A New Limit on the Electron Electric Dipole Moment

The charge distribution associated with an electron has surprising implications for a number of outstanding mysteries in physics. Why is the universe made out of matter versus anti-matter, instead of both equally? What new particles and interactions lie beyond the current reach of accelerators like the LHC? Models which propose answers to these questions, such as Supersymmetry, tend to predict a small, yet potentially measurable, asymmetric interaction between an electron and an electric field, characterized by an electric dipole moment (EDM). Despite over six decades of experimental searching, no EDM of any fundamental particle has ever been measured; however, these experiments continue to provide some of the most stringent limits on new physics. Here, we present the results of a new search for the electron EDM, $\de = (-2.1 \pm 3.7_\mathrm{stat} \pm 2.5_\mathrm{syst}) \times 10 {-29}$ e cm, which represents an order of magnitude improvement in sensitivity from the previous best limit. Since our measurement is consistent with zero, we present the upper limit of $|\de| < 8.7\times 10 {-29}$ e cm with 90 percent confidence.