Wu, Chien-shiung (1912?– ), U.S. experimental physicist. In 1957 her experiments in particle physics disproved the law of the conservation of parity, a long-held theory that the direction in which beta particles are emitted from a radioactive nucleus is not related to the direction of spin of the nucleus. Her work confirmed the theory of physicists Tsung Dao Lee and Chen Ning Yang (who shared the 1957 Nobel Prize in physics) that the direction of spin affects the predominant direction of such emissions. Her experimental work also helped confirm theoretical work of Richard P. Feynman and Murray Gell-Mann. Wu emigrated from China to study at the University of California, Berkeley. She worked at Columbia University from 1944, first in the Division of War Research and after 1957 as a professor.