A phenomenological model is used to obtain cross sections for pions elastically scattered from ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. The model wave function consists of a diffuse hole cut out of a plane wave and a focus term. Five parameters are varied to fit data. Good fits are obtained. The two parameters that describe the region in which absorption takes place are consistent with the effective radius model of Silbar and Sternheim.

NUCLEAR REACTIONS ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\pi ,\pi )$, $E=120-230\mathrm{}$ MeV; ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}(\pi ,\pi )$, $E=160-240\mathrm{}$ MeV; ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}(\pi ,\pi )$, $E=205, 215$ MeV; calculated $\sigma \left(\theta \right)$: Absorption model with focus.

• Received 9 September 1975

DOI:https://doi.org/10.1103/PhysRevC.13.283