A tabletop-scale probe for TeV-scale physics: new limit on the electron electric dipole moment from the ACME experiment

All CP-violating effects observed to date are consistent with a single origin in the Standard Model (SM)--the complex phase in the CKM matrix that describes quark flavor-changing currents. However, additional sources of CP violation, associated with new physics above the electroweak scale, are needed to explain the observed cosmological baryon asymmetry. In the presence of CP-violation, elementary particles such as the electron can have an electric dipole moment (EDM) along their spin axis. The SM prediction for the electron EDM is nonzero, but too small to detect. By contrast, many plausible extensions to the SM naturally should lead to EDMs that are within experimental reach. Our ACME experiment uses methods of atomic and molecular physics to detect the electron EDM, and we recently completed the most sensitive search for this quantity. Our result is consistent with zero, but sets a limit ten times smaller than in any previous work. Remarkably, the result of this tabletop-scale experiment sets strong constraints on theories of physics beyond the SM. In many specific models, the ACME result probes physics associated with new particles whose mass is well above the scales studied directly at colliders. This talk will describe the new ACME result and some of its implications.