Time Reversal in Neutron Beta Decay---The emiT Experiment

Session FP - Poster Session III.
POSTER session, Friday afternoon, May 17
Atrium, Chemistry Building

[FP.75] Time Reversal in Neutron Beta Decay---The emiT Experiment

T.D. Steiger, S.R. Elliott, R.G.H. Robertson, J.F. Wilkerson (University of Washington), J. Anaya, T.J. Bowles, G.L. Greene, W.A. Teasdale (Los Alamos National Laboratory), M.S. Dewey, D. Gilliam, J.S. Nico, A.K. Thompson, F.E. Wietfeldt (National Institute of Standards and Technology), S.J. Freedman, B.K. Fujikawa, L.J. Lising, E.G. Wasserman (University of California - Berkeley and Lawrence Berkeley National Laboratory), K.P. Coulter, T.E. Chupp, S.R. Hwang (University of Michigan - Ann Arbor), A. Garcia (University of Notre Dame)

The theory of neutron beta decay provides for the possibility of a violation of time-reversal (T) invariance due to the presence of a manifestly T-odd term. This term is a triple correlation involving the neutron spin and the momenta of the electron and neutrino decay products. The degree of correlation (usually denoted by the coefficient D) may be measured using a beam of cold, polarized neutrons and detecting beta-decay electrons in coincidence with recoil protons. The emiT experiment will improve on previous neutron-based measurements of D by employing PIN diode proton detectors in an octagonal detector array at the Cold Neutron Research Facility, NIST. The expected sensitivity to D is 3 \times 10^-4, which may permit restrictions to be placed on several extensions to the Standard Model that allow values of D near 10^-3. The detector system is currently nearing completion and preliminary runs will be made this summer at NIST.

Part F of program listing