相关论文: QCD Sum Rule and Perturbative QCD Approaches to Pi…
A visible improvement of the QCD sum-rule framework, achieved only recently by a slightly more sophisticated consideration of the hadron excitations and continuum, is applied to the extraction of the decay constants of heavy-light…
We compute the scattering amplitude for pion scattering in Wilson chiral perturbation theory for two degenerate quark flavors. We consider two different regimes where the quark mass m is of order (i) a\Lambda_QCD^2 and (ii)…
We present the results of calculations analyzing nucleon Compton scattering to lowest order using perturbative QCD (pQCD) methods. Two scenarios are considered: (1) the incoming photon is real; and (2) the incoming photon is virtual. The…
A short review is given of calculations of the pion electromagnetic and transition form factors within the framework of quantum chromodynamics. It is argued that both the perturbative and nonperturbative aspects of the Q^2 dependence of…
We perform a lattice QCD calculation of the hadronic light-by-light scattering amplitude in a broad kinematical range. At forward kinematics, the results are compared to a phenomenological analysis based on dispersive sum rules for…
We analyze the higher-twist effects and the SU(3)-flavour symmetry breaking in the correlation functions used to calculate form factors of pseudoscalar mesons in the QCD light-cone sum rule approach. It is shown that the Ward identities for…
We complete the calculation of the wino-nucleon scattering cross section up to the next-to-leading order in $\alpha_s$. We assume that the other sparticles are decoupled and wino interacts with the Standard Model particles via the weak…
Critical examination is made on the relation between the mass shift of vector mesons in nuclear medium and the vector-meson $-$ nucleon scattering length. We give detailed comparison between the QCD sum rule approach by two of the present…
The calculations of the double parton scattering cross sections are discussed. It is shown that the commonly used factorised formula is valid only in the limit of low cross sections. The applicability of this approximation is studied with a…
A microscopic coupled-channels model for Compton and pion scattering off the nucleon is introduced which is applicable at the lowest energies (polarizabilities) as well as at GeV energies. To introduce the model first the conventional…
We perform a study of the doubly virtual Compton scattering off a spinless target gamma* P -> gamma* P' within the Anti-de Sitter(AdS)/QCD formalism. We find that the general structure allowed by the Lorentz invariance and gauge invariance…
We argue that the perturbative QCD correlations contribute dominantly to the double parton distributions as compared to the nonperturbative ones in the limit of sufficiently large hard scales and for not parametrically small longitudinal…
A pion distribution amplitude, derived from nonlocal QCD sum rules, has been employed to calculate $F_{\gamma^*\gamma\to\pi}(Q^2)$ using light-cone sum rules, and $F_{\pi}(Q^2)$ in NLO QCD perturbation theory. Predictions are presented for…
I present generalized formulas for approximate corrections to QCD hard-scattering cross sections through second order in the perturbative expansion. The approximate results are based on recent two-loop calculations for soft and collinear…
A QCD analysis of the world data on polarized deep inelastic scattering is presented in leading and next-to-leading order. New parameterizations are derived for the quark and gluon distributions for the kinematic range $x \epsilon…
The electric ($\alpha_\pi$) and magnetic ($\beta_\pi$) Compton polarizabilities of both the charged and the neutral pion are of fundamental interest in the low-energy sector of quantum chromodynamics (QCD). Pion polarizabilities affect the…
We study analytical properties of the hard exclusive process amplitudes. We found that QCD factorization for deeply virtual Compton scattering and hard exclusive vector meson production results in the subtracted dispersion relation with the…
In the context of chiral SU(2) perturbation theory, pion-kaon scattering is analysed near the threshold to fourth chiral order. The scattering amplitude is calculated both in the relativistic framework and by using an approach similar to…
This work presents the results of our analysis of the accuracy of the pion form factor derived from the local-duality version of QCD sum rules.
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…