Phenomenological Relationships between Photomeson Production and Meson-Nucleon Scattering

Photomeson production is studied on the basis of the hypothesis of charge independence combined with the suggestion from meson theory that the meson-nucleon state of angular momentum and isotopic angular momentum equal to $\frac{3}{2}$ is one of strong, resonant interaction. Reasonable agreement with experiment is obtained, both as to the energy dependence of the cross sections and as to their ratios. Similar considerations lead to a possible explanation for the angular dependence of ${\pi }^{+}$ mesons produced in $p-p$ collisions.