Improved limit on the permanent electric dipole moment of 199Hg

TL;DR

This paper reports a new, more stringent experimental upper limit on the electric dipole moment of 199Hg, enhancing constraints on CP violation beyond the standard model through advanced vapor cell measurements.

Contribution

It presents an improved experimental limit on 199Hg's electric dipole moment using a novel vapor cell setup, reducing the upper bound by a factor of 7.

Findings

New upper bound: |d(199Hg)| < 3.1 x 10^{-29} e cm

Improved sensitivity over previous measurements

Constraints on CP violation in physics beyond the standard model

Abstract

We report the results of a new experimental search for a permanent electric dipole moment of 199Hg utilizing a stack of four vapor cells. We find d(199Hg) = (0.49 \pm 1.29_stat \pm 0.76_syst) x 10^{-29} e cm, and interpret this as a new upper bound, |d(199Hg)| < 3.1 x 10^{-29} e cm (95% C.L.). This result improves our previous 199Hg limit by a factor of 7, and can be used to set new constraints on CP violation in physics beyond the standard model.