Future Constraints on, and from Lepton Universality

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1 Future Constraints on, and from Lepton Melbourne Neutrino Theory Workshop June 2, 2008 Tatsu Takeuchi takeuchi@vt.edu Virginia Tech Tatsu Takeuchi, Melbourne, June 2, 2008 p.1/23

2 Collaborators Will Loinaz (Amherst College) Peter Fisher (MIT) Shawn Henderson (MIT) Alexey Pronin (Virginia Tech) Yee Kao (Virginia Tech) Tatsu Takeuchi, Melbourne, June 2, 2008 p.2/23

3 Potential of Future ν Experiments Future high statistics neutrino experiments will have the precision to probe new physics at the TeV scale. Fixed target ν-scattering experiments, e.g. NuSOnG. cf. arxiv: [hep-ph] Long baseline ν-oscillation experiments, e.g. Fermilab Hyper-Kamiokande. cf. arxiv: [hep-ph] Tatsu Takeuchi, Melbourne, June 2, 2008 p.3/23

4 Example: R-parity Violation W R = 1 2 λ ijk ˆL iˆlj Ê k + λ ijk ˆL i ˆQj ˆDk λ ijkûi ˆD j ˆDk, NuSOnG ( 95% ) current ( 95% ) M τl MẽR λ GeV) 100 GeV) M λ ( d M 0.06( dr 100 GeV 100 GeV Tatsu Takeuchi, Melbourne, June 2, 2008 p.4/23

5 RPV Contribution to ν-scattering ν µ λ 231 e R ν µ λ 211 d R/L τ L d L/R e R λ 231 ν µ d R/L ν µ λ 211 Tatsu Takeuchi, Melbourne, June 2, 2008 p.5/23

6 Current Bounds Current bounds on RPV come from CC lepton universality measurements: R τ = B(τ eν eν τ ) B(τ µν µ ν τ ) g µ /g e = ± R π = B(π eν e) B(π µν µ ) g µ /g e = ± = ± = (1.231 ± 0.004) 10 4 Tatsu Takeuchi, Melbourne, June 2, 2008 p.6/23

7 RPV contribution to τ and π decays ū λ 211 µ τ ν µ µ λ 231 ẽ R λ 231 ν τ d R d ν µ λ 211 Tatsu Takeuchi, Melbourne, June 2, 2008 p.7/23

8 In the Near Future: Current bounds on CC lepton universality can be expected to be improved dramatically in the near future. In the case of π-decay: aims to reduce the error on R π by a factor of 5. PEN@PSI aims to reduce the error on R π by a factor of 6. Combined, the error on R π will be reduced by a factor of 8. Tatsu Takeuchi, Melbourne, June 2, 2008 p.8/23

9 In the Near Future 2: τ-decay: Babar aims to reduce the errors on ALL one-prong τ branching fractions by factors of 3. Belle? W -decay: LEP2 sees 2σ difference in B(W τν τ ) vs. B(W µν µ ),B(W eν e ). Tevatron Run 2? Tatsu Takeuchi, Melbourne, June 2, 2008 p.9/23

10 Comparison of Babar and Belle: Integrated Luminosities: Babar: 557 fb 1 (data taking ended April 7, 2008) Belle: > 800 fb 1 and growing τ events Babar: 500 million τ pairs Belle: 700 million τ pairs and growing If Belle can analyze their data, the improvement will be much better! Tatsu Takeuchi, Melbourne, June 2, 2008 p.10/23

11 Potential Impact on RPV limits Babar ) ) λ 231 < 0.07 ( MẽR 100 GeV 0.03 ( MẽR 100 GeV PIENU+PEN λ 211 < 0.06 ( M dr 100 GeV ) 0.01( M dr 100 GeV ) Actual bounds could be stronger or weaker depending on whether the measured values are higher or lower than the SM. Tatsu Takeuchi, Melbourne, June 2, 2008 p.11/23

12 Global Analysis of CC Lepton Universality Allow the CC couplings to depend on lepton flavor: L = ( ) g l 1 W µ + ν l γ µ γ5 l + h.c l=e,µ,τ Fit all CC particle decay data with the parameters ǫ l, l = e,µ,τ. ( g l = g 1 ǫ ) l 2 Tatsu Takeuchi, Melbourne, June 2, 2008 p.12/23

13 Current Status: Tatsu Takeuchi, Melbourne, June 2, 2008 p.13/23

14 Comment on the Tevatron: The Tevatron ellipse is based on: 4 pb 1 of data from CDF Run 1 18 pb 1 of data from D0 Run 1 72 pb 1 of data from CDF Run 2 Total Integrated Luminosity delivered to each detector was: Run 1: >160 pb 1 Run 2: 4000 pb 1 and growing Tatsu Takeuchi, Melbourne, June 2, 2008 p.14/23

15 Tevatron Run 2 W Mass & Width Analyses CDF 200 pb 1 of data for W Mass W eν, W µν 350 pb 1 of data for W Width W candidates D0 177 pb 1 of data for W width W eν candidates 96 pb 1 of data W µν candidates Tatsu Takeuchi, Melbourne, June 2, 2008 p.15/23

16 Blowup of Current Status: Tatsu Takeuchi, Melbourne, June 2, 2008 p.16/23

17 With improved π and τ branching fractions: Tatsu Takeuchi, Melbourne, June 2, 2008 p.17/23

18 With improved τ lifetime: Tatsu Takeuchi, Melbourne, June 2, 2008 p.18/23

19 Neutrino Mixing with Gauge Singlet States ν = ν light cos θ + ν heavy sinθ χ = ν light sin θ + ν heavy cosθ Zνν = Zν light ν light cos 2 θ +2Zν light ν heavy sinθ cos θ +Zν heavy ν heavy sin 2 θ Wlν = Wlν light cos θ + Wlν heavy sinθ ( Zν l ν l (1 ǫ l ) Wlν l 1 ǫ ) l 2 Tatsu Takeuchi, Melbourne, June 2, 2008 p.19/23

20 With LEP/SLD data: Fit with S, T, ε e, and ε µ. Tatsu Takeuchi, Melbourne, June 2, 2008 p.20/23

21 Potential Impact of NuSOnG: Fit with S, T, ε e, and ε µ. Tatsu Takeuchi, Melbourne, June 2, 2008 p.21/23

22 Conclusions: Bounds on CC Lepton Universality can be expected to be improved dramatically in the near future by new data (PIENU, PEN) and the analysis of already existing ones (Babar, Belle, Tevatron). Such improvements will place strong constraints on certain types of New Physics which will be difficult to beat even with future high statistics ν experiments. (e.g. certain R-parity violating couplings) Tatsu Takeuchi, Melbourne, June 2, 2008 p.22/23

23 Conclusions continued: When combined with future high statistics ν experiments, they can yield very stringent bounds on other types of New Physics. (e.g. neutrino mixing with heavy gauge singlet states) When are the Belle and Tevatron Run 2 analyses coming out? Tatsu Takeuchi, Melbourne, June 2, 2008 p.23/23

Lepton non-universality at LEP and charged Higgs

Lepton non-universality at LEP and charged Higgs Jae-hyeon Park TU Dresden Institutsseminar TU Dresden, 13.10.2011 Standard Model L SM = 1 4 F F+ ψi/dψ [H ψ L Y ψ R+ h.c.] + g2 θ 32π 2 F F+ DH 2 V(H) Omitted: