Professor Emeritus, Physics & Astronomy
School of Physical Sciences
PH.D., University of California, Berkeley, 1966
Phone: (949) 824-7209, 6373
Fax: (949) 824-2174
University of California, Irvine
3131 Frederick Reines Hall
Mail Code: 4575
Irvine, CA 92697
Experimental elementary particle and gravitational physics
Fellow, American Physical Society
Professor Newman was an undergraduate at Reed College and received his Ph.D. in experimental particle physics from UC Berkeley in 1966. He continued research in this field as an Assistant Professor at Columbia University and joined the UCI Physics faculty in 1973.
Many total surprises -- notably the violation of the fundamental symmetries of parity conservation and time reversal (or CPT) invariance -- have greeted physicists in this century. Parity violation might have been discovered much earlier than it was, had it occurred to physicists to look for such an "unlikely" possibility. What profound surprises lie in wait for us now? And how long might such surprises escape discovery in the pursuit of mainstream physics research?
Motivated by these questions, and building on a background in experimental elementary particle physics, my research focuses on possible exotic phenomena. With a postdoctoral fellow and a few students, I conduct "tabletop" experiments to test for physical possibilities which could escape observation in mainstream physics research. These experiments have included: a test of the rotational invariance of the weak interaction (might it recognize a preferred direction in space?); a search for advanced electromagnetic waves (traveling backwards in time) from a pulsed antenna; a precision test of the charge neutrality of helium atoms in liquid helium; and tests of the inverse square distance dependence and composition independence of the gravitational force at short range.
Current work in my lab focuses on:
Measurement of the gravitational constant G, (motivated by large discrepancies between results of G measurements by other groups in recent years), Searches for new extremely weak forces in nature with macroscopic range, and Tests of the equivalence of inertial and gravitational mass.
Ultrasensitive cryogenic torsion balances are being developed for these applications, which will be operated in a former Nike missile bunker at a remote desert site. (see Gravity Lab.)
Prospects for Terrestrial Equivalence Principle Tests with a Cryogenic Torsion Pendulum, Riley Newman, Class. Quantum Grav. 18, 2407 (2001)
Search for an Intermediate-Range Composition-Dependent Force Coupling to N-Z, (with P. G. Nelson and D. M. Graham), Phys. Rev. D42, 963 (1990).
Experimental Tests of the Gravitational Inverse-Square Law for Mass Separations from 2 to 105 cm, (with J. K. Hoskins, R. Spero, and J. Schultz), Phys. Rev. D32, 3084 (1985).
American Physical Society