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Investigating Lepton Flavor Violation in Tau Decays: Higgs-Mediated Effects and Implications

This seminar explores the phenomenon of lepton flavor violation (LFV) in tau decays, focusing on Higgs-mediated interactions. We discuss the implications of LFV, particularly in the context of new physics beyond the Standard Model. The presentation highlights theoretical frameworks, including the seesaw mechanism and the role of supersymmetry (SUSY), in generating nonzero neutrino masses and possible flavor violations. Additionally, it reviews experimental prospects at B-factories and future facilities for probing LFV in tau decays, drawing on insights from recent research and CP violation studies.

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Investigating Lepton Flavor Violation in Tau Decays: Higgs-Mediated Effects and Implications

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  1. Lepton flavor violation in Tau decays Chuan-Hung Chen Department of Physics, National Cheng-Kung U., Tainan, Taiwan seminar@cycu.11.21.06.tw Introduction & Motivation Higgs-mediated LFV Implications of LFV in tau decays Speculation of Higgs-mediated effects

  2. Introduction & Motivation What we can learn from B factories: • CP violations: time-dependence CP asymmetry & direct CP violation ICHEP2006: 1 with bs Penguins

  3. Test QCD theories: PQCD, QCDF, final state interactions etc. • Determine the parameters of CKM matrix elements, or fB

  4. Probe flavor structures:

  5. B-factory: 1 ×109 t Super-B: 100 ×109 t CLEO-c: 10 ×106 t BES-III: 100 ×106t Future tau () physics

  6. results up to 2005

  7. Lepton flavor violation (LFV) • quark flavor changing via charged current; charged weak current is written as In terms of physical eigenstates By Wolfenstein parametrization

  8. In the standard model (SM), the flavor changing neutral currents (FCNCs) arise from loop • Rear decays induced from loop will be sensitive to new physics. • In the SM, since neutrinos are massless, there are no flavor violations in lepton sector • According to observed neutrino oscillations, we know that neutrinos have masses so that Maki-Nakagawa-Suzuki-Pontecorvo (MNSP)

  9. Higgs-mediated LFV • Nonzero neutrino masses are definite. • It is found that seesaw mechanism, by introducing singlet right-handed Majorana neutrinos, is one of natural ways to solve the tiny neutrino masses which are less than a few eV. • In non-SUSY models, the effects of LFV are suppressed by 1/MR which is around GUTs scale 1015 GeV. • However, in models with SUSY, due to the right-handed Majorana introduced, the flavor conservation in the slepton sector at unified scale will be violated at the MR scale via renormalization. Borzumati, Masiero, PRL57,961; Hall, Rattazzi, Sarid, PRD50,7048;Babu, Kolda, PRL89,241802

  10. Babu & Kolda’s mechanism for lepton flavor violation nonholomophic terms

  11. At large tan ~ mt/mb, or cos << 1, the Higgs-mediated LFV will be enhanced

  12. Implications of LFV in  decays   (, 3, , KK) induced by slepton mixings with large tan Due to slepton mixings

  13. Due to nonholomophic effects, is not diagonal matrix LFV with Higgs-mediated nonholomophic terms Y: diagonalized Yukawa matrix of leptons • Since 2 are loop effects, they are much less than 1, the LFV can be regarded as a leading expansion of 2Iij

  14. Employ the physical mass eigenstates of the Higgses • The interactions for the LFV via the Higgs-mediated mechanism • are expressed by

  15. Since the LFVs in and decay are driving by the same mechanism, to simplify the discussions, we take M1~M2~m0~~    • MU ~ 1019 GeV , MR ~ 1014 GeV • tan=60 • BR< (3.1, 0.68)  107

  16. s  A , ’  s • =39.30 • fs=0.17 GeV • mss=0.69 GeV

  17.  s h, H  s •  = 300, • ms = 0.15 GeV, • decoupling limit:  /2

  18.  A h, H   • cs: cos(-)sin  ; sc=sin(-)cos • decoupling limit:  /2

  19.  K h, H  K • v=2.87 GeV, =-10.4 GeV4 Cheng,Chua, Soni, PRD72,094003

  20. Speculation of Higgs-mediated effects • In terms of squark mixings, Babu,Kolda, PRL84,228(00)

  21. It is interesting to examine the effects on B decays • Charged Higgs on B • Higgs-mediated on • Higgs-mediated on • Higgs-mediated on

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