We analyze the ${\pi }^0$ photoproduction near threshold on spin- and isospin-zero nuclei within the elementary particle approach. From ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ data, we find that model independent contributions are very small. This makes the analysis of different models quite clear. Thus, while individual excited nuclear states contribute negligibly, the meson exchange correctly describes the data. Measurements of the mass number dependence of the meson-nuclei couplings would test these ideas.

• Received 27 February 1985

DOI:https://doi.org/10.1103/PhysRevC.32.1108