Effective-Hamiltonian Approach to Hyperon Beta Decay

Our approach to hyperon $\beta$ decay is to restrict the theory, from the beginning, to the first order in the velocity of the recoil nucleon. The resulting effective Hamiltonian leads to an approximation which displays the physical content of the theory more explicitly than the exact expressions, through a simple form already familiar from neutron $\beta$ decay. Assuming the current-current form of the weak interaction and a $V-A$ lepton current, the most general hadron current is used, and the weak magnetism and pseudotensor terms are retained. We obtain correlation coefficients for the decay angular distribution of polarized hyperons which are in close agreement with the exact theory.