CONSEQUENCES OF MODIFIED HYPOTHESIS OF PARTIALLY CONSERVED AXIAL-VECTOR CURRENT IN PHOTOPION PRODUCTION

The photopion production process γ+N→N+π is studied in connection with the hypothesis of partially conserved axial-vector current, which is suitably generalized to deal with electromagnetic interactions. Some interesting relations are derived between the nucleon magnetic moments and certain analytically continued isotopic-spin components of the photopion amplitude. It is found that one of these relations contains an amplitude which is related to an electromagnetic transition involving only the isoscalar part of the photon. This amplitude is calculated from the ρ-dominance model in the crossed photoproduction channel γ+π→N+N̄. With this model, the ρ-π-γ vertex is calculated in terms of the ρ-γ vertex, the renormalized π-N coupling constant, and the ratio of isoscalar and isovector nucleon magnetic moments. The present analysis gives a numerical value which is considerably smaller than those estimated previously by independent methods. © 1968 The American Physical Society.