University Professor of Physics Emeritus, University of Chicago
in a series of experiments conducted at Brookhaven in 1964, Cronin and his colleague Fitch showed that in rare instances subatomic particles called K mesons violate CP symmetry during their decay. Important contribution to the understanding of the principles of symmetry governing elementary particles.
Corecipient with Val Logsdon Fitch of the 1980 Nobel Prize for Physics for an experiment that implied that reversing the direction of time would not precisely reverse the course of certain reactions of subatomic particles.
Research Corporation Award (with Val L. Fitch), 1968 John Price Wetherill Medal of the Franklin institute (with Val L. Fitch), 1975 Ernest 0. Lawence Award, 1977
Laureate of Lincoln Academy of Illinois ( Medal of Order of Lincoln), 1981
Member of the National Academy of Sciences,
Member of the American Academy of Arts and Sciences
Member of the American. Physical Society
Member of the American Philosophical Society