Related papers: Momentum Sum Rules in QCD for a Photon Target
We report on a recent calculation of the generalized parton distributions (GPDs) of the photon when the momentum transfer in the transverse direction is non-zero. We use an overlap representation of the photon GPDs in terms of the photon…
The current precision reached by lattice QCD calculations of low-energy hadronic observables, requires not only the introduction of electromagnetic corrections, but also control over all the potential systematic uncertainties introduced by…
We report on a calculation of the generalized parton distributions of the photon when there is non-zero momentum transfer both in the transverse and longitudinal directions. By taking Fourier transforms of the GPDs with respect transverse…
Sum rules for the variation of finite-density spectral density of vector channel with baryon density are derived based on dispersion relations and the operator product expansion. These sum rules may serve as constraints on the…
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…
The spectral function $\rho_{V-A}(s)$ is determined from ALEPH and OPAL data on hadronic tau decays using a neural network parametrization trained to retain the full experimental information on errors, their correlations and chiral sum…
Slight sophistications of the QCD sum-rule formalism may have great impact on the reliability of predicted hadron observables, as exemplified for the case of heavy-meson decay constants.
As first topic, the GDH sume rule is discussed in the context of a more general class of sum rules associated with the various contributions to the total photoabsorption cross section for target and beam polarization. Then I address the…
I discuss the scope and naturalness of the proton mass decomposition (or sum rule) published in PRL74, 1071 (1995) and answer a few criticisms that appeared recently in the literature, focusing particularly on its interpretation and the…
The saturation of the two Weinberg sum rules is studied at finite temperature, using recent independent QCD sum rule results for the thermal behaviour of hadronic parameters in the vector and axial-vector channels. Both sum rules are very…
Different representations of an effective, covariant theory of the hadronic interaction are examined. For this purpose we have introduced nucleon-meson vertices parametrized in terms of scalar combinations of hadronic fields, extending the…
We discuss in detail the photon structure function beyond the leading logarithm approximation. Of special concern is the factorization scheme and the hadronic input; we show how to naturally absorb large terms due to the MSbar factorization…
We examine the radiative $\Delta \to \gamma N$ transition at the real photon point $Q^2=0$ using the framework of light-cone QCD sum rules. In particular, the sum rules for the transition form factors $G_M(0)$ and $R_{EM}$ are determined up…
The Drell-Hearn-Gerasimov (DHG) sum rule relates the helicity structure of the photoabsorption cross section to the anomalous magnetic moment of the nucleon. It is based on Lorentz and gauge invariance, crossing symmetry, causality and…
Associated with the use of conventional integrated parton densities are kinematic approximations on parton momenta which result in unphysical differential distributions for final-state particles. We argue that it is important to reformulate…
The scalar and vector self-energies obtained through QCD sum rules are introduced in Quantum Hadrodynamics (QHD) equations. The results indicate that the ratios of coupling constants to respective meson mass have a very small dependence on…
We calculate the rate of the emission of the photons from the QGP. We base on the real-time kinetic approach [1] without an explicit assumption about a complete thermal equilibrium in the emitting system. ( Figures can be obtained from the…
The method of QCD light-cone sum rules is used to calculate soft nonfactorizable contributions to the decay amplitude for B -> J/psi K. The result confirms expectations that in color-suppressed decays nonfactorizable corrections can be…
We review some recent applications of QCD sum rules to $B$-decays. These include the determination of the leptonic constant $f_B$ and of the semileptonic transition amplitudes of the $B$-meson into negative and positive parity charmed…
By incorporating contributions from both the (chromo)electric scale $gT$ and (chromo)magnetic scale $g^2T$, we establish spectral sum rules of quarks for strongly coupled QCD that respect Fermi-Dirac statistics as required by quantum…