Constraining Universal Extra Dimensions through B decays

Abstract

We analyze the exclusive rare $B\to K^{(\ast )}{\ell }^{+}{\ell }^{-}$, $B\to K^{(\ast )}\nu \bar{\nu }$ and $B\to K^{\ast }\gamma$ decays in the Applequist-Cheng-Dobrescu model, an extension of the Standard Model in presence of universal extra dimensions. In the case of a single universal extra dimension, we study the dependence of several observables on the compactification parameter 1/R, and discuss whether the hadronic uncertainty due to the form factors obscures or not such a dependence. We find that, using present data, it is possible in many cases to put a sensible lower bound to 1/R, the most stringent one coming from $B\to K^{\ast }\gamma$.

Comments: Invited talk at "Continuous Advances in QCD 2006", May 11-14 2006, Minneapolis (Minnesota). LaTex, 7 pages, 8 Figures