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Oct 15 – 20, 2017
Harrison Hot Springs
Canada/Pacific timezone

Improved Measurement of the EDM of Mercury-199

Oct 16, 2017, 11:25 AM
Harrison Hot Springs

Harrison Hot Springs

100 Esplanade Avenue, Harrison Hot Springs, BC Canada V0M 1K0
Oral Other EDM searches (only overview talks) MoMo2


Dr Brent Graner (University of Washington)


This talk will cover the latest results on the permanent electric dipole moment (EDM) of neutral $^{199}$Hg atoms. The EDM is manifested as a small perturbation to the Larmor precession frequency due to the interaction energy of the electric dipole with a static electric field. The atoms are prepared in four separate glass vapor cells using optical pumping with resonant 254 nm laser light and allowed to precess in a common magnetic field and oppositely-directed electric fields. The precession frequency difference in a pair of cells is derived from the accumulated phase difference between two probe periods separated in time. Using this technique, we find the EDM projection onto the nuclear spin axis $d_{Hg} = (2.20 \pm 2.75_{stat} \pm 1.48_{syst}) \cdot 10^{-30} e\cdot \text{cm}$. While consistent with zero, this result places a new upper limit on the EDM $|d_{Hg}| < 7.4\cdot 10^{-30} e\cdot \text{cm}$ (95\% C.L.), improving the previous best limit by a factor of $>4$. $^{199}$Hg continues to have the most stringent limits for the EDM of any atomic or molecular system. The new limit constrains theories of physics beyond the Standard Model which incorporate new sources of time-reversal or $CP$ symmetry violation.

Funding Agency

This work was supported by NSF Grant No. 1306743 and the U.S. Department of Energy Office of Science, Office of Nuclear Physics under Award No. DE-FG02-97ER41020.


Primary author

Dr Brent Graner (University of Washington)


Prof. Blayne Heckel (University of Washington) Mr Eric Lindahl (University of Washington) Ms Yi Chen (University of Washington)

Presentation materials