Related papers: Aspects of QCD Current Algebra on a Null Plane
The inverse eigenvalues of the Dirac operator in the Schwinger model satisfy the same Leutwyler-Smilga sum rules as in the case of QCD with one flavor. In this paper we give a microscopic derivation of these sum rules in the sector of…
We review the recent progress in the applications of QCD sum rules to hadron properties with the emphasis on the following selected problems: (i) development of new algorithms for the extraction of ground-state parameters from two-point…
We derive two sum rules by studying the low energy Compton scattering on a target of arbitrary (nonzero) spin j. In the first sum rule, we consider the possibility that the intermediate state in the scattering can have spin |j \pm 1| and…
The QCD sum rules in the large-$N_c$ limit for the light non-strange vector, axial and scalar mesons are considered assuming a string-like linear spectrum for the radially excited states. We propose a improved method for combined analysis…
An introduction to the method of QCD sum rules is given for those who want to learn how to use this method. Furthermore, we discuss various applications of sum rules, from the determination of quark masses to the calculation of hadronic…
The history of Current Algebra is reviewed up to the appearance of the Adler-Weisberger sum rule. Particular emphasis is given to the role current algebra played for the historical struggle in strong interaction physics of elementary…
We show that symmetries and gauge symmetries of a large class of 2-dimensional sigma models are described by a new type of a current algebra. The currents are labeled by pairs of a vector field and a 1-form on the target space of the sigma…
A general class of inverse-moment sum rules was previously derived by the authors in a chiral perturbation theory (ChPT) study at two-loop order of the isospin and hypercharge vector-current propagators. Here, we address the evaluation of…
The forms of the neutral, non-strange pseudoscalar propagator matrix and mixed axial current correlator, $\lngle0|T(A_\mu^3 A_\nu^8)|0\rangle$, are discussed at next-to-leading (one-loop) order in chiral perturbation theory, and the results…
We derive a set of sum rules for the light-by-light scattering and fusion: $\gamma\gamma \to all$, and verify them in lowest order QED calculations. A prominent implication of these sum rules is the superconvergence of the…
A current-current correlator with the quantum numbers of the omega meson is studied in a nuclear medium. Using weighted finite energy sum rules and dispersion relations for the current-nucleon forward scattering amplitude it is shown that…
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…
Based on an effective Lagrangian which combines chiral SU(3) dynamics with vector meson dominance, we have developed a model for the s-wave vector meson-nucleon scattering amplitudes. We use this as an input for the low energy part of the…
In order to clarify the connection between {\it current} and {\it constituent} quarks (of u,d,s flavors), several authors have used the lightlike chiral $SU(3)\otimes SU(3)$ algebra as a central concept. This literature is reviewed here…
We derive QCD sum rules from the nucleon two-point function in nuclear medium, calculating its specral function in chiral perturbation theory to one loop. Our calculation shows the inadequacy of the commonly used ansatz to represent the…
We compute the algebra of left and right currents for a principal chiral model with arbitrary Wess-Zumino term on supergroups with zero Killing form. We define primary fields for the current algebra that match the affine primaries at the…
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 deduce momentum sum rules for the parton structure functions of a photon target. Non-perturbative QCD contribution to the momentum sum rules follows from conservation of the energy--momentum tensor and it is calculated through the…
Dispersive sum rules constitute long-standing tools for extracting hadron features from QCD. We estimate the systematic uncertainties induced by assuming quark-hadron duality and improve the accuracy of the resulting predictions by…
The fixed-mass sum rules for the deuteron target have been derived by using the connected matrix element of the current anti-commutation relation on the null-plane. From these sum rules we obtain the relation between the pseudo-scalar meson…