2. weak decays beta decay ofneutron

3. problem energy and momentum not conserved e n p

4. W. Pauli: 1930  Neutrino mass ~ m(e)

5. weak decays beta decay ofneutron

6. e n p

7. direct interaction of four fermions  Enrico Fermi, ~1936 p n electron antineutrino

11. weak interactions current-current interaction weak currents ~ lefthanded:

12. lefthanded fermion S= - 1/2 righthanded antifermion S = + 1/2

13. maximal breaking of parity

14. weak interaction of the quarks beta – decay d  u

15. weak decays of strange particles ( u d s )( u u d ) s  u

16. Cabibbo angle:  flavor mixing

19. 19

24. W(+) W(-) Z photon

29. rotation symmetry spontaneous symmetry breaking in classical mechanics

30. spontaneous symmetry breaking baki

31.  direction singled out  rotation symmetry broken

33. Peter Higgs

34. Kibble Guralnik Hagen Englert Brout

35. potential V example 1: real scalar field

41. => 2 ground states

43. example 2: complex scalar field

51. exact symmetry: broken symmetry:

53. scalars: doublet

56. degrees of freedom before symmetry breaking:

57. After symmetry breaking:

58. scalars: triplet

61. „Higgs“ scalar

72. photon

76. first term lefthanded  parity violation

77. neutral current interaction parity violation observed in atomic physics

81. neutrino massless (only lefthanded component)

82. The masses of the weak bosons are predicted, once the weak angle is measured. The electron mass cannot be predicted ( the coupling constant g is unknown ).

83. electroweak theory: mass generation by ??? SSB ??? QCD: mass generation by confinement problem: mass generation

84. hypothetical Higgs boson

86. L3 I ATLAS CMS LHCb Alice

90. December 2011: ATLAS and CMS report signal at 125 GeV decay into Z + Z W + W, photon + photon

91. Real World 3 lepton-quark families mass

92. Real World 6 leptons – 6 quarks 2 x 3 doublets

93. flavormixing