First Measurement of the Absolute Branching Fraction of $\Lambda \to p{\mu }^{-}{\bar{\nu }}_{\mu }$

M. Ablikim, M. N. Achasov, P. Adlarson +504

The absolute branching fraction of $\Lambda \to p{\mu }^{-}{\bar{\nu }}_{\mu }$ is reported for the first time based on an $e^{+}{e}^{-}$ annihilation sample of ten billion $J/\psi$ events collected with the BESII…