Abstract:

The magnetic dipole interaction played a central role in the development of QED, and continued that role for the standard model. The muon anomalous magnetic moment has served as a benchmark for models of new physics, and the present experimental value is larger than the standard-model value by more than three standard deviations. The electric dipole moment (EDM) violates parity (P) and time-reversal (T) symmetries, and in the context of the CPT theorem, the combination of charge conjugation and parity (CP). Since a new source of CP violation outside of that observed in the K and B meson systems is needed to help explain the baryon asymmetry of the universe, searches for EDMs are being carried out worldwide on a number of systems. The standard-model value of the EDM is immeasurably small, so any evidence for an EDM would signify the observation of new physics. This talk will provide an overview of the theory of dipole moments along with the experiments, with an emphasis on the new muon (g-2) experiment at Fermilab.