MASSIVE NEUTRINOS IN A GROUNDS-UP APPROACH WITH QUARK-LEPTON SIMILARITY

1. MASSIVE NEUTRINOS IN A GROUNDS-UP APPROACHWITH QUARK-LEPTON SIMILARITY Amarjit Soni HET, BNL (soni@bnl.gov) with David Atwood&Shaouly Bar-Shalom Based on: Phys. Lett. B (2006)&… Hanoi Aug. '06

2. OUTLINE • Introduction • Two Higgs doublet model for the top quark (t2HDM) • Incorporating the leptons in a “natural” set up -> a two Higgs doublet model “for the 3rd generation”(3g2HDM)….invoke quark<->lepton similarity • Masses, mixing angles & -oscillations in the 3g2HDM • Leptogenesis in the 3g2HDM : significantly enhanced • CP-asymmetry -> evading (usual) bound on (lightest) • Majorana mass and on the consequent reheating temp. • Summary & outlook Hanoi Aug. '06

3. Introduction Gonzales-Garcia, hepph/0410030; Fogli et al, hepph/0506083 Hanoi Aug. '06

4. Introduction • 2 monumental discoveries of the 90’s:mt ~ mGold>>mu,d,c,s,bm 0 << eV Are they related? Based on the beautiful seesaw mechanism: • A strong hint for • Large Dirac -mass : • Super-heavy Majorana neutrinos : Hanoi Aug. '06

5. The goal of this workto suggest a natural relation between the:1) large mt2) observed -oscilations3) superheavy Majorana mass scale in a two Higgs doublet model, based on a grounds-up approach with quark-lepton similarity the 2HDM “for the 3rd generation” (3g2HDM) (assumes same status for the top-quark and the 3rd generation rh-) Hanoi Aug. '06

6. Main output of the model • “Predictions” • 42.90 < atm < 45.20 • -0.960 < 13 < 1.360 • In fact model leads to a simple relation: • atm ~ π /4 - | 13 | • The CP asymmetry for leptogenesis • via(N1-> l φ1 ) is significantly enhanced • over models with 1 Higgs doublet or over SUSY-like models Hanoi Aug. '06

7. Two Higgs doublet model for the top quark[Das & Kao’96] (t2HDM) I) To accommodate the huge mass of the top quark, the Yukawa’s are chosen so that the second Higgs doublet, with a much larger VEV than the 1st one couples ONLY to the top quark; the 1st Higgs doublet couples to all the other quarks and leptons…giving rise naturally to a large tan β =v2/v1>>1 and a large top mass. Hanoi Aug. '06

8. Incorporating the ν’s • II)We propose a very simple generalization • of t2HDM in which the second Higgs doublet, φ2 (with a much larger VEV) couples not only to the top quark but also to the 3rd generation N. Hanoi Aug. '06

9. KEY PARAMETER of the MODEL tanβ(>>1) A simple Extension of the 2HDM “for the top quark” (Das&Kao PLB1996): • Basic idea: large top mass is quite naturally accounted for by assuming vt/vq(=tanβ)>>1t couples only to the top-quarkq couples to all other quarks N = r.h. Majorana neutrinos The Two Higgs doublet Model “for the 3rd generation” (3g2HDM) A minimal LEET which captures the dominant features of phenomenology, and models some underlying dynamics of EW symmetry breaking relevant to distances much shorter than the EW- scale Hanoi Aug. '06

10. Two Key Points • t2HDM may be regarded as an LEET for an underlying model of EWSB such as top-condensation model (Bardeen, Hill and Lidner) or the top-color model (Hill) or in fact models based on EXTRA-DIM e.g. RS • Since NFC is not being implemented in Higgs couplings, we should expect • necessarily fcnc (ex. Of Mod III) but very restrictive as fcnc involves only tc, tu and NOT d,s.b Hanoi Aug. '06

11. New&rich phenomenology of the 3g2HDM in the quark sector • Enhanced H+cb Yukawa: H+cb  Vtb(not Vcb!) • Enhanced H0cc Yukawa: H0cc  mctan (not mc/tan !) • New tree-level FCH0tc & H0tu couplings (no FCNC in d-quark sector!)implications for:CPV in B-physics(Kiers,Soni,Wu: PRD1999, PRD2000)FC Z-decays(Atwood,Bar-Shalom,Eilam,Soni: PRD2002) b-jet & c-jet physics in hadron colliders Hanoi Aug. '06

12. 3g2HDM (cont.) Our Anzats: Quark-lepton similarity: (SIGNIFICANT REDUCTION in # of params.) (Y2)13=0 : avoid fine-tuning for -oscilation (e.g.,(Y1)31= (Y2)13<< (Y1,2)ij13,31 from vanishingly small overlap of corresponding N & L wave-functions in ED-models(Raidal&Strumia PLB2003)or from some flavor symmetry of the underlying short-distance theory) {see, e.g. Grimus, Joshipura, Lavoura & Tanimoto, EuPhJC2004} Hanoi Aug. '06

13. Implementing quark-lepton simlarity • Note that the same elements (a,b,c..) in the • Yukawa matrix appear for quarks, ν • To get u-quark-ordering right: • a~O(10-3),b~O(10-1),c~O(1) • also for neutrinos. • This key assumption of quark-lepton similarity renders the scenario with normal • hierarchy most natural Hanoi Aug. '06

14. mu ~ avq mc ~ bvq mt ~ cvq ta ~ O(10-3) b ~ O(10-1) c ~ O(1) , With: 3g2HDM (cont.) Our Anzats :Quark-lepton similarity t=tan ~ O(10) key parameter # of Params: 4 + 3 Seesaw in the basis : Hanoi Aug. '06

15. heaviest M M mass-scale -oscillations (cont.) Masses and mix. Angles: t-ν-N Seesaw Connection Normal hierarchy (m3>>m2>>m1) & Natural Mass Scales Hanoi Aug. '06

16. Correlations in the mixing angles • Study a scatter plot of the allowed ranges • subject to the 3 σ allowed limits. This is done by randomly varying the 3 input parameters (ε,r,δ) with a sample of 3X106 points. Hanoi Aug. '06

17. Hanoi Aug. '06

18. mixing angles Numerical Results & Implications masses Hanoi Aug. '06

19. Numbers for -oscillations at 3 mixing angles at 99% CL masses Hanoi Aug. '06

20. best fitted parameters from -oscillation: • quark-lepton similarity: r ~ 1 ,  ~ 0.6 ,  ~ 5.3 a ~ O(10-3) , b ~ O(10-1) , c ~ O(1) Heavy Majorana Spectrum in the 3g2HDM Will find:MN1 ~ 109 – 1010 GeV << MN2 , MN3 Hanoi Aug. '06

21. # density of Ni asymmetry washout CPV asymmetry in the decays Ni  L spheleron processes Leptogenesis in the 3g2HDM In the 3g2HDM (with MN1 << MN2 , MN3 ): Washout determined by the “decay parameter” K=N1/H(T~MN1)For e.g., 109<MN1/GeV< 1010 (6<K<60) CP-asymmetry from: a,b=arg(a,b) (a good fit to the numerical solution of the B-eqs. – see e.g., Di Bari, hep-ph/0406115) Hanoi Aug. '06

22. Origin of the enhanced CP asymmetry • The enhancement in the CP asy. in this model is due to the presence of the 2nd Higgs doublet which sets the scale of EWSB (v2 ) but that is now decoupled • from v1 that determines the light neutrino mass spectrum…Indeed CP asy. in our model is enhanced over SM and SUSY-models by tan2β ~100 Hanoi Aug. '06

23. For best fitted parameters (,m2sol) & tan ~ O(10): Compatible with observed value nB/s ~ 8.510-11if e.g.,MN1 ~ 1010 GeV & sin2(b- a) ~ 0.1 Or (max. CP): MN1 ~ 109 GeV & sin2(b- a) ~ 1 Overall Baryon asym. in the 3g2HDM Hanoi Aug. '06

24. SUMMARY & OUTLOOK -> Favors normal hierarchy • 3g2HDM: an effective grounds-up approach based on quark-lepton similaritykey parameter: tan  O(10) in order to explain mt • Predictions: • a triple t -  - N seesaw connection: • Easily fits -oscillation data but gives a very restricted: • -0.960 < 13 < 1.360(3) • 42.90 < atm < 45.20 (3) • MN1 ~ 109-1010 GeV, MN2~1011 GeV,MN3~ 1015 GeV • Baryogenesis through Leptogenesis with:CP-asym. ~ tan2·max(SM or MSSM) atm ~ π /4 - | 13 | Hanoi Aug. '06

25. Backups Hanoi Aug. '06

26. Discrete Symmetry for t2HDM Das&Kao, PLB’96 Hanoi Aug. '06

27. Leptogenesis from CP-asymmetry Niin the decays Ni  L # density of Ni asymmetry washout a,b=arg(a,b) spheleron processes CPV/L#V asymmetry Niin the 3g2HDM (for MN1 << MN2 , MN3 ): Hanoi Aug. '06

28. for e.g., 109<MN1/GeV< 1010  6<K<60 (the mildly strong washout regime: strong enough to be almost independent of the initial conditions but not too strong to result in a significant efficiency loss) (a good fit to the numerical solution of the B-eqs. – see e.g., Di Bari, hep-ph/0406115) Leptogenesis in the 3g2HDM (cont.) washout: determind by the “decay parameter”K which measures the amount of asymmetry-damping caused by the inverse N1 decay: Hanoi Aug. '06

29. # density of Ni asymmetry washout CPV asymmetry in the decays Ni  L spheleron processes Leptogenesis in the 3g2HDM In the 3g2HDM (with MN1 << MN2 , MN3 ): Washout determined by the “decay parameter” K=N1/H(T~MN1)For e.g., 109<MN1/GeV< 1010 (6<K<60) CP-asymmetry from: a,b=arg(a,b) (a good fit to the numerical solution of the B-eqs. – see e.g., Di Bari, hep-ph/0406115) Hanoi Aug. '06