Lepton asymmetries in exclusive $b\to s{\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ decays as a test of the Standard Model

We argue that the longitudinal lepton polarization and the forward-backward asymmetries in exclusive $B\to (K,K^{\ast }){\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ decays are largely unaffected by the theoretical uncertainties in the long-distance contributions both induced by the long-range charming penguins in the ${\mathrm{\ell }}^{+}{\mathrm{\ell }}^{-}$ channel and those in the meson channels encoded in the meson transition form factors, and are mainly determined by the short-distance Wilson coefficients at the low-energy scale $\mu \simeq m_b$. Thus, the above mentioned asymmetries provide a powerful probe of the Standard Model and its extensions.