During his career, he contributed to general relativity, the theory of weak interactions and models for elementary particles based on the mathematical description of knots.
Peccei and a colleague theorized a symmetry that predicts the existence of very light particles called axions, which may be the dominant source of mass in the universe.
Dr. William “Billy” Cunningham, professor of medicine at the David Geffen School of Medicine at UCLA and health policy and management in the Fielding School of Public Health, died Jan. 2.