First Observation of Inclusive $B$ Decays to the Charmed Strange Baryons $\Xi_{c}^{0}$ and $\Xi_{c}^{+}$

Using data collected in the region of the Υ(4 S ) resonance with the CLEO II detector operating at the Cornell Electron Storage Ring (CESR), we present the first observation of B mesons decaying into the charmed strange baryons Ξ 0 c and Ξ + c . We find 79 ± 27 Ξ 0 c and 125 ± 28 Ξ + c candidates from B decays, leading to product branching fractions of B ( B → Ξ 0 c X ) B (Ξ 0 c → Ξ − π + ) = (0 . 144 ± 0 . 048 ± 0 . 021) × 10 − 3 and B ( B → Ξ + c X ) B (Ξ + c → Ξ − π + π + ) = (0 . 453 ± 0 . 096 + 0 . 085 − 0 . 065 ) × 10 − 3 .