An experiment to measure λ=GA/GV from a combination of angular correlation coefficients in the beta decay of polarized neutrons

A technique is described which allows us to measure the ratio λ=GA/GV of the weak axial-vector and vector coupling constants in neutron decay without any measurement of the neutron beam polarization. λ is determined from a combination of the parity-odd angular correlations σ→·p→e and σ→·p→ν between the neutron spin σ→ and the electron momentum p→e and the anti-neutrino momentum p→ν, respectively, both of which are measured in a single experiment using the same neutron beam. A description of the experiment and the results of the first run at the cold neutron beam facility at the Institut Laue–Langevin are presented.