Model-independent radiative corrections to M+-/sub l/3 decays

The radiative corrections to first order in α to the three-body semileptonic decays of pseudoscalar mesons, M/sub l/3, are treated in a general fashion, which is suitable for model-independent experimental analysis. Special attention is paid to the energy dependence of the form factors involved. No approximation is made about the smallness of the four-momentum transfer. As an application an expression for the energy spectrum of the charged lepton is derived. The procedure developed in this paper is valid for π/sub e/3, K+-/sub l/3, D+-/sub l/3, or any charged M/sub l/3 decay, l being an electron or a muon, provided hard bremsstrahlung photons are experimentally discriminated