Monday, 04 November, 2013
The Beta Decay of the Neutron
Dr. Geoff Greene, UT Department of Physics and Astronomy
While neutrons within nuclei may be stable, the free neutron is unstable against beta decay and has a mean lifetime of ~15min. Free neutron beta decay is a rather simple nuclear process that is uncomplicated by the many the many body effects that are present in the decay of heavy nuclei. As a result, it can be understood in terms of rather simple fundamental weak interaction theory. As the "prototype" for all nuclear beta decays, the free neutron lifetime is a fundamental parameter whose value is important not only in nuclear physics, but also in astrophysics, cosmology, and particle physics. I will give an introduction to the theory of weak nuclear decay and discuss the importance of the neutron lifetime as a parameter in the Big Bang. A discussion of the experimental strategies for the measurement of the neutron lifetime will be given and I will present a new result recently obtained by the University of Tennessee Group at NIST Cold Neutron Research Facility in Gaithersburg Md.