Measurement of B(Λc +→pK-π+)

The {lambda}{sub c}{sup +}{yields}pK{sup -}{pi}{sup +} yield has been measured in a sample of two-jet continuum events containing both a charm tag (''D(bar sign)'') as well as an antiproton (e{sup +}e{sup -}{yields}D(bar sign)p(bar sign)X), with the antiproton in the hemisphere opposite the D(bar sign) (measurement of charge conjugate modes is implicit throughout). Under the hypothesis that such selection criteria tag e{sup +}e{sup -}{yields}D(bar sign)p(bar sign){lambda}{sub c}{sup +}X events, the {lambda}{sub c}{sup +}{yields}pK{sup -}{pi}{sup +} branching fraction can be determined by measuring the pK{sup -}{pi}{sup +} yield in the same hemisphere as the antiprotons in our D(bar sign)p(bar sign)X sample. Three types of D(bar sign) charm tags are used, {pi}{sub soft}{sup -} (from D{sup *-}{yields}D(bar sign){sup 0}{pi}{sub soft}{sup -}), electrons (from D(bar sign){yields}Xe{sup -}{nu}), and fully reconstructed D(bar sign){sup 0}{yields}K{sup +}{pi}{sup -} or D{sup -}{yields}K{sup +}{pi}{sup -}{pi}{sup -} or D{sub s}{sup -}{yields}{phi}{pi}{sup -}. Combining our results obtained from the three independent charm tags, we obtain B({lambda}{sub c}{sup +}{yields}pK{sup -}{pi}{sup +})=(5.0{+-}0.5{+-}1.2)%. (c) 2000 The American Physical Society.