The metastable Q ${}^3{\Delta }_2$ state of ThO: A new resource for the ACME electron EDM search

Abstract

The best upper limit for the electron electric dipole moment was recently set by the ACME collaboration. This experiment measures an electron spin-precession in a cold beam of ThO molecules in their metastable $H{(}^3{\Delta }_1)$ state. Improvement in the statistical and systematic uncertainties is possible with more efficient use of molecules from the source and better magnetometry in the experiment, respectively. Here, we report measurements of several relevant properties of the long-lived $Q{(}^3{\Delta }_2)$ state of ThO, and show that this state is a very useful resource for both these purposes. The $Q$ state lifetime is long enough that its decay during the time of flight in the ACME beam experiment is negligible. The large electric dipole moment measured for the $Q$ state, giving rise to a large linear Stark shift, is ideal for an electrostatic lens that increases the fraction of molecules detected downstream. The measured magnetic moment of the $Q$ state is also large enough to be used as a sensitive co-magnetometer in ACME. Finally, we show that the $Q$ state has a large transition dipole moment to the $C{(}^1{\Pi }_1)$ state, which allows for efficient population transfer between the ground state $X{(}^1{\Sigma }^{+})$ and the $Q$ state via $X-C-Q$ Stimulated Raman Adiabatic Passage (STIRAP). We demonstrate $90$% STIRAP transfer efficiency. In the course of these measurements, we also determine the magnetic moment of $C$ state, the $X\to C$ transition dipole moment, and branching ratios of decays from the $C$ state.

arXiv comment21 pages, 6 figures, 5 pages appendices

References in corpus (19)

• Order of Magnitude Smaller Limit on the Electric Dipole Moment of the Electron
• Stimulated Raman adiabatic passage in physics, chemistry and beyond
• A precision measurement of the electron's electric dipole moment using trapped molecular ions
• The Buffer Gas Beam: An Intense, Cold, and Slow Source for Atoms and Molecules
• Search for the electric dipole moment of the electron with thorium monoxide
• Combined 4-component and relativistic pseudopotential study of ThO for the electron electric dipole moment search
• Interpreting the Electron EDM Constraint
• A cryogenic beam of refractory, chemically reactive molecules with expansion cooling
• A cryofuge for cold-collision experiments with slow polar molecules
• Methods, Analysis, and the Treatment of Systematic Errors for the Electron Electric Dipole Moment Search in Thorium Monoxide
• A buffer gas beam source for short, intense and slow molecular pulses
• Trapping of molecular Oxygen together with Lithium atoms
• Magnetic and electric dipole moments of the $H{}^3{\Delta }_1$ state in ThO
• Preparation and detection of states with simultaneous spin alignment and molecular orientation in PbO
• STIRAP preparation of a coherent superposition of ThO $H^3{\Delta }_1$ states for an improved electron EDM measurement
• Shot-noise-limited spin measurements in a pulsed molecular beam
• Optimized cell geometry for buffer-gas-cooled molecular-beam sources
• Attaining the shot-noise-limit in the ACME measurement of the electron electric dipole moment
• Thermometry of Guided Molecular Beams from a Cryogenic Buffer-Gas Cell

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