Neutron beta decay provides a way to test the standard model without the complicating effects of nuclear structure. I will discuss the status of two neutron decay experiments on the fundamental physics beamline at NIST. The first experiment, called aCORN (‘a’ CORellation in Neutron decay), measures the beta-neutrino correlation commonly parameterized by the little ‘a’ coefficient. This experiment uses geometry and kinematics to turn the beta-neutrino angular distribution into a counting asymmetry. aCORN is in the last stages of analysis. I will also touch on a second experiment, with the imaginative name of BL3 (Beam Lifetime 3), which will measure the neutron lifetime. There is currently a discrepancy between two techniques for measuring the lifetime. This proposed experiment will explore the systematic errors in the beam technique to help resolve this discrepancy.

Argonne Physics Division Colloquium Schedule