From a sample of 332000 $B\overline{B}$ pairs produced in $e^{+}{e}^{-}$ annihilations at the $\Upsilon \mathrm{}\left(4S\right)\mathrm{}$ resonance we derive upper limits for the branching fractions for the decays $B^{-}\to p\overline{p}{\pi }^{-}$ and ${\overline{B}}^0\to p\overline{p}{\pi }^{+}{\pi }^{-}$ in several final-state momentum configurations. The results do not confirm recently reported observations of charmless $B$ decays.

• Received 3 October 1988

DOI:https://doi.org/10.1103/PhysRevLett.62.8