Infrared End-point Singularities

Abstract

End-point singularities show up in radiative corrections when the whole bremsstrahlung spectrum is integrated over. When multiple photon bremsstrahlung is taken into account through the use of coherent states the infrared terms sum up to an exponential which vanishes at the end-point. Two cases are treated, i) backward scattering of an electron by a static Coulomb potential and (ii) the upper end of the electron spectrum in muon decay.