Sharpening low-energy, standard-model tests via correlation coefficients in neutron beta decay.
The correlation coefficients a, A, and B in neutron beta 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 beta decay can be qualitatively bettered.
Gardner
S
S
Department of Physics and Astronomy, University of Kentucky, Lexington, Kentucky 40506-0055, USA. gardner@pa.uky.edu
Zhang
C
C