The sign of the K - -nucleus potential

Abstract

The small-angle elastic scattering of K - mesons by the nuclei of photographic plates has been measured in the energy interval 106 to 144 MeV. The experimental reaction cross-section and elastic differential cross-section are compared with cross-sections obtained from the optical model of the nucleus by exact numerical solution of the Klein-Gordon equation at 125 MeV. If the potential radius (Woods & Saxon 1954) is r 0 = 1.07 A ½ x 10 -13 cm, the most probable value of the real part of the potential is U = − 30 MeV. For r 0 = l.20 A ½ x 10 -13 cm, U = − 16 MeV. The experimental values of U appear to resolve the sign ambiguity in the real parts of the K − -nucleon s - wave scattering lengths.