Advanced cold molecule electron EDM

¹ Yale University Department of Physics, New Haven, CT, USA
² University of California Department of Physics and Astronomy, Los Angeles, CA, USA
³ Harvard University Department of Physics, Cambridge, MA, USA
⁴ Universität Innsbruck Institut für Experimentalphysik, Innsbruck, Austria
⁵ York University Department of Physics and Astronomy, Toronto, ON, Canada

^a e-mail: doyle@physics.harvard.edu

Abstract

Measurement of a non-zero electric dipole moment (EDM) of the electron within a few orders of magnitude of the current best limit of |d_e| < 1.05 × 10⁻²⁷ e⋅cm [1] would be an indication of physics beyond the Standard Model. The ACME Collaboration is searching for an electron EDM by performing a precision measurement of electron spin precession in the metastable H³Δ₁ state of thorium monoxide (ThO) using a slow, cryogenic beam. We discuss the current status of the experiment. Based on a data set acquired from 14 hours of running time over a period of 2 days, we have achieved a 1-sigma statistical uncertainty of δd_e = 1 × 10⁻²⁸ e⋅cm/√T, where T is the running time in days.