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Department of Physics and Astronomy
University of Mississippi


Event Information:

  • Tue

    Colloquium: Precision Fundamental Symmetry Measurements With Cold Neutrons

    4:00 pmLewis Hall 101

    Jason Fry
    Department of Physics
    University of Virginia

    Precision Fundamental Symmetry Measurements With Cold Neutrons

    The neutron can be used as a powerful tool to study a wide range of phenomena through many disciplines of physics. In particular, cold neutrons are utilized in condensed matter, nuclear, and particle physics with deep connections to cosmology. The free neutron has a slightly larger mass than the proton leading to far reaching implications. How long a free neutron lives determines how the light elements formed in the early universe. The kinematics of neutron decay give us insight into how quarks mix in the weak interaction. Additionally, as a neutral particle, neutrons can penetrate deeply into nucleons to further our understanding of how the strong and weak interaction mix at the smallest scales. In this talk, I will discuss the neutron physics experiments carried out and planned on the Fundamental Neutron Physics Beamline (FNPB) at the Spallation Neutron Source at Oak Ridge National Lab. The NPDGamma experiment, the first experiment on the FNPB, studied the most fundamental process in the Hadronic Weak Interaction (HWI) and the results set the best constraint for future investigation of the HWI. Currently we are commissioning the Nab experiment on FNPB which will make precise measurements of the electron neutrino correlation parameter "a" and the Fierz interference term "b" in unpolarized neutron beta decay. These results will lead to a new, precise, independent determination of the ratio λ = GA/GV that will sensitively test CKM unitarity.