Tauonic B decays in the MSSM

1. Tauonic B decays in the MSSM arXiv : hep-ph/0409228 YITP : 2005.1.13 Hideo Itoh (Ibaraki univ., KEK) in collaboration with S.Komine(KEK), Y.Okada(KEK,SOKENDAI)

2. 0: Overview of the physics of the B and SuperB Factory The current experiments Asymmetric B factory experiments(1999～) KEKB(KEK) : Belle experiment (～340fb-1) PEPⅡ(SLAC) : BaBar experiment (～250fb-1) The first purpose of the B factories Precise test of the CKM picture for the CPV It succeeded! Ex.

3. The history of the integrated luminosity 2004 summer 2003 summer

4. What is the next purpose of the B factories? We look for deviation from the SM: Correction from new physics beyond the SM We need more Luminosity and far precise test. In particular: Processes of the final state including more than two neutrinos tauonic B decays : B→Dτν, B→τν To identify these processes, we have to accumlate more luminosity. Necessity of the SuperB

5. B physics LC LHC EDM LFV K physics Muon g-2 Charm physics Motivation of the SuperB Factory (Letter of Intent for KEK Super B Factory, hep-ex/0406071) SuperB Factory : Goal of the luminosity is 50-100 times more than the current achieved luminosity. ・SuperB is focused on studies for new physics (NP). ・LHC may find NP, but the information from LHC are not enough to distinguish between NP models. ・SuperB provides much information for the NP models from following measurements. - New CP phase - LFV (τ→μγ, τ→eγ,…) - Tauonic B decays - etc… These results are useful to combine with the LHC results. (Okada san)

6. KEKB Upgrade Scenario Lpeak (cm-2s-1) Lint 5x1034 1 ab-1 1.4x1034 280 fb-1 5x1035 10 ab-1 5x109 BB /year !! & alsot+t- Super-KEKB (major upgrade)

7. 1. Introduction Two types of the SUSY effects on B physics 1. For the FCNC processes (b→sγ, Bs→μμ, B→φKs…) Ex.) SUSY (loop) SM (loop) 2. For the Tauonic B decays (B→Dτν, B→τν) Ex.) SM (tree) SUSY (tree)

8. Important features of the tauonic B decays ・Charged Higgs boson can contribute to the decay amplitude at the tree level in the MSSM. ・At least two neutrinos are present in the final state in the signal side. Full-reconstruction is required for the B decay in the opposite side. It is difficult to probe the tauonic B decays. However we may probe the charged Higgs effects on the B physics if we can probe the tauonic B decays. Full-reconstruction efficiency is 10-3. So we need more and more luminosity to probe the tauonic B decays.

9. SM prediction and current experimental results The branching ratio of the tauonic B decays at the SM ・B→Dτν : 8×10-3 ・B→τν : 9×10-5 ・B→Dτνis larger branching ratio. There is no experimental data. We have not probed B→Dτνat both B factories. ・B→τνis smaller branching ratio due to helicity suppression. Experimental data - Upper bound from Belle : 2.9×10-4 - Upper bound from BaBar : 3.3×10-4 These processes are important target of the SuperB Factory.

10. Also there are SUSY corrections to the Yukawa couplings SUSY correction to yd is induced due to 1-loop diagrams. (K.S.Babu & C.Kolda, M.Carena, et al) Contributing diagrams SUSY corrections The b→c(u)τυ processes in the MSSM

11. This correction affects the branching ratios for some other processes too. Ex. BS→μμ(A.Dedes & Pilaftsis, et al) b→sγ (G.Degrassi & P.Gambino & G.F.Giudice, et al) … We study B￫Dτνand B￫τν in MSSM ・Assume the Minimal Flavor Violation case Explain later・・・ ・SUSY correction to H±-c (u )-b and H±-τ-νvertex ・Correlation between b￫sγ, Bs￫μ+μ- and tauonic B decays.

12. Different types of the tree level Yukawa couplings are induced by SUSY effects through 1-loop diagram. (A.Dedes & A.Pilaftsis) 2: Formalism Tree level Yukawa couplings have the same structure as that of the superpotential. Framework: MSSM with MFV and large tanβ

13. MSSM with Minimal Flavor Violation (MFV) Minimal Flavor Violation Squarks have the same flavor structure as one of the quarks. In other words, the flavor changing source is only the KM matrix. ・Not MFV case The large deviation from SM is possible generally. Because there are many flavor mixing parameters. ・MFV case The large deviation from SM is possible for large tanβ. tanβ is the ratio of the two vacuum expectation values of the neutral Higgs. This assumption comes from mSUGRA, GMSB, AMSB ・・・.

14. Under the Minimal Flavor Violation

15. Under the Minimal Flavor Violation Loop function

16. The SUSY corrections at b→u,c are given by SUSY corrections to the charged Higgs couplings Charged Higgs coupling including SUSY correction : (“ “ denotes a diagonal matrix.) For the correction to the down-type Yukawa coupling

17. In Minimal Flavor Violation case ・gluino-sbottom contribution ・higgsino-stop contribution at MFV Higgsino contribution becomes too small in comparison with gluino contribution. For the correction to the lepton Yukawa coupling

18. These SUSY corrections appear via the following combina -tion of the parameters in the branching ratio formulas. SUSY effects are absorbed into the value of tanβ. I will explain later. If there are no SUSY corrections (Ex. 2HDM case)

19. In MFV case SUSY 2HDM Intuitively, these SUSY corrections become the vertex correction like below. Also we can see the following results. B→Dτν B→τν There is a correlation between the tauonic B decays at MFV!

20. SUSY parameters for the tauonic B decays at MFV ・Tree-level charged Higgs effect depends on the following parameters. ・The SUSY corrections to the Yukawa couplings depend on the follow -ing parameters with tanβ.

21. 3: Numerical results The SUSY correction matrix elements

22. 3: Numerical results The SUSY correction matrix elements At above parameter space, the SUSY correction to the lepton Yukawa coupling becomes sizable in comparison with the down-type Yukawa’s one.

23. μ = -400GeV μ = 400GeV μ = -400GeV μ = 400GeV No SUSY cor. case SM SM No SUSY correction case Branching ratio for B￫Dτν and B￫τν at tanβ = 50 B￫Dτν B￫τν μ is the higgsino mass parameter. The SUSY corrections drastically contribute to the branching ratio.

24. Theoretical uncertainties : ・Vertical error : 25 ・Horizontal error : ・SuperKEKB : 5ab-1 Sensitivity to reach to 11 SM 5 20 10 15 The correlation itself is the same as the 2HDM, and so one cannot distinguish them. The correlation of the two processes as a function of In MFV, SUSY effect can be absorbed into an effective tanβ. It is thus interesting to compare it with other experiments.

25. Au=Ad=-100GeV no SUSY corr. Au=Ad=100GeV Au=Ad=-100GeV no SUSY corr. Au=Ad=100GeV Effect on other process: b￫sγ Au and Ad are trilinear scalar couplings ・Charged Higgs and chargino-stop diagrams contribute. ・For μ<0 case, fine-tuning of parameters is necessary.

26. Au=Ad=-100GeV Upper bound from exp. Au=Ad=-100GeV Upper bound from exp. Au=Ad=100GeV Au=Ad=100GeV Effect on other process: Bs￫μ+μ- ・SM prediction : 3.4×10-9 ・Receive the large SUSY corrections ・μ<0 case is strongly restricted by b￫sγ

27. 4. Summary Receive large correction via SUSY loops. MSSM with MFV at large tanβ : B￫Dτνand B￫τν The correlation between Br[B￫Dτν] and Br[B￫τν] in MFV SUSY loop effect absorbed into the effective tanβ Correlation is same as the 2HDM Important to compare : measurements of Br[B￫Dτν] and Br[B￫τν] (SuperB Factory ) : measurements of tanβ (LHC ) Ex. ・heavy Higgs direct production ・chargino/neutralino mixing ・stau decay b￫sγ and Bs￫μ+μ- :receive large correction generally in the same parameter space