title: Reduced Limit on the Permanent Electric Dipole Moment of ^{199}Hg.
abstract: This Letter describes the results of the most recent measurement of the permanent electric dipole moment (EDM) of neutral ^{199}Hg atoms. Fused silica vapor cells containing enriched ^{199}Hg are arranged in a stack in a common magnetic field. Optical pumping is used to spin polarize the atoms orthogonal to the applied magnetic field, and the Faraday rotation of near-resonant light is observed to determine an electric-field-induced perturbation to the Larmor precession frequency. Our results for this frequency shift are consistent with zero; we find the corresponding ^{199}Hg EDM d_{Hg}=(-2.20±2.75_{stat}±1.48_{syst})×10^{-30}e cm. We use this result to place a new upper limit on the ^{199}Hg EDM |d_{Hg}|<7.4×10^{-30}e cm (95% C.L.), improving our previous limit by a factor of 4. We also discuss the implications of this result for various CP-violating observables as they relate to theories of physics beyond the standard model.
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: B
authors.initials: B
authors.lastname: Graner
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: Y
authors.initials: Y
authors.lastname: Chen
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: E G
authors.initials: EG
authors.lastname: Lindahl
authors.affiliation: Department of Physics, University of Washington, Seattle, Washington 98195, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Heckel