The Physics & Astronomy Colloquium Series presents Ricardo Alarcon of Arizona State University, discussing "Search for the Electric Dipole Moment of the Neutron" on March 6.

Abstact: The electric dipole moment (EDM) of an elementary fermion violates both parity (P) and time‑reversal (T) symmetries, and by the CPT theorem a nonzero EDM therefore signals violation of CP and T symmetries. A neutron EDM (nEDM) at the level predicted by Standard Model (SM) calculations, d_n ~ 10⁻³² e⋅cm, is far below the current experimental upper limit of d_n < 1.8 × 10⁻²⁶ e⋅cm, so any observation within foreseeable experimental sensitivity would constitute unambiguous evidence for physics beyond the SM. Such a signal would also satisfy one of the Sakharov conditions required to explain the matter–antimatter asymmetry of the universe. New nEDM experiments worldwide are targeting sensitivities up to an order of magnitude beyond the present limit. In the United States there is a single experiment, located at Los Alamos National Laboratory, which employs ultra‑cold neutrons, and a precision nuclear magnetic resonance technique based on Ramsey’s separated‑oscillatory‑field method to measure the neutron spin‑precession frequency relative to an external clock.

This project is now at an advanced stage, and I will present a status report on the experiment and its current sensitivity.