NEGATIVE PION SCATTERING AND THE DISPERSION RELATIONS

The forward scattering dispersion relations have been used to analyze the scattering of negative pions on protons. Since the results werc a poor fit, the integrals S- over total cross sections that appear in the dispersion relation were recalculated. The results proved to bc very sensitive to the chosen energy dependence of the total cross section, due to the strong dependence of the integral on the derivative of the cross section with respect to energy. Two curves of the cross section versus energy are presented which correspond adequately to the data. One of them gives forward scattering similar to previous results, the other does not significantly contradict the dispersion relations or charge independence. The possibility of distinguishing between the curves by re- examining the 100-Mev region is suggested. (M.H.R.)