Exotic Charmonium and Bottomonium-like Resonances

Many new states in the charmonium and bottomonium mass region were recently discovered by the BaBar, Belle and CDF Collaborations. We use the QCD Sum Rule approach to study the possible structure of some of these states. In particular we identify the recently observed bottomonium-like resonance $Z_b^+(10610)$ with the first excitation of the tetraquark $X_b(1^{++})$, the analogue of the X(3872) state in the charm sector.

$D^{*}D rho $ vertex from QCD sum rules

We calculate the form factors and the coupling constant in the $D^{*}D rho $ vertex in the framework of QCD sum rules. We evaluate the three point correlation functions of the vertex considering both $ D $ and $ rho $ mesons off--shell. The form factors obtained are very different but give the same coupling constant: $g_{D^{*}D rho} = 4.1 pm 0.1$ GeV$^{-1}$.