Observation of exclusive B decays to final states containing a charmed baryon

Abstract

Using data collected in the region of the Upsilon(4S) resonance with the CLEO-II detector, we report on the first observation of exclusive decays of the B meson to final states with a charmed baryon. We have measured the branching fractions B(B- --> Lambda(c)(+)(p) over bar pi(-)) = (0.62(-0.20)(+0.23) +/- 0.11 +/- 0.10) X 10(-3) and B((B) over bar(0) --> Lambda(c)(+)(p) over bar pi(+)pi(-)) = (1.33(-0.42)(+0.46) +/- 0.31 +/- 0.21) X 10(-3), where the first error is statistical, the second is systematic, and the third is due to uncertainty in the Lambda(c)(+) branching fractions. In addition, we report upper limits for final states of the form (B) over bar --> Lambda(c)(+)(p) over bar(n pi) and Lambda(c)(+)(p) over bar(n pi)pi(0), where (n pi) denotes up to four charged pions. [S0031-9007(97)04176-8].