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60 Co and the Death of Parity

60 Co and the Death of Parity. Time Line. 1949: - Puzzle. Tau-Theta Puzzle. Tau-Theta Puzzle. •  + + + + - •  + + 0. Tau-Theta Puzzle. •  + + + + - •  + + 0 •P  =-1. Tau-Theta Puzzle. •  + + + + - •  + + 0 •P  =-1 •P  ≠P . Time Line.

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60 Co and the Death of Parity

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  1. 60Co and the Death of Parity

  2. Time Line 1949: - Puzzle

  3. Tau-Theta Puzzle

  4. Tau-Theta Puzzle •++++- •++0

  5. Tau-Theta Puzzle •++++- •++0 •P=-1

  6. Tau-Theta Puzzle •++++- •++0 •P=-1 •P≠P

  7. Time Line 1949: - Puzzle 1956: Lee and Yang

  8. Lee and Yang

  9. Lee and Yang •What if = ?

  10. Lee and Yang •What if = ? •Plenty of Evidence of P Conservation for Strong Force and EM

  11. Lee and Yang •What if = ? •Plenty of Evidence of P Conservation for Strong Force and EM •No Experimental Tests of P Conservation for Weak Force

  12. Lee and Yang •What if = ? •Plenty of Evidence of P Conservation for Strong Force and EM •No Experimental Tests of P Conservation for Weak Force •Does / Decay Violate Parity?

  13. Parity Violation

  14. Parity Violation

  15. Parity Violation Need a correlation between a vector (emission) and a pseudovector (spin)

  16. Time Line 1949: - Puzzle 1956: Lee and Yang 1957: 60Co  Decay

  17.  Decay Parity Violation Problems: Alignment of Nuclear Spin Measurement of Spin Alignment Cryogenics Solution: 60Co

  18. Reasons to Use 60Co Strong Magnetic Moment  Easy to Polarize • Emission Prefers Spin Axis  Measurement of Polarization Incorporation in a Crystal  Adiabatic Demagnetization to <1°K

  19. Co doped [2Ce(NO3)3•3Mg(NO3)2 •24H2O] cooled to .01°K

  20. Time Line 1949: - Puzzle 1956: Lee and Yang 1957: 60Co  Decay 1957: --e Channel

  21. --e Parity Violation Nevis Lab: 400MeV p+ Cyclotron p+ collision ++e+ Direction of + beam defines spin axis Look for asymmetries in spin alignment

  22. Publications: CS Wu, et al “Experimental test of parity conservation in beta decay.” Physical review, 1957 LM Lederman, RM Garwin, M Weinrich “Observations of the failure of conservation of parity and charge conjugation in meson decays: The magnetic moment of the free muon.” Physical review, 1957

  23. Conclusions:

  24. Conclusions: Don’t share paradigm shifting results until you’re ready to publish!

  25. Credit for images goes to: George L. Trigg. Landmark Experiments in Twentieth Century Physics. New York: Crane, Russak & co., 1975 C.S. Wu and S.A. Moszkowski. Beta Decay. Hoboken:John Wiley & Sons, 1966 Leon Lederman. The God Particle. Boston: Houghton Mifflin co., 1993

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