Effect of the Failure of Isotopic Spin Conservation on the Pion-Nucleon S Waves

The charge-dependent effects of the π^--π⁰ mass difference, the Coulomb interaction, and the π^-+p→γ+n radiative transition are calculated phenomenologically using a charge-independent potential model for the pion-nucleon nuclear S-state interaction. It is found that the charge-exchange S-wave-scattering is little affected but that the transition rate for a bound π^- meson (Panofsky effect) is suppressed about 10%, removing the discrepancy between the difference in scattering lengths as calculated from scattering and from the Panofsky effect. However, it is also found that there can be 25% corrections to the π^- elastic scattering amplitude of either sign, making the precise analysis of low-energy π^- elastic scattering experiments difficult.