INT$${}^{{-}}$$ Contribution to Form Factors of $${K^{+}\to\mu^{+}\nu_{\mu}\gamma}$$ Decay in OKA Experiment

Abstract

Abstract A new precise measurement of the vector and axial-vector form factor difference $$F_{V}-F_{A}$$ in the $$K^{+}\to\mu^{+}\nu_{\mu}\gamma$$ decay is presented. About 144 K events of $$K^{+}\to\mu^{+}\nu_{\mu}\gamma$$ are selected in the OKA experiment. The result is $$F_{V}-F_{A}=0.135$$$$\pm$$ 0.017(stat) $$\pm$$ 0.024(syst). The number of events is about 1.5 times higher and both errors are smaller than last published OKA result. The presented result is considered as preliminary.