Sharpening Low-Energy, Standard-Model Tests via Correlation Coefficients in Neutron β Decay

The correlation coefficients a, A, and B in neutron β decay are proportional to the ratio of the axial-vector- to-vector weak coupling constants, gA/gV , to leading recoil order. With the advent of the next generation of neutron-decay experiments, the recoil-order corrections to these expressions become experimentally accessible, admitting a plurality of standard model (SM) tests. The measurement of both a and A, e.g., allows one to test the conserved-vector-current (CVC) hypothesis and to search for second-class currents (SCC) independently. The anticipated precision of these measurements suggests that the bounds on CVC violation and SCC from studies of nuclear β decay can be qualitatively bettered