Department of Physics, NCU
Searching for the Electric Dipole Moment of the Neutron to Explain the Matter-Antimatter Imbalance of the Universe
Prof. Chen-Yu Liu
Department of Physics,
Indiana University Bloomington
Time: 2019/06/17 Monday at 14:00
Location: S4-625
Abstract:
Searches for the neutron electric dipole moment (nEDM) began in 1951 and, up to the present, no evidence for an nEDM has been found. The persistent effort in the community to search for the nEDM is currently driven by the desire to explain the over-abundance of matter relative to anti-matter in the universe. The dynamical origin of this imbalance, or baryogenesis, is thought to have occurred a few picoseconds after the Big Bang, driven by combined Charge Conjugation-Parity (CP) symmetry violating processes beyond those predicted by the Standard Model of particle physics. The neutron is the simplest neutral hadronic system which lives long enough on which to conduct these symmetry tests. A non-zero nEDM would violate both P and Time-reversal (T) symmetries. In many scenarios, successful baryogenesis leads to strict lower bounds on the nEDM on the order of our target sensitivity of 3E-27 e-cm. To achieve this sensitivity, several efforts are underway in USA and Europe. In this talk, I will review the theoretical motivation for EDM searches and describe the experimental techniques. The latter include high-density ultracold neutron (UCN) sources, state-of-the-art magnetic shielding, novel magnetic field configurations, and sensitive magnetometry (both external and co-habitating) to control systematic effects. I will focus on one particular initiative at the Los Alamos National Laboratory, where we plan to improve the EDM sensitivity by an order of magnitude within a decade.