FINALIST: Probing TeV Physics with the ThO Molecule: Twelve-fold Improved Measurement of the Electron's EDM

The Standard Model of particle physics accurately describes with amazing precision all particle physics measurements made in the laboratory. However, it is unable to answer basic cosmological questions, such as the nature of dark matter and why matter dominates over antimatter throughout the universe. New theories, such as models incorporating supersymmetry, contain massive particles whose interactions violate time-reversal symmetry, giving rise to an electric dipole moment (EDM) along the spin axis of the electron. In this talk, I will describe a new measurement of the electron's electric dipole moment, $d_e$=$(4.3 \pm 3.1_\mathrm{stat} \pm 2.6_\mathrm{syst})\times 10^{-30}$ $e \cdot \textrm{cm}$, obtained by measuring the spin precession of electrons subjected to the huge intramolecular electric field (78 GV/cm) accessible in the thorium monoxide (ThO) molecule. The resulting upper limit, $|d_e|<1.1\times 10^{-29}$~$e\cdot \textrm{cm}$, sets very strong constraints on the existence of new particles with masses far beyond the direct reach of the Large Hadron Collider. The sensitivity of our measurement, one order of magnitude better than any previous work, was made possible by sweeping technical improvements in our apparatus, such as increased state preparation efficiency that comes from introducing stimulated Raman adiabatic passage (STIRAP), and control and reduction of systematic effects. Future improvements in the search for EDMs using atoms and molecules promise to further advance the quest to find the new physics beyond the Standard Model that will help make it accurately describe our universe.