Z penguins and rare B decays

Abstract

Rare B decays of the type $b\to s{\ell }^{+}{\ell }^{-}(\nu \bar{\nu })$ are analyzed in a generic scenario where New Physics effects enter predominantly via $Z$ penguin contributions. We show that this possibility is both phenomenologically allowed and well motivated on theoretical grounds. The important role played in this context by the lepton forward-backward asymmetry in $B\to K^{\ast }{\ell }^{+}{\ell }^{-}$ is emphasized.

4 pages, 1 figure, talk presented at ICHEP2000 (Osaka, Japan, July 27-Aug 2, 2000)