Radiative Corrections to K^0_{l3} Decays
We calculate the long-distance radiative corrections δ^e_{LD} and δ^μ_{LD} to the K^0 -> π^- e^+ ν_e and the K^0 -> pi^- μ^+ ν_μ decay rates. This analysis includes contributions to the long-distance radiative corrections from outside the kinematically-allowed three-body Dalitz region and tests the sensitivity of the radiative corrections to the hadronic K-pi form factors. A program, KLOR, was written to numerically evaluate the radiative corrections and to generate Monte Carlo events for experimental acceptance studies. The K^0_{e3} and the K^0_{μ3} long-distance radiative correction parameters are determined to be (1.3 +/- 0.3)% and (1.9 +/- 0.3)%, respectively. We also present predictions for the fraction of radiative K^0_{l3} events satisfying various requirements on final-state photon kinematics.