Total Cross Section for Charge Exchange Scattering ofπ−Mesons by Hydrogen at 42, 30, and 20 Mev

Abstract

A measurement of the total cross section for the reaction $p({\pi }^{-}, {\pi }^0)n$ has been made at three energies using polyethylene and carbon targets in a difference experiment. The values obtained for the cross sections are $\sigma \left(42\mathrm{} \mathrm{Mev}\right)=6.9\mathrm{}\pm 1.2$ mb; $\sigma \left(30\mathrm{} \mathrm{Mev}\right)=5.7\mathrm{}\pm 0.9$ mb; and $\sigma \left(20\mathrm{} \mathrm{Mev}\right)=5.0\mathrm{}\pm 0.8$ mb. The results are analyzed under the assumption of charge independence in an attempt to determine the energy dependence of the $S$-wave phase shifts.