ACME: Advanced Cold Molecule Electron Electric Dipole Moment Search

Yale University, New Haven CT

Investigators

Abstract

The Advanced Cold Molecule Electric Dipole Moment Search (ACME) is a new collaborative effort to detect the electric dipole moment (EDM) of the electron. The most fundamental of physics theories, the Standard Model of particle physics, predicts an extremely small electron EDM, while essentially all proposed extensions to the Standard Model predict an electron EDM that is within the projected sensitivity for this experiment. The ThO molecule that ACME will use provides in one species all of the advantages identified by past molecular EDM studies, with the added benefit of a higher internal electric field which will further increase the sensitivity of the experiment. Moreover, the prototype ThO molecular beam source that ACME is developing, using laser ablation and cryogenic buffer gas cooling, already demonstrates the possibility of a usable flux of molecules that is a thousand times that of previous experiments. The initial ACME goal is to measure the electron EDM with a sensitivity that greatly exceeds the current limit. Many students and postdocs will learn their craft working on this experiment, and many of the techniques developed will have general application to precision measurements. There will be a broad impact on physics, whatever the ACME result. The lack of an electron EDM at the attainable precision would eliminate the most studied and motivated extensions to the Standard Model. The discovery of an electron EDM would be one of the great breakthroughs in physics, signifying the long anticipated breakdown of the Standard Model of particle physics, and heralding a new understanding of the imbalance between antimatter and matter in the universe