Investigating the tetraquark structure of the new mesons

Using the QCD sum rule approach we investigate the possible four-quark structure of the recently observed mesons $D_{sJ}^{+}(2317)$, firstly observed by BaBaR, X(3872), firstly observed by BELLE and $D_0^{*0}(2308)$ observed by BELLE. We use diquark-antidiquark currents and work in full QCD, without relying on $1/m_c$ expansion. Our results indicate that a four-quark structure is acceptable for these mesons.Comment: 4 pages 1 eps figure, proceedings of the XVIII Workshop on Hadronic Interactions (RETINHA-18) Sao Paulo-S

J/psi D*D* vertex from QCD sum rules

We calculated the strong form factor and coupling constant for the $J/\psi D^* D^*$ vertex in a QCD sum rule calculation. We performed a double Borel sum rule for the three point correlation function of vertex considering both $J/\psi$ and $D^*$ mesons off--shell. The form factors obtained are very different, but they give the same coupling constant.Comment: 7 pages and 4 figures, replaced version accepted for publication in Phys. Lett.

Looking for meson molecules in B decays

We discuss the possibility of observing a loosely bound molecular state in a B three-body hadronic decay. In particular we use the QCD sum rule approach to study a $\eta^\prime-\pi$ molecular current. We consider an isovector-scalar $I^G J^{PC}= 1^-~0^{++}$ molecular current and we use the two-point and three-point functions to study the mass and decay width of such state. We consider the contributions of condensates up to dimension six and we work at leading order in $\alpha_s$. We obtain a mass around 1.1 GeV, consistent with a loosely bound state, and a $\eta^\prime-\pi\rightarrow K^+ K^-$ decay width around 10 MeV.Comment: 7 pages, 8 figure

The J/ψDDJ/\psi D D Vertex in QCD Sum Rules

The $J/\psi D D$ form factor is evaluated in a QCD sum rule calculation for both $D$ and $J/\psi$ off-shell mesons. We study the double Borel sum rule for the three point function of two pseudoscalar and one vector meson current. We find that the momentum dependence of the form factors is different if the $D$ or the $J/\psi$ meson is off-shell, but they lead to the same coupling constant in the $J/\psi D D$ vertex.Comment: 11 pages, Latex, 4 eps figure