A search for neutron Electric Dipole Moment
(pre-preliminary)
Wangzhi Zheng
A search for neutron Electric Dipole Moment (nEDM) will help people to identify new sources of CP violation and T violation. If a non‐zero EDM exists in neutron, neutron will precess under an external electric field. The nEDM experiment will precisely measure the precession frequency of neutron in both electric and magnetic field. The measurement will be performed in two cases, when both fields are parallel and they are anti‐parallel to each other. The nEDM will be deduced by comparing these two cases. Polarized 3He will also be introduced to measure the magnetic field uniformity in order to reduce systematic errors as well as to measure the precession frequency of neutron indirectly by spin‐dependent nuclear reaction between polarized neutron and 3He. A Superconducting QUantum Interference Device (SQUID) will be used in nEDM experiment to monitor the 3He polarization during the injection of 3He into a collection volume at a temperature of ~350 mK before the polarized 3He will be transported to the measurement cell, where the nEDM experiment is performed. Due to a high electric field (50 kV/cm) environment and the lack of a magnetic shielding, it is a challenge for SQUID to work flawlessly. Many technical issues need to be solved before the installation of SQUID into the nEDM experiment.
