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 …

A fully analytical description of the allowed β spectrum shape is given in view of ongoing
and planned measurements. Its study forms an invaluable tool in the search for physics …

The 6.8 σ anomaly in excited Be 8 nuclear decays via internal pair creation is fit well by a
new particle interpretation. In a previous analysis, we showed that a 17 MeV protophobic …

The electroweak interaction in the standard model is described by a pure vector-axial-vector
structure, though any Lorentz-invariant component could contribute. In this Letter, we …

The precision of correlation measurements in neutron and nuclear β decay has now
reached the level of about 1% and better. At this level of precision, higher-order corrections …

Using Triumf's neutral atom trap, Trinat, for nuclear β decay, we have measured the β
asymmetry with respect to the initial nuclear spin in K 37 to be A β=-0.5707 (13) syst (13) stat …

In the limit of large nuclear charge, Z≫ 1, or small lepton velocity, β≪ 1, Coulomb
corrections to nuclear beta decay and related processes are enhanced as Z α/β and become …

We report a high-statistics measurement of the L/K orbital electron capture ratio in Be 7
embedded in cryogenic Ta. The thin Ta film formed part of a high-resolution …

The β+ decay of B 8 provides the dominant source of solar neutrinos above 2 MeV.
Consequently, experiments that detect neutrinos from the sun require an accurate …

We report the first precise measurement of a β-recoil correlation from a radioactive noble
gas (He 6) confined via a magneto-optical trap. The measurement is motivated by the search …