Paul Hamilton

The discovery of an electric dipole moment (EDM) of a fundamental particle would provide evidence for physics beyond the Standard Model. Many popular extensions to the Standard Model, such as supersymmetry, predict electron electric dipole moments (eEDMs) within a few orders of magnitude of the current experimental limit. The PbO* experiment uses several unique characteristics of the diatomic molecule lead oxide, that make it a particularly sensitive probe for detecting an eEDM. The valence electrons in PbO experience an effective intramolecular electric field of > 1010 V cm -1 which greatly enhances the energy shift due to an eEDM. Because PbO is chemically stable, unlike many other molecules used in EDM searches, it can be used in a high temperature vapor cell. The large densities in the vapor cell give the PbO* experiment a high statistical sensitivity. In this thesis we will discuss improvements to both the apparatus and the experimental methods that have increased the statistical sensitivity to the point that a competitive limit on the eEDM may be feasible in the near future. Although the eEDM sensitivity was not high enough to place a new eEDM limit, a preliminary measurement was made that placed stringent limits on possible systematic effects. Finally we conclude with a proposed second generation of the experiment based on a microwave absorption measurement. A preliminary analysis suggests the second generation experiment could have sensitivity a few orders of magnitude higher than the current experiment. In the course of investigating this new method, we found several applications in the current experiment. In particular microwave absorption measurements of the PbO vapor pressure and the population transfer of PbO during laser excitation helped to explain the lower sensitivity of the experiment in the past.