Wu Experiment on Parity Violation

Chien-Shiung Wu's 1956 parity violation experiment shattered the long-held assumption of mirror symmetry in physics by proving the weak nuclear force treats left- and right-handed systems differently. Cooling cobalt-60 to 0.01 K in a magnetic field, Wu measured 40% more electrons emitted opposite the nuclear spin direction, a definitive 5-sigma result. This finding is more definitive than the LIGO gravitational wave detection as a fundamental symmetry test, directly disproving a cornerstone assumption that had stood for decades.