The status of tests of the standard electroweak model and of searches for new physics in
allowed nuclear β decay and neutron decay is reviewed including both theoretical and …

We report an improved measurement of the free neutron lifetime τ n using the UCN τ
apparatus at the Los Alamos Neutron Science Center. We count a total of approximately 38× …

Background: The neutron β-decay asymmetry parameter A 0 defines the angular correlation
between the spin of the neutron and the momentum of the emitted electron. Values for A 0 …

A new measurement of the neutron β-decay asymmetry A 0 has been carried out by the
UCNA Collaboration using polarized ultracold neutrons (UCNs) from the solid deuterium …

We present a detailed report of a measurement of the neutron β-asymmetry parameter A 0,
the parity-violating angular correlation between the neutron spin and the decay electron …

It has been proposed recently that a previously unobserved neutron decay branch to a dark
matter particle (χ) could account for the discrepancy in the neutron lifetime observed in …

We present a review of the motivation and results of recent experiments which utilize
ultracold neutrons for measurements of neutron beta decay. Because these experiments …

The UCN τ experiment is designed to measure the lifetime τ n of the free neutron by trapping
ultracold neutrons (UCN) in a magneto-gravitational trap. An asymmetric bowl-shaped …

We describe a detection system designed for precise measurements of angular correlations
in neutron β decay. The system is based on thick, large area, highly segmented silicon …

We report on the evaluation of commercial electroless nickel phosphorus (NiP) coatings for
ultracold neutron (UCN) transport and storage. The material potential of 50 μ m thick NiP …