1 / 29

The tau Lepton

The tau Lepton. and. Flavour Violation. Mass Origin and Supersymmetry March 6 -8 2006 Tsukuba. Achim Stahl RWTH Aachen University. t -  m - n m n t. n  p e - n e. t -decays:. Lepton Number. L i = Σ # Leptons Gen i – # Antileptons Gen i. conserved in the Standard Model.

dbrownfield
Télécharger la présentation

The tau Lepton

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The tau Lepton and Flavour Violation Mass Origin and Supersymmetry March 6 -8 2006 Tsukuba Achim Stahl RWTH Aachen University

  2. t-  m- nm nt npe- ne t-decays: Lepton Number Li = Σ # LeptonsGen i – # AntileptonsGen i conserved in the Standard Model today: many examples Wolfgang Pauli

  3. nt nm Neutrino Oscillations neutrino oscillations violate lepton number !

  4. annihilation nm nt Leptonic tau-Decay nt t- nm W- m- t-  m- forbidden: nm nt

  5. neutrino oscillation nm Leptonic tau-Decay nt t- nm W- m- t-  m- forbidden: nm nt but: energy/momentum conservation

  6. neutrino oscillation nm g LFV-Decay possible decay nt t- nm W- m- t-  m- g forbidden: nm nt but: energy/momentum conservation

  7. LFV-Decay possible decays nt t- nm m- W- g/Z m+ m- t-  m- m+ m-

  8. LFV-Decay possible decays nt r0 Z t- nm W- m- t-  m- r0

  9. neutrino oscillation nm g GIM-Mechanism nt t- nm W- m- t-  m- g

  10. Ue1 Ue2 Ue3 Um1 Um2 Um3 Ut1 Ut2 Ut3 ne nm nt n1 n2 n3 = 1 0 0 0 1 0 0 0 1 Ue1 Um1 Ut1 Ue2 Um2 Ut2 Ue3 Um3 Ut3 Ue1 Ue2 Ue3 Um1 Um2 Um3 Ut1 Ut2 Ut3 unitarity condition * * * * * * * * * g = t-  m- g A  SUti Umif(mi2) ≈ 0 A  SUti Umi = ? A  SUti Umi = 0 * * * GIM-Mechanism ni t- Uti W- * Umi m- br ≈ 10-40

  11. The Paper of X.-Y. Pham Is this true ? Euro Phys J C8 (1999) 513, hep-ph/9810484 for discussion see Tord Riemanns home-page http://www-zeuthen.desy.de/~riemann/

  12. Beyond the S.M. new physics breaks GIM

  13. mg mmm SUSY SO(10) NPB649(2003)189 PRD68(2003)033012 10-8 10-10 SUSY HIGGS PLB549(2002)159 PLB566(2003)217 10-10 10-7 mSUGRA EPJC14(2000)319 PRD66(2002)115013 10-7 10-9 non-universal Z´ PLB547(2002)252 10-9 10-8 Heavy Maj. NRPRD66(2002)034008 10-9 10-10 Some theoretical estimates Beyond the S.M. new physics breaks GIM

  14. Experimental Searches

  15. t-  m- nm nt g t-  m- g Experimental Searches Signal: Background: e+e- m+m-g e+e- t+t- _ e+e- q q

  16. LVF @ b-factories currently best limits ! BaBar approaching 109t-pairs t-  m- g Belle 2004: < 3.1 10-7 BaBar 2005: < 6.8 10-8

  17. LVF @ b-factories currently best limits ! BaBar approaching 109t-pairs prel. ’03 final ‘05 t-  m- g • (r/e-tag) 5.2 % 3.8 % • (total) 9.4 % exp. BGD (r/e) 7.8 ev. 2.8 ev. (total) 6.2 ev. limit (10-8) < 200 < 6.8 Belle 2004: < 3.1 10-7 BaBar 2005: < 6.8 10-8 b-factories reaching the limits at x 10-8

  18. LVF @ LHC t sources at the LHC: 1 year running low luminosity p p  W  t nt p p  Z/g  t t p p  B0  t X p p  B±  t X p p  Bs  t X p p  Ds  t X 1.7 108 8.0 108 4.0 1011 3.8 1011 7.9 1011 1.5 1012 plenty of taus ! no chance to see t- m- g

  19. LVF @ LHC  Tryt-  m- m+ m- Simulation with underlying event low luminosity

  20. LVF @ LHC Source: W  t nt Trigger: Single-Muon L1: pT > 14 GeV HLT:pT > 19 GeV Trigger: Di-Muon L1: pT > 3 GeV HLT:pT > 7 GeV Looks okay 1.7 108t per year

  21. LVF @ LHC DS - Source Trigger: Single-Muon L1: pT > 14 GeV HLT:pT > 19 GeV Trigger: Di-Muon L1: pT > 3 GeV HLT:pT > 7 GeV Trigger-Eff. only 1% 1.5 1012t per year

  22. LVF @ LHC Background Problem with DS source DS F m nm 1 % br. F  m m (g) 10-5br. Does anybody know of a generator for this process ?

  23. LVF Z-Decays m+ g/Z nt m- t- nm m- W- t-  m- m+ m-

  24. LVF Z-Decays m- g/Z m+ nt t- nm m- W- m- m+ t- m-

  25. LVF Z-Decays m- g/Z m+ nt nm m- m- m+ m- t+ t+

  26. LVF Z-Decays p g/Z p nt nm m- p p  Zm- t+ t+

  27. LVF Z-Decays m- nm p g/Z W p nt t+ p p  Zm- t+

  28. Summary

  29. Conclusions LFV tau-decays  Interesting search for physics beyond the S.M. (SUSY and others ) b-factories will approach 10-8 Can we improve a few channels at LHC ? Also look for LVF in Z-decays at LHC !

More Related