Related papers: Dispersive Methods and QCD Sum Rules for \gamma \g…
This thesis examines the applications and determinations of meson light-cone distribution amplitudes. The investigation of such processes, in the context of $B$ physics, provides one with a rich and extensive way of determining the Standard…
We show that at certain values of QCD condensates the nucleon QCD sum rules with "pole+continuum" model for the hadron spectrum obtain an unphysical solution. This provides constrains for the values of condensates to be consistent with…
We calculate the leading quantum corrections to the meson form factors of nonrelativistic kinks, at momentum transfer much higher than the meson mass. We consider general scalar theories which need not be integrable. Our approach is much…
We consider the pion-photon transition form factor at low to intermediate spacelike momenta within the theoretical framework of light-cone sum rules. We derive predictions which take into account all currently known contributions stemming…
The earlier suggested and developed idea of quark-hadron duality, underlying "bremsstrahlung-weighted" sum rules for total or polarized photon interaction cross sections, is applied to the description of excitation of light scalar mesons in…
The meson-photon transition form factors $\gamma\gamma^*\to P$ ($P$ stands for $\pi$, $\eta$ and $\eta'$) provide strong constraints on the distribution amplitudes of the pseudoscalar mesons. In this paper, these transition form factors are…
I illustrate the techniques and the results of the computation of order-$\as$ corrections to the production of hadrons in the collision of two virtual photons, that originate from the incoming leptons at $\epem$ colliders.
We study energy weighted sum rules of the pion and kaon propagator in nuclear matter at finite temperature. The sum rules are obtained from matching the Dyson form of the meson propagator with its spectral Lehmann representation at low and…
We derive new sum rules for the form factors of the $B_c\to J/\psi\, \ell \bar{\nu}_\ell$ semileptonic transitions, employing the vacuum-to-$B_c$ correlation function of the $J/\psi$-interpolating and $b\to c$ weak currents. In the heavy…
The hadronic contribution to the eight forward amplitudes of light-by-light scattering ($\gamma^*\gamma^*\to \gamma^*\gamma^*$) is computed in lattice QCD. Via dispersive sum rules, the amplitudes are compared to a model of the…
It is argued that it is valid to use QCD sum rules to determine the scalar and pseudoscalar two-point functions at zero momentum, which in turn determine the ratio of the strange to non-strange quark condensates $R_{su} = \frac{<\bar{s}…
We obtain the electromagnetic form factors of the nucleon, in the space-like region, using three-point function Finite Energy QCD Sum Rules. The QCD calculation is performed to leading order in perturbation theory in the chiral limit, and…
We present an overview of a novel approach to the QCD Light-Cone Sum Rule method, employing $B$-meson Light-Cone Distribution Amplitudes. This method circumvents the semi-global quark-hadron duality (QHD) approximation, which can introduce…
The method of QCD sum rules has proven to be particularly useful in heavy quark physics, where a small distance scale is provided by the inverse heavy quark mass. We present two new examples for the application of this method to B-physics:…
We perform the first next-to-leading order computation of the $\gamma^{(*)} \to V$ ($\rho, \phi, \omega$) impact factor in the QCD shockwave approach and in the most general kinematics. This paves the way to the very first quantitative…
We discuss two types of contributions to hadronic form factors in QCD: hard gluon exchange and soft wave function overlap. Within the QCD sum rule approach, the hard contribution has strong numeric suppression by factor (\alpha_s/\pi) ~ 0.1…
A sum rule for the first frequency moment of the optical absorption of a many-polaron system is derived, taking into account many-body effects in the system of constituent charge carriers of the many-polaron system. In our expression for…
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…
Cross sections for the reactions gamma^(*) gamma^(*) --> hadrons and gamma^(*) gamma^(*) --> 2 vector mesons are calculated as functions of energy (sqrt(s) > 20 GeV) and photon virtualities. Good agreement with experiment is obtained for…
We consider the calculation of the pion-photon transition form factor $F^{\gamma^*\gamma\pi^0}(Q^2)$ within light-cone sum rules focusing attention to the low-mid region of momenta. The central aim is to estimate the theoretical…