π-Meson production by photons at He³ in current-algebra model

Abstract

In an analysis of the photoproduction ofπ-mesons at He³ in the current-algebra model with hardπ-mesons, the amplitude for the process is derived with the help of the Ward identity, which follows from the hypothesis of the partial conservation of axial-vector current and current algebra. Only theπ-meson and the He³ and H³ nuclei are taken into account in the sums over intermediate states. The contact terms are important for an explanation of the experimental data. The differential cross sections are calculated for the photoproduction ofπ ⁺-mesons at He³; they agree satisfactorily with the experimental data for low energies (E_γ<240 MeV) and for low-momentum transfer (¦t¦<2.5 F⁻²).