2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/140179We 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 $\ell^-=e^-,μ^-$, and the tau polarization asymmetries for the mode $B \to K^* τ^+ τ^-$.Talk given at IFAE 2007, Naples, April 11-13. LaTex, 6 pages, 2 eps figuresHigh Energy Physics - Phenomenologytext