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arXiv · 2204.05904

Measurement of the H$^3\Delta_1$ Radiative Lifetime in ThO

Daniel G. Ang·Cole Meisenhelder·Cristian D. Panda·Xing Wu·David DeMille·John M. Doyle·Gerald Gabrielse
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Abstract

The best limit on the electron electric dipole moment (eEDM) comes from the ACME II experiment [Nature \textbf{562} (2018), 355-360] which probes physics beyond the Standard Model at energy scales well above 1 TeV. ACME II measured the eEDM by monitoring electron spin precession in a cold beam of the metastable H$^3\Delta_1$ state of thorium monoxide (ThO) molecules, with an observation time $\tau \approx 1$ ms for each molecule. We report here a new measurement of the lifetime of the ThO (H$^3\Delta_1$) state, $\tau_H = 4.2\pm 0.5$ ms. Using an apparatus within which $\tau \approx \tau_H$ will enable a substantial reduction in uncertainty of an eEDM measurement.

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Daniel G. Ang, Cole Meisenhelder, Cristian D. Panda, Xing Wu, David DeMille, John M. Doyle, Gerald Gabrielse. 2022-04-12. Measurement of the H$^3\Delta_1$ Radiative Lifetime in ThO. https://doi.org/10.1103/physreva.106.022808

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