Theoretical Calculations of the Scattering ofπ−Mesons by Complex Nuclei

Abstract

The angular distributions of 80-Mev negative pions elastically scattered from Li, C, and Al have been analyzed on the basis of optical models by using I.B.M.-650 computers. It was not possible to fit the data with the usual $V_1+i{V}_2$ type model having either a square or diffuse edge and $V_1$ and $i{V}_2$ proportional to the nuclear density. A Kisslinger-type model, which takes better account of the $p$-wave nature of the basic $\pi$-nucleon scattering process, was also used with a modification to avoid a physically unreasonable behavior of the effective interaction. Using $r_0=1.08\mathrm{}$ and a diffuseness parameter $a=0.25\mathrm{}$ in a Saxon-type density distribution, good agreement with experimental data was obtained.