Branching Ratio Measurement of the decay K_L -> e+ e- mu+ mu-

Alavi-Harati

We have collected a 43 event sample of the decay $K_L\to e^{+}{e}^{-}{\mu }^{+}{\mu }^{-}$ with negligible backgrounds and measured its branching ratio to be $(2.62\pm 0.40\pm 0.17)\times 10^{-9}$.…