1. 60 Co and the Death of Parity

2. Time Line 1949:  -  Puzzle

3. Tau-Theta Puzzle

4.  + +  + +  -  + +  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. 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

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

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

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

18. Reasons to Use 60 Co 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(NO 3 ) 3 3Mg(NO 3 ) 2 24H 2 O] cooled to.01°K

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

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

26. 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

27. Conclusions:

28. Don’t share paradigm shifting results until you’re ready to publish!

29. 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