Affiliation at the time of the award:
Columbia University, USA
“for her persistent and successful exploration of the weak interaction which helped establish the precise form and the non conservation of parity for this new natural force.”
Professor Chien-Shiung Wu has done outstanding experimental work on the mechanism of beta disintegration, and thereby, of weak interactions generally. This work extended mostly from 1948 to 1963. In addition, she has made important contributions to several other fields of fundamental physics, to physics Instrumentation, and recently, to biology.
In her most famous work, she demonstrated that the direction of emission of beta rays is strongly correlated with the direction of the spin of the emitting nucleus. This showed that parity is not conserved in beta disintegration, in accord with the epochal theory of Lee and Yang, which had been developed just a few months before.
The success of this theory raised the problem of the exact coupling between the nucleon, which undergoes beta decay, and the electron and neutrino, which are emitted in this decay.
Among Wu’s other contributions we want to mention her demonstration that the two quanta from the annihilation of positrons and electrons are polarized at right angles to each other, as they should be according to Dirac’s theory. This proves that electron and positron have opposite parity. In recent years (1966 to 1971), Wu has made a thorough study of the X ray spectra of muonic atoms and has become interested in biological problems, especially the structure of hemoglobin. Her Moessbauer studies of this substance have given surprising results, and have considerably clarified its structure.