Measurement of the Branching RatioΓ(KL0→π±μ∓ν)Γ(KL0→π±e∓ν)

Abstract

We present the results of a measurement of the $\frac{{{K}_{\ensuremath{\mu}3}}^{0}}{{{K}_{e3}}^{0}}$ branching ratio, obtained from a study of ${{K}_{L}}^{0}$ decays using a multiwire-proportional-chamber spectrometer. The ${{K}_{\ensuremath{\mu}3}}^{0}$ and ${{K}_{e3}}^{0}$ events were separated by muon range counters, and ${{K}_{\ensuremath{\pi}3}}^{0}$ events were separated from the ${{K}_{e3}}^{0}$ sample kinematically. From a sample of approximately 10000 ${{K}_{\ensuremath{\mu}3}}^{0}$ and ${{K}_{e3}}^{0}$ events, we obtain a value of the branching ratio $\frac{\ensuremath{\Gamma}({{K}_{\ensuremath{\mu}3}}^{0})}{\ensuremath{\Gamma}({{K}_{e3}}^{0})}=0.662\ifmmode\pm\else\textpm\fi{}0.037$.