Related papers: Soft Matrix Elements in Non-local Chiral Quark Mod…
The transversity form factors of the pion, involving matrix elements of bilocal tensor currents, are evaluated in chiral quark models, both in the local Nambu--Jona-Lasinio with the Pauli-Villars regularization, as well as in nonlocal…
We investigate the form factors for pseudoscalar-meson-photon transitions by means of dispersive QCD sum rules and demonstrate that most of the measurements done so far (in particular, those by BaBar for $\eta,$ $\eta',$ and $\eta_c$ and…
Pion transition form factor for the process $\gamma*\gamma*\to \pi^0$ at space-like values of photon momenta is calculated within the effective quark-meson model with the interaction induced by instanton exchange. The leading and…
The form factors of the light pseudoscalar mesons are investigated in a dispersive formalism based on hadronic unitarity, analyticity and the OPE expansion of the QCD Green functions. We propose generalizations of the original mathematical…
We present a brief review of results of chiral quark models for soft matrix elements in the pion state, appearing in high-energy processes as well as accessible in present and future lattice studies. A particular attention is paid to the…
We study the non-forward matrix elements of twist-2 QCD light-ray operators and their representations in terms of skewed and double distributions, considering the pion as well as the nucleon. We point out the importance of explicitly…
We study the operator product expansion (OPE) and quark-hadron duality for 2- and 3-point correlators of the axial (A) and pseudoscalar (P) currents of the light quarks. In the chiral limit these correlators are often dominated by…
The behavior of the transition pion form factor for processes \gamma^*\gamma -> \pi^0 and \gamma^* \gamma^* -> \pi^0 at large values of space-like photon momenta is estimated within the nonlocal covariant quark-pion model. It is shown that,…
The relativistic amplitudes of pion photoproduction are evaluated by dispersion relations at t=const. The imaginary parts of the amplitudes are taken from the MAID model covering the absorption spectrum up to center-of-mass energies W = 2.2…
The Nambu--Jona-Lasinio model is utilized to investigate the pion and kaon photon leading-twist transition distribution amplitudes using proper time regularization. Separately, the properties of the vector and axial vector pion photon…
A global fit to the data from different collaborations (CELLO, CLEO, BaBar) on the pion-photon transition form factor is carried out using light-cone sum rules. The analysis includes the next-to-leading QCD radiative corrections and the…
Results for the proton and neutron electric and magnetic form factors as well asthe nucleon axial and induced pseudoscalar form factors are presented for the chiral constituent quark model based on Goldstone-boson-exchange dynamics. The…
The description of the VV'P form factors (V,V' stands for vector particles and P for a pseudoscalar meson) for different particles virtualities remains a challenge for the theory of strong interactions. While their chiral limit is well…
Chiral quark models offer a practical and simple tool to describe covariantly both low and high energy phenomenology in combination with QCD evolution. This can be done in full harmony with chiral symmetry and electromagnetic gauge…
We study the form factors for semileptonic decays of $D$-mesons. That is, we consider the matrix element of the weak left-handed quark current for the transitions $D \rightarrow P$ and $D \rightarrow V$, where $P$ and $V$ are light…
In this talk it is reported on an analysis of the form factors for the transitions from a photon to one of the pseudoscalar mesons pi0, eta, eta', etac within the modified perturbative approach in which quark transverse degrees of freedom…
A covariant quark model, based both on the spectator formalism and on vector meson dominance, and previously calibrated by the physical data, is here extended to the unphysical region of the lattice data by means of one single extra…
We present a novel framework for analyzing four-body semileptonic weak decays, performing the first high-twist analysis of the $D_s \to \left[ \pi\pi \right]_{\rm S}$ form factors using light-cone distribution amplitudes for the isoscalar…
We present a quantum theory for the dynamic structure factors in non-equilibrium, correlated, two-component systems such as plasmas or warm dense matter. Using this general framework, we derive expressions for effective local field…
Pion electro- and photoproduction off the nucleon close to threshold is studied in covariant baryon chiral perturbation theory at O($p^3$) in the extended-on-mass-shell scheme, with the explicit inclusion of the $\Delta(1232)$ resonance.…