Fernando Silveira Navarra

New Charmonium States in QCD Sum Rules: a Concise Review

In the past years there has been a revival of hadron spectroscopy. Many interesting new hadron states were discovered experimentally, some of which do not fit easily into the quark model. This situation motivated a vigorous theoretical activity. This is a rapidly evolving field with enormous amount of new experimental information. In the present report we include and discuss data which were released very recently. The present review is the first one written from the perspective of QCD sum rules (QCDSR), where we present the main steps of concrete calculations and compare the results with other approaches and with experimental data.

D* D pi and B* B pi form-factors from QCD sum rules

Abstract The H ∗ Hπ form factor for H = B and D mesons is evaluated in a QCD sum rule calculation. We study the Borel sum rule for the three point function of two pseudoscalar and one vector meson currents up to order four in the operator product expansion. The double Borel transform is performed with respect to the heavy meson momenta. We discuss the momentum dependence of the form factors and two different approaches to extract the H ∗ Hπ coupling constant.

QCD sum rule approach for the light scalar mesons as four-quark states

Abstract We study the two point-function for the scalar mesons σ, κ, f 0 ( 980 ) and a 0 ( 980 ) as diquak–antidiquark states. We also study the decays of these mesons into ππ, Kπ and K K ¯ . We find that the couplings are consistent with existing experimental data, supporting the four-quark structure for the light scalar mesons.

The J/ψDD vertex in QCD sum rules

Abstract The J / ψDD form factor is evaluated in a QCD sum rule calculation for both D and J / ψ 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 / ψ meson is off-shell, but they lead to the same coupling constant in the J / ψDD vertex.

D and ρ mesons: who resolves whom?

Abstract The DDρ form factor is evaluated in a QCD sum rule calculation for both D and ρ off-shell mesons. We study the double Borel sum rule for the three point function of two pseudoscalar and one vector meson currents. We find that the momentum dependence of the form factors is very different if the D or the ρ meson is off-shell, but they lead to the same coupling constant in the DDρ vertex. We discuss two different approaches to extract the DDρ coupling constant.

Weak decays of heavy hadrons into dynamically generated resonances

In this paper, we present a review of recent works on weak decay of heavy mesons and baryons with two mesons, or a meson and a baryon, interacting strongly in the final state. The aim is to learn about the interaction of hadrons and how some particular resonances are produced in the reactions. It is shown that these reactions have peculiar features and act as filters for some quantum numbers which allow to identify easily some resonances and learn about their nature. The combination of basic elements of the weak interaction with the framework of the chiral unitary approach allow for an interpretation of results of many reactions and add a novel information to different aspects of the hadron interaction and the properties of dynamically generated resonances.

QCD sum rules study of the meson Z+(4430)

Abstract We use QCD sum rules to study the recently observed meson Z + ( 4430 ) , considered as a D ∗ D 1 molecule with J P = 0 − . We consider the contributions of condensates up to dimension eight and work at leading order in α s . We get m Z = ( 4.40 ± 0.10 ) GeV in a very good agreement with the experimental value. We also make predictions for the analogous mesons Z s and Z b b considered as D s ∗ D 1 and B ∗ B 1 molecules, respectively. For Z s we predict m Z s = ( 4.70 ± 0.06 ) GeV , which is above the D s ∗ D 1 threshold, indicating that it is probably a very broad state and, therefore, difficult to observe experimentally. For Z b b we predict m Z b b = ( 10.74 ± 0.12 ) GeV , in agreement with quark model predictions.

Form-factors and decay rates for heavy Lambda semileptonic decays from QCD sum rules

QCD sum rules for the determination of form factors of

Charged Exotic Charmonium States

{\ensuremath{\Lambda}}_{b}

Intrinsic charm component of the nucleon.

and