LEPTON ASYMMETRIES IN EXCLUSIVE B-]SL(-) DECAYS AS A TEST OF THE STANDARD MODEL()L()

We argue that the longitudinal lepton polarization and the forward-bac kward asymmetries in exclusive B --> (K, K) l(+)l(-) decays are large ly unaffected by the theoretical uncertainties in the long-distance co ntributions both induced by the long-range charming penguins in the l( +)l(-) channel and those in the meson channels encoded in the meson tr ansition form factors, and are mainly determined by the short-distance Wilson coefficients at the low-energy scale mu similar or equal to m( b). Thus, the abovementioned asymmetries provide a powerful probe of t he Standard Model and its extensions. (C) 1998 Published by Elsevier S cience B.V. All rights reserved.