The ACME electron electric dipole moment search

Observation of a non-zero electric dipole moment (EDM) of the electron, $d_e$, within a few orders of magnitude of the current limit $|d_e| < 1.05 \times 10^{-27}~e\cdot$cm would be an indication of CP violation in physics beyond the Standard Model. Numerous extensions to the Standard Model predict a value of $d_e$ in this range. The ACME Collaboration is searching for an electron EDM, by performing a precision measurement of spin precession signals from electrons in thorium monoxide (ThO) molecules. In this molecule, the EDM experiences a large electric field ($\sim\! 100$ GV/cm) that amplifies the spin precession. In addition, several properties of the molecular state make it possible to suppress many anticipated sources of systematic error. Our experiment uses a slow and bright cryogenic molecular beam to achieve unprecedented statistical accuracy. We now routinely take data with a 1$\sigma$ statistical uncertainty of $\delta d_e \approx 1.0-1.5 \times 10^{-28}/\sqrt{T}~e\cdot$cm, where $T$ is the running time in days. We will present the current status of the experiment.