Progress Towards a Measurement of the Electric Dipole Moment of the Electron*

We have proposed a measurement of the electric dipole moment of the electron ($d_e$) using the metastable a(1) ($^3\Sigma^+$) state of the PbO molecule. A non-zero measurement of $d_e$ within the next few orders of magnitude beyond the current limit of (6.9 $\pm$ 7.4) $\times$ $10^{-28}$ e-cm[1] would be clear evidence for physics beyond the standard model. We will present recent results from and improvements to our experiment including a proof of principle for the experiment, recent data on the initial state preparation using stimulated microwave Raman transitions, and a new detection system. The new detection system uses Winston Cone optical concentrators and large-area, low-noise, high speed, photodiode-based fluorescence detectors with fast overdrive recovery [2].\newline \newline [1] B. C. Regan, Eugene D. Commins, Christian J. Schmidt, and David DeMille, Phys. Rev. Lett. \textbf{88}, 071805 (2002) \newline [2] S. Bickman and D. DeMille, Rev. Sci. Instr. \textbf {76},113101 (2005).