Coulomb Corrections toτ-Meson Decay

Abstract

The effect of the Coulomb interaction on the energy and angular distribution of the final-state pions in $\tau$-meson decay is calculated by perturbation theory. The result indicates a shift of the order of magnitude of 3% from large to small energies and angles. The result differs in some quantitative aspects from those previously derived by treating some or all of the pions classically. In particular the energy dependence of the correction disappears at low energies.