Nuclear Physics B79 (1974) 168-188. North-Holland Publishing Company VECTOR-MESON DOMINANCE IN THE HADRONIC AND RADIATIVE WEAK NON-LEPTONIC DECAYS OF HYPERONS K. GAVROGLU* and H.P.W. GOTTLIEB** Theoretical Physics Department, Imperial College, London SW7, England Received 7 January 1974 (Revised 16 May 1974) Abstract: The radiative pionic hyperon decays B -~ B'Tr3~ are investigated in the framework of vector-meson dominance. K*, p and photon poles are used in association with various models for vertices to obtain alternative descriptions to the usual bremsstrahlung and current algebra approaches. A phenomenological model for the B ~ B'7 decays is included in the same spirit. 1. Introduction The fundamental problem in the strangeness-changing non-leptonic decays B ~ B'Tr, apart from the explanation of the AI = 1 rule, is to fit the s-wave, parity- violating (pv), and p-wave, parity-conserving (pc), amplitudes simultaneously [ I ]. Thus a successful model has to describe both parts A (pv) and B (pc) in the matrix element defined by T=-(B'n IHw [B) (1.1a) = ~(p') [A + 75B ] u(p), (1 .lb) where H w is the weak interaction Hamiltonian and p, p' are the momenta of the baryons B and B' respectively. For the radiative decays B -+ B'3,, the amplitude is defined by T=--(B'TLHwEIB) = ~(p') e[C + D3,5] oUVqu%u(p), (1.2a) (1.2b) * Present address: Department of Philosophy, State University of New York at Stony Brook, Long Island, New York 11790, U.S.A. ** Present address: Department of Mathematical Physics, University of Adelaide, Australia 5001