Measurement of B(Λc+→pK-π+)

The Λc⁺→pK^-π⁺ yield has been measured in a sample of two-jet continuum events containing both a charm tag (``D̄'') as well as an antiproton (e⁺e^-→D̄p̄X), with the antiproton in the hemisphere opposite the D̄ (measurement of charge conjugate modes is implicit throughout). Under the hypothesis that such selection criteria tag e⁺e^-→D̄p̄Λc⁺X events, the Λc⁺→pK^-π⁺ branching fraction can be determined by measuring the pK^-π⁺ yield in the same hemisphere as the antiprotons in our D̄p̄X sample. Three types of D̄ charm tags are used, πsoft^- (from D^*-→D⁰πsoft^-), electrons (from D̄→Xe^-ν), and fully reconstructed D⁰→K⁺π^- or D^-→K⁺π^-π^- or Dₛ^-→φπ^-. Combining our results obtained from the three independent charm tags, we obtain B(Λc⁺→pK^-π⁺)=(5.0±0.5±1.2)%.