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We adopt a non-perturbative relativistic constituent-quark model for the pi-meson electromagnetic form factor, which have successfully predicted experimental results, and supplement it with the effective momentum-dependent quark mass to…
Photoproduction of a pair of particles with large invariant mass is a natural extension of collinear QCD factorization theorems which have been much studied for deeply virtual Compton scattering and deeply virtual meson production. We…
The perturbative quantum chromodynamics (QCD) is quite successful in the description of main features of multiparticle production processes. Ten most appealing characteristics are described in this brief review talk and compared with QCD…
In a study of the elastic pion form factor for large momentum transfers based on a modified perturbative QCD (PQCD) approach we have included helicity components that are customarily neglected. Along with the inclusion of transverse…
Corrections due to gluon condensate to electromagnetic form factors of the transition $\pi+\gamma^* \to A_1$ are calculated by standard QCD sum rules technique. The obtained results are compared to the corresponding light-cone QCD sum…
A model which combines the perturbative behavior of QCD with low energy phenomenology in a unified framework is developed. This is achieved by applying a similarity transformation to the QCD Hamiltonian which removes interactions between…
The improved calculation method of quark distributions in hadrons in the framework of QCD sum rules is presented. The imaginary part of the virtual photon scattering amplitude on some hadronic current is considered in the case, when initial…
Compton scattering of polarized radiation in a strong magnetic field is considered. The recipe for calculation of the scattering matrix elements, the differential and total cross sections based on quantum electrodynamic (QED) second order…
We discuss the status of the pion distribution amplitude (DA) in connection with QCD sum rules and experimental data on the $\gamma^*\gamma^\to \pi^0$ transition form factor. Contents: (a) Pion DA in generalized QCD Sum Rules (SRs); (b)…
We have studied the applications of the anomaly sum rule to the transition form factors of light pseudoscalar mesons: $\pi^0$, $\eta$ and $\eta'$. This nonperturbative QCD approach can be used even if the QCD factorization is broken. The…
We study two versions of lightcone sum rules to calculate the $\gamma^*\gamma\rightarrow\pi^0$ transition form factor (TFF) within QCD. While the standard version is based on fixed-order perturbation theory by means of a power-series…
The properties of net quark number fluctuations in the vicinity of the QCD chiral phase transition are discussed in terms of an effective chiral model in the mean-field approximation. We focus on the ratio of the fourth- to second- order…
A new analysis of baryon sum rules is done with modern values of parameters and known perturbative corrections. The restriction for gluon and quark condensates and the new value of nucleon coupling constant are found.
Several topics in hadron physics at different scales of resolution are discussed. First, deep-inelastic scattering from nucleons and nuclei is viewed in a light-cone coordinate space picture. Then the smooth transition from parton to hadron…
We compare two widely used approaches to the description of hadron properties: QCD sum rules and constituent quark models. Making use of the dispersion formulation of the quark model, we show that both approaches lead to similar spectral…
We apply the perturbative QCD factorization theorem developed recently for nonleptonic heavy meson decays to the radiative decay $B\to K^*\gamma$. In this formalism the evolution of the Wilson coefficients from the $W$ boson mass down to…
QED perturbation theory in a background field has been conjectured to break down for sufficiently high field intensity. The high-intensity behavior of a field theory is however intertwined with its high-energy (UV) behavior. Here we show…
A unique feature of generalised parton distributions is their relation to the QCD energy-momentum tensor. In particular, they provide access to the mechanical properties of the proton i.e. the distributions of pressure and shear stress…
We calculate the next-to-leading order (NLO) quantum chromodynamics (QCD) corrections to $\gamma+\gamma\to \eta_c+c+\bar{c}$, $\gamma+\gamma\to \eta_b+b+\bar{b}$ and $\gamma+\gamma\to B_c+b+\bar{c}$ processes in the framework of…
We predict contributions of higher $K$-resonances to the radiative rare decays $b\to s\gamma$, in the framework of the QCD sum rules on the light cone, which combines the traditional QCD sum rule method with the description of final state…