Cronin, James Watson
James Watson Cronin, 1931–, American nuclear physicist, b. Chicago, Ph.D. Univ. of Chicago, 1955. Cronin and co-researcher Val Logsdon Fitch were awarded the 1980 Nobel Prize in Physics for a 1964 experiment that proved that certain subatomic reactions do not adhere to fundamental symmetry principles. Specifically, they proved, by examining the decay of K-mesons, that a reaction run in reverse does not merely retrace the path of the original reaction, which showed that the reactions of subatomic particles are not indifferent to time.