New physics beyond the Standard Model: The small CP violation contained in the Standard Model is insufficient to account for the baryon/antibaryon asymmetry in the universe [Sakharov; 1967]. New sources of CP violation are provided by extensions to the Standard Model. They contain CP-violating phases that couple directly to leptons and from which a large electron electric dipole moment (EDM) may be generated. Observation of an electron EDM would be proof of a Standard Model extension because the Standard Model only allows an electron EDM of less than 10{sup}(-57) C-m (S.I. units; 1 C-m = 1.6 × 10{sup}(-21) e-cm). A null result, however, constrains models and improving the limit tightens constraints, further restricting the models. Any discovered new source of CP-violation not contained in the Standard Model will immediately lead to the question "How strongly does it couple to leptons?" The electron EDM experiment is the experiment that can best answer that question - better than any high energy physics experiment: the electron is stable and it can be precisely probed inside an atom. And the attractiveness of an electron EDM experiments using atoms is that it is sensitive only to a CP violating coupling to leptons - there is no existing effect to be subtracted out.
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