The search for a non-zero value for the electric dipole moment of the neutron has a long history. If the neutron has an EDM it would be an explicit example of time reversal invariance violation. We know time reversal invariance is violated at a very small level in the Standard Model; this level does not lead to a nEDM that would be observable. However, almost any extension to the Standard Model predicts a nEDM that is only one to two orders of magnitude below the current limit. Therefore, searches for a non-zero nEDM are among the most important experiments in looking for extensions to the Standard Model.
Bates scientists and engineers are collaborating with others to implement an experiment at the Spallation Neutron Source at Oak Ridge National Laboratory in Tennessee to search for a non-zero nEDM. This experiment involves bringing polarized neutrons and polarized 3He atoms into a bath of superfluid 4He. There are many significant technical challenges, and the expertise at Bates is critical to addressing these challenges. Bates is involved in the overall cryogenic engineering, testing and improving the polarized 3He atomic beam source, developing the 3He services, and designing the polarized neutron beam line. It is anticipated that Bates will play an important role in this experiment through its data-taking during the next decade.