Search for $\mathit{B}\to \mathit{\ell }{\overline{\nu }}_{\ell }$

We search for the decays $B^{-}\to {\ell }^{-}{\overline{\nu }}_{\ell }$ in a sample of $2.2\times {10}^6$ charged $B$ decays using the CLEO detector. We see no evidence for a signal in any channel and set upper limits on the branching fractions of $B(B^{-}\to {\tau }^{-}{\overline{\nu }}_{\tau })<2.2\mathrm{}\times {10}^{-3\mathrm{}}$, $B(B^{-}\to {\mu }^{-}{\overline{\nu }}_{\mu })<2.1\mathrm{}\times {10}^{-5\mathrm{}}$, and $B(B^{-}\to e^{-}{\overline{\nu }}_e)<1.5\mathrm{}\times {10}^{-5\mathrm{}}$ at the 90% confidence level.