Cronin, James Watson (1931-2016), an American nuclear physicist, shared the 1980 Nobel Prize for physics with fellow American Val Fitch . They were awarded the prize for an experiment that suggested that reversing the direction of time would not produce an exact reversal of certain reactions involving subatomic particles. Their research on subatomic particles known as kaons revealed that the fundamental laws of symmetry in nature, which include time reversal, could be violated. Before this, physicists had assumed that the direction of time would not affect the way in which reactions work. Although scientists still do not fully understand this result, they use it to explain why matter dominates antimatter in the universe. See Subatomic particle ; Antimatter .
James Watson Cronin was born in Chicago on Sept. 29, 1931. In 1955, he received a doctorate from the University of Chicago. He then joined the staff of the Brookhaven National Laboratory in New York. In 1958, he became a professor at Princeton University in New Jersey. From 1971 to 1997, he was a professor at the University of Chicago. Cronin died on Aug. 25, 2016.
