Speaker
Description
A non-zero electric dipole moment (EDM) of a fundamental particle or a composite system, such as a nuclei, an atom, or a molecule, violates the time reversal symmetry, implying a violation of the combined charge conjugation and parity (CP) symmetry. The $^{199}$Hg EDM experiment has the most precise measurement on the frequency difference leading to an upper limit on the $^{199}$Hg EDM $\mid d_{Hg}\mid < 7.4 \times$ $10^{-30}$ e$\cdot$cm (95$\%$ C.L.) in 2016 without an internal electric field enhancement; it has provided a stringent constraint on new sources of CP violation beyond the Standard Model. This talk will describe the state-of-art techniques to instrument a set of mercury vapor cells, including the laser system to optically polarize and detect the spin-dependent interactions. $^{199}$Hg atoms are also applied in the neutron EDM experiment at Los Alamos National Laboratory. It is implemented both as the co-magnetometer, like the neutron EDM search at Paul Scherrer Institute (PSI), and as an external magnetometer inside the high voltage electrode to monitor the temporal fluctuation of the magnetic field background. I will describe the details of using $^{199}$Hg in both experiments.
This work is supported by the National Science Foundation, grant PHY-1828512.
