Stephen Matthew Barr[1] (born November 28, 1953) is an American physicist who is a professor emeritus of physics at the University of Delaware.[2] A member of its Bartol Research Institute, Barr does research in theoretical particle physics and cosmology. In 2011, he was elected Fellow of the American Physical Society, the citation reading "for original contributions to grand unified theories, CP violation, and baryogenesis."[3]
His notable work includes co-discovering the much studied flipped SU(5) scheme of unification, identifying the Barr–Zee diagram as an important source of electric dipole moment for basic particles such as the electron and neutron in many theories, and proposing the so-called Nelson–Barr mechanism as a solution to the strong CP problem. He is the author of the article on "Grand Unified Theories" for the Encyclopedia of Physics.
Barr received his PhD in theoretical particle physics from Princeton University in 1978. Princeton awarded him the Charlotte Elizabeth Proctor Fellowship "for distinguished research." He went on to do research at the University of Pennsylvania as a post-doctoral fellow (1978–80), the University of Washington as a research assistant professor (1980–85), and Brookhaven National Laboratory as an associate scientist (1985–87), before joining the faculty of the University of Delaware in 1987. He was elected director of the Bartol Research Institute of the University of Delaware in 2011.
Barr, a practicing Catholic,[4] writes and lectures frequently on the relation of science and religion. From 2000 to 2017 he served on the Editorial Advisory Board or Advisory Council of the ecumenical religious intellectual journal First Things, in which many of his articles and book reviews have appeared since 1995.[5] His writing has also appeared in Commonweal, National Review, Modern Age, The Public Interest, America, The Wall Street Journal, and other publications. In 2002 he gave the Erasmus Lecture, sponsored by the Institute on Religion and Public Life. In 2007 he was awarded the Benemerenti MedalbyPope Benedict XVI. In 2010 he was elected a member of the Academy of Catholic Theology. He is also president of the Society of Catholic Scientists.[6]
^"Nuclear and High-Energy Physics". Scientific and Technical Aerospace Reports. 17 (1). National Aeronautics and Space Administration: 392. January 8, 1979.
