We report the results of a new search for flavor-changing neutral-current decays of the b quark and present a 90%-confidence-level upper limit for the branching fraction for B→$l^{+}$$l^{\mathrm{-}}$X of 1.2×${10}^{\mathrm{-}3}$.

• Received 1 April 1987

DOI:https://doi.org/10.1103/PhysRevD.35.3533