C.S. Wu Photo Beta-Decay and Parity Nonconservation
(In the words of C.S. Wu*)
1913-1997
http://phys.columbia.edu/history/wu.htmlhttp://phys.columbia.edu/history/wu.html
hhttp://phys.columbia.edu/history/wu.html   (with minor modifications)ttp://phys.columbia.edu/history/wu.htmlkjll
...One day in the early spring of 1956, Prof. T.D. Lee came up to my little office on the thirteenth floor of Pupin Physical Laboratories. He explained to me, first, the tau - theta puzzle. If the answer to the tau - theta puzzle is violation of parity--he went on--then the violation should also be observed in the space distribution of the beta-decay of polarized nuclei: one must measure the pseudo- scalar quantity p.J, where p is the electron momentum and J the spin of the nucleus.

...Following Professor Lee's visit, I begin to think things through. This was a golden opportunity for a beta-decay physicist to perform a crucial test, and how could I let it pass? ...That spring, my husband, Chia-Liu Yuan, and I had planned to attend a conference in Geneva and then proceed to the Far East. Both of us had left China in 1936, exactly twenty years earlier. Our passages were booked on the Queen Elizabeth before I suddenly realized that I had to do the experiment immediately, before the rest of the Physics community recognized the importance of this experiment and did it first. So I asked Chia-Liu to let me stay and go without me.

...As soon as the spring semester ended in the last part of May, I started work in earnest in preparing for the experiment. ... In the middle of September, I finally went to Washington, D.C. for my first meeting with Dr. Amber. ...Between experimental runs in Washington, I had to dash back to Columbia for teaching and other research activities. On Christmas eve, I returned to New York on the last train; the airport was closed because of the heavy snow. There I told Professor Lee that the observed asymmetry was reproducible and huge. The asymmetry parameter was nearly -1. Professor Lee said that this was very good. This result is just what one should expect for a two-component theory of the neutrino.

...On the afternoon of January 15th, the Department of Physics at Columbia University called a press conference to announce the dramatic overthrow of a basic law of physics... . The news burst into public view and quickly spread around the world. As Professor O.R. Frisch of Cambridge University described it in a talk at that time, "The obscure phrase 'parity is not conserved' circled the globe like a new gospel.

* Excerpts from C.S. Wu's account in Adventures in Experimental Physics ("Gamma" volume), ed. B. Maglich (Princeton, World Science Communications, 1972), p.101.

At the January 15, 1957 news conference (held in Room 818 Pupin).
At table (from left): C.S. Wu and T.D. Lee
Second row: E. Ambler, R.P. Hudson and D.D. Hoppes (National Bureau of Standards).