Radiative Correction toKl3Decay

We study the radiative corrections to $K_{l3\mathrm{}}$ decay, assuming that the strong interactions introduce a natural cutoff for the electromagnetic interactions of the hadrons. We take the strong interactions into account by the electromagnetic form factors of the hadrons, for which we assume the vector-meson-dominance model. The radiative corrections are found to be large for some energy configurations, but the correction to the $K_{e3\mathrm{}}$ decay rate is about -2%. This is larger than the -0.45% value previously estimated by Ginsberg. The correction to the $K_{\mu 3}$ decay rate is about -0.4%, and the correction to the polarization of the muon is about -1%.