Observation of Semileptonic Decays of Charmed Baryons

Direct electrons are observed in baryon events produced in $e^{+}{e}^{-}$ annihilation at center-of-mass energies above the ${\Lambda }_c{\overline{\Lambda }}_c$ threshold. These events are attributed to charmed-baryon pair production and subsequent ${\Lambda }_c$ semileptonic decay. Various semileptonic branching ratios of the ${\Lambda }_c$ are determined, including $B({\Lambda }_c\to e^{+}X)=(4.5\mathrm{}\pm 1.7)\%$.