these effects for the following two processes
B￫Dτν
and
B￫τν
We will probe the super B factory
Super B factory: The luminosity is 50-100 times more than
the current achieved luminosity.
In this talk
We will show the following contents
SUSY corrections for B￫Dτν and B￫τν
in our framework.
Numerical results and Conclusions.
Summary.
2: Formalism
(A.Dedes & A.Pilaftsis)
Our framework: MSSM with MFV and large tanβ
Tree level Yukawa coupling have the same structure
of the superpotential.
Different type of the tree level Yukawa couplings
are induced SUSY effects through 1-loop diagram.
are 1-loop induced coupling constant
1-loop diagram for
1-loop diagram for
Our calculating flow
1:Assumed MFV
2:Calculated the gluino and charged higgsino
and bino diagrams.
3:Estimated mass matrices that including SUSY
corrections.
4:Diagonalized mass matrices.
5:Derived charged Higgs couplings.
1:
Results
negligible
2:higgsino cont. is suppressed by
negligible
Charged Higgs couplings
Contribution of the loop diagrams
Therefore, 4-Fermi effective Lagrangian
for B￫Dτυ process
Hadronic matrix elements for
Decay amplitude
Differential partial width for
Therefore, 4-Fermi effective Lagrangian
for B￫τυ process
Hadronic matrix elements for
Decay width
3: Numerical results
For correction matrices
We estimated the correction matrices against
several value of the SUSY parameter.
There is parameter region that tau mass correction
becomes comparable with the bottom mass correction.
So if we estimate the branching ratio without tau mass
correction, we mislead the results.
For correction matrices
μ=400GeV
μ=-400GeV
3: Numerical results
In B￫Dτν process
For branching ratio
No experimental data
SM prediction: Br～8×10-3
Super B factory
5ab-1 : 7.9%
50ab-1: 2.5%
} Expected uncertainties in the measured Br.
Branching ratio for B￫Dτν
tanβ=50
tanβ=30
SUSY cor. case at μ = -400GeV
SM pred.
SUSY cor. case at μ = 400GeV
No SUSY cor. case
SM pred.
SUSY cor. case at μ = 400GeV
No SUSY cor. case
SUSY cor. case at μ = -400GeV
Form factor is canceled by taking ratio B￫Dτν and B￫τν.
Theoritical uncertainty becomes small.
We can see that loop correction affects for tree diagram
drasticaly.
In B￫τν process
SM prediction: Br = 0.9×10-4
From BaBar : Br < 4.1×10-4
Super B factory will be sensitive to SM rates
Expected 4σ significance at 2 ab-1
Decay constant :
Branching ratio for B￫τν
tanβ=30
tanβ=50
SUSY cor. case at μ = -400GeV
No SUSY cor. case
SUSY cor. case at μ = -400GeV
SUSY cor. case at μ = 400GeV
SM pred.
SM pred.
No SUSY cor. case
SUSY cor. case at μ = 400GeV
We can see that loop correction affects for tree diagram
drastically too.
We show the correlation between these two processes
μ= - 400GeV
μ= 400GeV
We choose the charged Higgs mass as variable, 150～400GeV.
Since we assumed MFV, these correlation appears.
It is important to investigate the both processes.
Contour plot for several cases for B￫Dτν
No SUSY corr.
lowest -40% -30% -20%
-10%
SM pred.
μ=400GeV
-40%
-30% -20%
μ=-400GeV
lowest
-10%
-40%
-30%
-20%
-10%
SM pred.
SM pred.
Contour plot for several cases for B￫τν
No SUSY corr.
Exp. bound
lowest
}
μ=400GeV
lowest
-90%
-10%
SM pred.
10%
20%
30%
μ=-400GeV
-80%
-70%
-60%
-50%
-40%
-30%
Exp.bound
200%
SM pred.
-90%
lowest
4:Summary
The B￫Dτυ and B￫τυ processes on the MSSM that
assumed MFV and large tanβ.
SUSY corrections for the bottom and the tau mass.
SUSY loop correction is very large.
and
There is parameter region where corrections
due to tau mass and bottom mass become
comparable.
So tau mass correction is important.

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