Parity Nonconservation in ElasticpαScattering and the Determination of the Weak Meson-Nucleon Coupling Constants

Parity nonconservation has been studied in elastic $p\alpha$ scattering at 46 MeV with longitudinally polarized protons. The longitudinal analyzing power averaged over the range of laboratory scattering angles of roughly 30° to 60° is found to be $A_z=(-3.3\mathrm{}\pm 0.9)\times {10}^{-7\mathrm{}}$. This result and measurements in other light nuclear systems are used to determine weak meson-nucleon coupling constants.