Parity Violations

Authors(s):David Bugg Publication:Physics World Publication Date: Publisher: Citation: Link:
In January 1958 I attended the meeting of the American Physical Society in New York where Wu presented the results of her experiment on parity violation in beta decay of cobalt-60. In a 20 minute talk she described the experiment and announced that the result was that beta-decay indeed violated parity conservation and the combination of amplitudes was S+T, the sum of the scalar and tensor currents. 
After the applause, Richard Feynman, who was sitting a few rows behind me, spoke up slowly and dramatically in his broad Brooklyn accent with the words “That’s gotta be wrong!” He then explained briefly that he and Murray Gell-Mann had constructed a theory which predicted an amplitude of V – A, where V and A are the vector and axial vector currents, respectively. The idea of the theory was that the vector current is conserved, as in electromagnetism, and the axial current is partially conserved.
In the afternoon, there was a public announcement that there would be an extra nuclear physics session in the evening with an announcement from Wu. I attended, of course, and she calmly stated that she had been through her notebooks, and there was a sign error. Feynman was right: the results required V – A. Sometime later, the nuclear physicist Maurice Goldhaber told me that there had been active discussion behind the scenes before the meeting with Isidor Rabi and others on the correct sign, but he did not know if Wu was involved in the discussions. My impression was that the theorists got together with her in the afternoon and helped sort out the sign error.