Hyperon Non-leptonic Weak Decays in the Chiral Perturbation Theory II
  Hyperon non-leptonic weak decay amplitudes are studied in the chiral perturbation theory. The weak interaction vertices caused by the four quark operators are substituted by the products of the hadronic currents and by the phenomenologically introduced weak Hamiltonian of hadron operators. Our study suggests the improvement of the theoretical prediction for the weak decay amplitudes. 
K. Takayama and M. Oka