1923-

American physicist who shared the 1980 Nobel Prize for Physics with collaborator James Cronin for their study of kaons. Fitch and Cronin's research demonstrated that the kaon and anti-kaon (the antimatter particle equivalent to the kaon) decayed with slightly different half-lives. This highly significant discovery led directly to the concept of Charge-Parity (CP) symmetry violation, the first time any symmetry law had been observed in nature.