Val Logsdon Fitch

Val Logsdon Fitch (March 10, 1923 – February 5, 2015) was an American particle physicist whose experimental work revolutionized understanding of fundamental symmetries in nature. Alongside James Watson Cronin, Fitch discovered charge-parity (CP) violation in 1964 through analysis of neutral kaon decays at Brookhaven National Laboratory, revealing that certain symmetry principles previously thought absolute in particle physics were not universally upheld, a finding that earned them the 1980 Nobel Prize in Physics "for the discovery of violations of fundamental symmetry principles in the decay of neutral K-mesons." This breakthrough provided key insights into why matter predominates over antimatter in the universe and influenced subsequent theories in cosmology and quantum field theory. Earlier in his career, Fitch contributed to the Manhattan Project at Los Alamos as part of the Special Engineer Detachment, applying his physics expertise to wartime nuclear research. He later joined Princeton University in 1953, rising to full professor and continuing experimental particle physics until his retirement as Cyrus Fogg Brackett Professor Emeritus of Physics.