Constraining Universal Extra Dimensions through B decays

We analyze the exclusive rare $B \to K^{(*)} \ell^+ \ell^-$, $B \to K^{(*)} \nu \bar \nu$ and $B \to K^* \gamma$ 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 $B \to K^* \gamma$.Comment: Invited talk at "Continuous Advances in QCD 2006", May 11-14 2006, Minneapolis (Minnesota). LaTex, 7 pages, 8 Figure

Anomalous AV^*V vertex function in the soft-wall holographic model of QCD

I consider the three-point function of two vector and one axial-vector currents. In the kinematic configuration in which one of the two vector currents corresponds to an on-shell soft photon, such a vertex is described in QCD by two functions, $w_L$ and $w_T$. After reviewing the properties of these functions in QCD, I describe the result obtained using the soft-wall holographic model of QCD with the addition of the Chern-Simons term and I compare it with the QCD outcome. I also discuss a relation, proposed by Son and Yamamoto, that connects $w_L$ and $w_T$ to the two-point functions $\Pi_{VV}$ and $\Pi_{AA}$.Comment: LaTeX, 8 pages. Talk given at the conference "Xth Quark Confinement and the Hadron Spectrum", Munich, 8-12 October 201

Weak Decays of Heavy Quarks

We review some aspects of weak decays of hadrons containing one heavy quark. The main emphasis is on $B$ physics, in particular in the framework of the Heavy Quark Effective Theory.Comment: LaTex, 48 pages, 4 figures; uses psfig, sprocl.sty. To be published in the Boris Ioffe Festschrift "At the Frontier of Particle Physics/ Handbook of QCD", edited by M. Shifman, (World Scientific

On the coupling gf0K+K−g_{f_0K^+K^-} and the structure of f0(980)f_0(980)

We use light-cone QCD sum rules to evaluate the strong coupling $g_{f_0 K^+ K^-}$ which enters in several analyses concerning the scalar $f_0(980)$ meson. The result: $6.2\le g_{f_0 K^+ K^-}\le 7.8$ GeV is larger than in previous determinations.Comment: Talk given at the International Europhysics Conference on High Energy Physics - EPS 2003, July 17-23, Aachen, Germany. LaTex, 3 pages, 1 eps figur