A Measurement of the Branching Ratio (KL0→πμν)(KL0→πeν)

Abstract

We present the results of a study of ${K_L}^0$ decays observed in the CERN 1.1-${\mathrm{m}}^3$ heavyliquid bubble chamber. About 75 000 frames were scanned, and yielded some 7500 examples of isolated ${K_L}^0$ decays to charged particles. Based on a sample of 4000 events in a restricted fiducial region, the following branching ratios were found: $\frac{N({K_L}^0\to {\pi }^{\pm }{\mu }^{\mp }\nu )}{N({K_L}^0\to {\pi }^{\pm }{e}^{\mp }\nu )}=0.648\mathrm{}\pm 0.030,$ $\frac{N({K_L}^0\to {\pi }^{+}{\pi }^{-}{\pi }^0)}{N({K_L}^0\to \mathrm{all}\mathrm{charged})}=0.157\mathrm{}\pm \mathrm{0.010.}$