Walsworth Group Improves the Limit on Violations of Standard Model Extensions

Ron Walsworth, an investigator at the Smithsonian Astrophysical Observatory, reports the acceptance for publication by Physical Review A of the paper "Testing Lorentz and CPT symmetry with hydrogen masers," with authors M.A. Humphrey, D.F. Phillips, E.M. Mattison, R.E. Stoner, R.F.C. Vessot, and R.L. Walsworth. In this paper the authors present details from a recent test of Lorentz and CPT symmetry using hydrogen masers. They have placed a new limit on Lorentz and CPT violation of the proton in terms of a recent standard model extension by placing a bound on sidereal variation of the F = 1 Zeeman frequency in hydrogen.

Walsworth also reports that graduate student Marc Humphrey received a PhD in Physics from Harvard University in June, 2003 for a thesis entitled "Precision Measurements with Atomic Hydrogen Masers."