Colloquium: Dr. Jeff Martin
Department of PhysicsThe University of Winnipeg Winnipeg, MB
Bouncing Neutrons and New Physics
Neutrons that have been cooled below 3 mK exhibit a peculiar behavior: they bounce off walls instead of passing right through them! Such neutrons are called ultracold neutrons, and they can be trapped for long periods of time in material, magnetic, and gravitational bottles.
We use ultracold neutrons in experiments to study the fundamental interactions of the neutron very precisely. Examples are experiments searching for a non-zero neutron electric dipole moment, precise measurements of the neutron lifetime, and measurements of the quantization of neutron energy levels in Earth's gravitational field.
New sources of ultracold neutrons are being prepared worldwide to complete these experiments, including one that we're building in Canada (at TRIUMF, in Vancouver). The new sources rely on cryogenic ultracold neutron converter technology that has only been successfully demonstrated in the past 15 years. I will discuss fundamental physics with ultracold neutrons, recent results, and the bright future for this field. Special focus will be given to electric dipole moment experiments, which may shed light on sources of new physics believed to be required to explain the baryon asymmetry of the universe.