Searches for the baryon- and lepton-number violating decays $B^0\to {\Lambda }_c^{+}{\ell }^{-}$, $B^{-}\to \Lambda {\ell }^{-}$, and $B^{-}\to \bar{\Lambda }{\ell }^{-}$

Abstract

Searches for $B$ mesons decaying to final states containing a baryon and a lepton are performed, where the baryon is either ${\Lambda }_c$ or $\Lambda$ and the lepton is a muon or an electron. These decays violate both baryon and lepton number and would be a signature of physics beyond the standard model. No significant signal is observed in any of the decay modes, and upper limits in the range $(3.2-520)\times 10^{-8}$ are set on the branching fractions at the 90% confidence level.

10 pages, 14 EPS figures, submitted to PRD-RC