$B \to K^* \ell^+ \ell^-$ as a probe of Universal Extra Dimensions

We study some rare B decays induced by $b \to s$ transition within the Standard Model and in the Appelquist-Cheng-Dobrescu model, which is a New Physics scenario with a single universal extra dimension. In particular, we discuss the dependence on the radius $R$ of the compactified extra-dimension of the branching ratio, the forward-backward asymmetry and the $K^*$ helicity distributions for the decay modes $B \to K^* \ell^+ \ell^-$, with $\ell^-=e^-,\mu^-$, and the tau polarization asymmetries for the mode $B \to K^* \tau^+ \tau^-$.