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Flavor Mixing of quarks

Flavor Mixing of quarks. The Standard Model. -. -. -. I. II. III. I. II. III. ? 3 families < ==> 3 colors ?. quark (2/3) neutrino quark (-1/3) charged lepton. lepton-quark family. weak decay of neutron. flavor mixing ( quarks – leptons ).

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Flavor Mixing of quarks

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  1. Flavor Mixing of quarks

  2. The Standard Model - - - I II III I II III ? 3 families < ==> 3 colors ?

  3. quark (2/3) neutrino quark (-1/3) charged lepton lepton-quarkfamily

  4. weak decay of neutron

  5. flavormixing (quarks – leptons)

  6. Lambda – decay:decay amplitude only about20 % of the neutron decay amplitude

  7. reducedby 80 %

  8. N. Cabibbo 1963 ( Cabibbo angle )

  9. thetermwith cos … = 0.974 has beenobserved in betadecay

  10. 1970:GIM – mechanism( Glashow, Iliopoulos, Maiani ) c: charmed quark

  11. GIM

  12. Nov: 1974: discovery of the psi mesonat SLAC – MIT( bound charm + anticharm )

  13. - flavor mixing angles fermion masses

  14. - - III 2 families flavor mixing II I

  15. (Cabibbo angle)

  16. mass matrices texture 0 u,c - d,s H. Fritzsch S. Weinberg 1978 ( beyond Standard Model )

  17. texture zeros in the electroweak gauge group SU(2,L) x SU(2,R) x U(1)

  18. texture zero: SU(2) x SU(2) Reflection symmetries (~parity) ===> Grand Unification

  19. Electroweak theory:SU(2) x SU(2) x U(1) In SO(10): lefthanded and righthanded neutrinos R L New energy scale for righthanded SU(2)

  20. U(1) x U(1) symmetry

  21. - ==> mass matrix

  22. - mixing angles <=> masses

  23. Cabibbo angle Exp.: phase 90 degrees ( symmetry ! )

  24. Cabibbo angle ==>

  25. - 3 families III flavor mixing II I

  26. - flavor mixing => CKM - matrix: three angles - one phase

  27. CKM matrix standard parametrization

  28. New parametrization: H. F. - Z. Xing

  29. - texture zeros:

  30. -

  31. - The angles and can be measured separately.

  32. SLAC DESY KEK FNAL CERN

  33. - theory:

  34. - theory:

  35. theory - x x theory -

  36. - unitarity triangle

  37. - - -

  38. Cabibbo angle Unitarity triangle (rectangular)

  39. Experiment:alpha 89.0 + 4.1/-4.2 degrees

  40. - Maximal CP-violation

  41. Unitaritytriangle:

  42. flavor mixing leptons

  43. Observed: 3 leptondoublets

  44. masses: electron: 0.51 MeV muon: 105.7 MeV tauon: 1 777 MeV neutrino masses: unknown but less than ~ 1 eV

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