Most of the available data on the elastic scattering of pions by nuclei between 14 and 80 MeV are analyzed with a complex local optical potential which is parametrized by a bias-free Fourier-Bessel series, and is used as a means of extracting as much information from the data as possible without the explicit use of a model for the interaction. A typical shape of a negative real potential at large radii with a positive one at smaller radii is obtained and a systematic dependence on energy, charge of the pion, and isospin of the target is observed. The Kisslinger potential is shown to reproduce all these systematics, whereas the Laplacian potential fails to do so. Some results for energies of up to 230 MeV are also analyzed. The dependence of reaction cross sections on the real potential is discussed.

NUCLEAR REACTIONS Pion-nucleus "model-independent" optical potentials 14-230 MeV on various targets.

• Received 16 May 1983

DOI:https://doi.org/10.1103/PhysRevC.28.1264