Overview
The Wu experiment was a particle and nuclear physics experiment conducted in 1956 by the Chinese-American physicist Chien-Shiung Wu in collaboration with the Low Temperature Group of the US National Bureau of Standards. The experiment's purpose was to establish whether conservation of parity, which was previously established in the electromagnetic and strong interactions, also applied to weak interactions. If parity conservation were universal, particle decays governed by the weak interaction would behave similarly to particle decays involving the other interactions. A parity transformation negates the coordinates in a theory, creating a mirror image. If the predictions of the theory are not altered, it is said to "conserve parity". Objects spinning clockwise appear to spin counterclockwise in their mirror image. The Wu experiment created an atomic system with spin, then compared weak-interaction particle decay for spins clockwise and counterclockwise.