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Towards Measuring the Electron Electric Dipole Moment Using Trapped Molecular Ions

TitleTowards Measuring the Electron Electric Dipole Moment Using Trapped Molecular Ions
Publication TypeThesis
Year of Publication2010
AuthorsStutz, RP

Permanent electric dipole moments have been the subject of experimental investigation for the past sixty years, as they entail the breaking of fundamental symmetries and provide a sensitive probe for physics beyond the Standard Model. This thesis describes an experiment aimed at measuring the electron electric dipole moment (eEDM) using trapped molecular ions. The 3Δ1 level of certain diatomic ions are desirable in eEDM searches due to their high polarizability, large eEDM enhancement factor, and relative insensitivity to magnetic fields. Ions allow for simple trapping and long interrogation times, but require a time-varying electric bias field in order to probe the eEDM.

I will discuss the criteria for molecular ions in our experiment and our current candidates. A laser-ablation supersonic-expansion beam source has been developed to create and cool molecular ions. These ions have been loaded into a linear rf Paul trap and alternative photoionization methods for state-selective ion creation have been tested. Various experimental methods for performing the necessary spin resonance measurement are discussed. Sources of both decoherence and systematic errors have been identified and estimated. The experiment described in this thesis should be capable of a factor of 30 improvement on the current limit of the eEDM.