Radiative Corrections toK→eνandK→μνDecays

The radiative corrections to the ratio of the $K\to e\nu$ rates to the $K\to \mu \nu$ rates are calculated for an experiment where photon counters are used to help discriminate against the $K_{e3\mathrm{}}$ background. This is in contrast to the previously calculated case where all photon energies are included in the rate. The theoretical advantage of including only the low-energy photons is emphasized in this note.