Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268


Wed., April 25, 2007, at 11:00 a.m. (refreshments at 10:40 a.m.)

Measuring the Neutron Lifetime Using Magnetically Trapped Ultracold Neutrons

Pieter Mumm, National Institute of Standards and Technology, Gaithersburg, MD
Building 6008 Conference Room

Free neutrons are unstable and decay with a lifetime of approximately 885 s. This lifetime influences the predictions of Big Bang Nucleosynthesis and is important in tests of the Standard Model of particle physics. New measurements of the neutron lifetime, utilizing novel techniques, are especially important today as the most recently reported result differs from the world average by six standard deviations. A new approach using magnetically trapped ultracold neutrons produced by down-scattering in ultra-pure helium has been demonstrated at NIST. I will report the recent progress made in upgrading this experiment with a larger deeper trap as well as the prospects for future runs at NIST and the SNS.

Host: Geoffrey Greene (574-8435)