Radiative Corrections to K_l2 decays

We consider $K_{l2}$ decays to the order $O(\alpha)$. We perform a matching calculation, using a specific model with vector meson dominance in the long distance part and the parton model in the short distance part. By considering the dependence on the matching scale and on the hadronic parameters, and by comparing with the leading model independent predictions, we scrutinize the model dependence of the results.