Chien-Shiung Wu (1912 - 1997) was a Chinese-American experimental physicist regarded as one of the foremost figures in nuclear and particle physics of the twentieth century. [1] Working at Columbia University, she designed and carried out the experiment that demonstrated the violation of parity conservation in weak interactions, confirming a theoretical prediction by Tsung-Dao Lee and Chen-Ning Yang. [1] She also contributed to the Manhattan Project and in 1978 received the inaugural Wolf Prize in Physics. [2]
Early life and education
Wu was born on 31 May 1912 in Taicang, in China's Jiangsu province, where her father ran a school for girls and encouraged her studies. [1] She graduated from National Central University in Nanjing and conducted research in China before emigrating to the United States in 1936. [1] She enrolled at the University of California, Berkeley, where she studied under Ernest Lawrence and completed a doctorate in physics in 1940. [2]
The Manhattan Project
After teaching at Smith College and Princeton, Wu joined Columbia University, where she took part in the Manhattan Project during the Second World War. [1] Her expertise in beta decay and radiation detection contributed to the enrichment of uranium by gaseous diffusion, and she helped identify xenon poisoning as the cause of a reactor that repeatedly stalled. [1]
Parity violation
In 1956 the theorists Tsung-Dao Lee and Chen-Ning Yang proposed that parity, the symmetry between a physical process and its mirror image, might not be conserved in the weak interaction. [1] Wu devised a test in which cobalt-60 nuclei were cooled to near absolute zero and aligned in a magnetic field so that the direction of the electrons they emitted could be measured. [1] The results, published in 1957, revealed a clear asymmetry, overturning a principle long assumed to be a law of nature. [2] Lee and Yang received the Nobel Prize in Physics that same year, though Wu, whose experiment supplied the decisive evidence, was not among the recipients. [1]
Later career and honors
Wu remained at Columbia for the rest of her career, continuing precise studies of beta decay and the conservation laws of physics. [3] In 1975 she became the first woman elected president of the American Physical Society and was awarded the National Medal of Science. [1] In 1978 she received the first Wolf Prize in Physics, and she was widely known as the First Lady of Physics for the rigor of her experimental technique. [3]
Legacy
Wu's work established that nature distinguishes between left and right at the subatomic level, a finding central to the development of the Standard Model of particle physics. [1] She died in New York City on 16 February 1997 and is remembered as a pioneer who opened experimental physics to later generations of women. [3]
