Measurement of the $$K^+\rightarrow {\mu ^+}{\nu _{\mu }}{\gamma }$$ decay form factors in the OKA experiment
V. Kravtsov (Institute for Nuclear Research of the Russian Academy of Sciences, Moscow, 117312, Russia); S. Akimenko (NRC “Kurchatov Institute”-IHEP, Protvino, 142281, Russia); A. Artamonov (NRC “Kurchatov Institute”-IHEP, Protvino, 142281, Russia); A. Blik (NRC “Kurchatov Institute”-IHEP, Protvino, 142281, Russia); V. Burtovoy (NRC “Kurchatov Institute”-IHEP, Protvino, 142281, Russia); et al - Show all 39 authors
A precise measurement of the vector and axial-vector form factors difference $$F_V-F_A$$ in the $$K^+\rightarrow {\mu ^+}{\nu _{\mu }}{\gamma }$$ decay is presented. About 95K events of $$K^+\rightarrow {\mu ^+}{\nu _{\mu }}{\gamma }$$ are selected in the OKA experiment. The result is $$F_V-F_A=0.134\pm 0.021(stat)\pm 0.027(syst)$$ . Both errors are smaller than in the previous $$F_V-F_A$$ measurements.