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Zee Model with a Flavor Dependent Global U(1) Symmetry

Zee Model with a Flavor Dependent Global U(1) Symmetry. Kei Yagyu Osaka U. Collaboration with Takaaki Nomura (KIAS). 1905.XXXXX [hep- ph ]. 2019, May. 27 th , 7 th RISE Collaboration Workshop. Neutrinos as the Evidence of BSM.

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Zee Model with a Flavor Dependent Global U(1) Symmetry

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  1. Zee Model with a Flavor Dependent Global U(1) Symmetry Kei Yagyu Osaka U. Collaboration with Takaaki Nomura (KIAS) 1905.XXXXX [hep-ph] 2019,May.27th, 7th RISE Collaboration Workshop

  2. Neutrinos as the Evidence of BSM • Neutrino physics shows the clear evidence of BSM, and it is still mysterious. ・What is the origin of tiny neutrino masses? ・Are neutrinos Majorana or Dirac particles? τ,c,b μ t e E ・Which are the correct mass hierarchy, Normal or Inverted? keV MeV GeV eV ・Does the neutrino sector contain CP-violation? http://www.hyper-k.org

  3. Neutrinos as the Evidence of BSM • Neutrino physics shows the clear evidence of BSM, and it is still mysterious. ・What is the origin of tiny neutrino masses? ・Are neutrinos Majorana or Dirac particles? τ,c,b μ t e E ・Which are the correct mass hierarchy, Normal or Inverted? keV MeV GeV eV ・Does the neutrino sector contain CP-violation? Inmytalk, ... http://www.hyper-k.org

  4. Neutrino Mass Generations Weinberg (1979) • Majorana neutrino masses are described by a dimension 5 operator v v Φ Φ ν ν ν ν L L L L • From ν experiments, mν should be O(0.1) eV. M ~ O(1015) GeV if C ~ 1. Eg., C ~ O(10-8)if M ~ v.

  5. Renormalizable Models Mikowski (1977), Yanagida, Gell-Mann (1979) Mohapatra, Senjanovic (1980) • The type-I seesaw mechanism y y ν ν ν • Radiative seesaw mechanism L L R Usually, more suppressions like (ml/v)p can appear depending on a model. Loop structure

  6. Renormalizable Models Mikowski (1977), Yanagida, Gell-Mann (1979) Mohapatra, Senjanovic (1980) • The type-I seesaw mechanism y y ν ν ν • Radiative seesaw mechanism L L R Usually, more suppressions like (ml/v)p can appear depending on a model. Loop structure

  7. Radiative Seesaw Models :Lepton # line ✖：VEV :Lepton # Violation (2 units) :Exact Z2 line Zee (1980) Zee-Babu (1986) Ma (2006) Aoki-Kanemuera-Seto (2009) Krauss-Nasri-Trodden (2003)

  8. The Zee Model Zee, PLB93, 389 (1980) • Only the Higgs sector is extended from the SM (No RH neutrino) • Higgs sector:2-Higgsdoublets (Φ1, Φ2) + charged singlet (S±) • A softly-broken Z2 symmetry is imposed (Zee-Wolfenstein model).

  9. The Zee Model Zee, PLB93, 389 (1980) • Only the Higgs sector is extended from the SM (No RH neutrino) • Higgs sector:2-Higgsdoublets (Φ1, Φ2) + charged singlet (S±) • A softly-broken Z2 symmetry is imposed (Zee-Wolfenstein model).

  10. The Zee Model Zee, PLB93, 389 (1980) • Only the Higgs sector is extended from the SM (No RH neutrino) • Higgs sector:2-Higgsdoublets (Φ1, Φ2) + charged singlet (S±) • A softly-broken Z2 symmetry is imposed (Zee-Wolfenstein model). For tanβ = 1, mH2(1) = 400 (300) GeV, ml = mμ.

  11. Neutrino Mixing c.f. F : anti-symmetric For V13≪ 1, only the IH is possible. x > 0 [N.H.] x < 0 [I.H.] BUT

  12. Zee model with Type-III Yukawa • In this way, the simple Zee model has been excluded. Hasegawa, Lim, Ogure, 0303252 (PRD) He, 0307172 (EPJC) Sierra, Restrepo, 0604012 (JHEP) Garcca, Ohlsson, Riad, Wirn, 1701.05345 (JHEP), Etc… • A way out is to forget about the Z2 symmetry. • We can explain neutrino mixings, • but we have many parameters and the quark sector may also have FCNCs….

  13. We solved these two problems at the same time by a simple extension!!

  14. Our Extension Same particle content Global U(1) symmetry w/ flavor dependent charges This kind of model has been known as Branco-Grimus-Lavoura (BGL) models.

  15. Our Extension Same particle content Global U(1) symmetry w/ flavor dependent charges This kind of model has been known as Branco-Grimus-Lavoura (BGL) models. • Yukawa interaction Only Φ2 couples to quarks → No tree level FCNCs The structure of these couplings depend on the charge assignment.

  16. Structure of the Yukawa Matrices • Class I : qR =(0,0,-q), qL = qS = 0 • Class II : qR =0, qL = (0,0,q), qS = -q • Class III : qR =(0,0,-q), qL = (0,0,-2q), qS = q

  17. Analysis Neutrino masses Charged lepton masses

  18. LFVs of charged leptons Preliminary sin(β-α) = 1 mH = mA = mH1+ = 800 GeV mH2+ = 1000 GeV γ h, H, A H1±, H2± l’ l l’ l γ Inverted Hierarchy Normal Hierarchy

  19. LFV Higgs Decays Preliminary sin(β-α) = 1 mH = mA = mH1+ = 800 GeV, mH2+ = 1000 GeV H decay Normal Hierarchy Inverted Hierarchy In the NH case, BR(H → eτ) ≳ BR(H → eμ)

  20. Summary https://www.forbes.com/sites/brentbeshore/2013/04/17/ how-killing-two-birds-with-one-stone-kills-us-and-our-work/ • We got “2 birds with 1 stone”. Global U(1) symmetry Preliminary Another source of LFV No FCNCs in the quark sector • Characteristic pattern in the LFV Higgs decays • can appear. It can be a smoking gun sig. at LHC!

  21. LFV Higgs Decays sin(β-α) = 1, mH = 300 GeV Normal Hierarchy Inverted Hierarchy

  22. LFV Higgs Decays Normal Hierarchy Inverted Hierarchy

  23. Neutrino masses Class I Class II

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