Kaon Radiative Decay K+ -> mu+ nu gamma at CKM at the Fermilab Main Injector

High statistics data for the K+ -> mu+ nu gamma decay can allow the precision determination of the kaon structure dependent form factors and the kaon polarizability. This study is possible at the proposed FNAL CKM experiment. CKM (Charged Kaons at the Main injector) is a decay-in-flight spectrometer with two RICH, and designed to run at the main injector with a high kaon flux. The radiative decay data will be taken complementary to the primary CKM effort to study the rare kaon decay (K to pi nu nubar) for which CKM was primarily designed. We summarize here the underlying physics of K ->mu nu gamma, the experimental status, and how the CKM spectrometer will be adapted for this study.