منابع مشابه
Parton Model Sum Rules
This review article discusses the experimental and theoretical status of various Parton Model sum rules. The basis of the sum rules in perturbative QCD is discussed. Their use in extracting the value of the strong coupling constant is evaluated and the failure of the naive version of some of these rules is assessed. This work was supported by the Director, Office of Energy Research, Office of H...
متن کاملSum Rules for Higher-twist Parton Distributions
In deep-inelastic scattering experiments, there is a general connection between subtractions in dispersion relations, violations of sum-rules and δ-functions in parton distribution functions. It is explained why one might expect a small violation in sum rules for the twist-3 distribution functions gT (x) and hL(x) when the sumrules are applied to x 6= 0 data only. The non-perturbative predictio...
متن کاملParton-Hadron duality in QCD sum rules: quantum mechanical examples
Motivated by recent work on three-point QCD sum rules in heavy quark physics, we use the simple quantum mechanical models to study the basic issue of duality in three-point sum rules. We show that while in all of these models the duality in two-point sum rules works fine, the duality in three-point sum rules may be 100%violated, leading to completely unreliable predictions for the matrix elemen...
متن کاملQCD Sum Rules and Models for Generalized Parton Distributions
I use QCD sum rule ideas to construct models for generalized parton distributions. To this end, the perturbative parts of QCD sum rules for the pion and nucleon electromagnetic form factors are interpreted in terms of GPDs and two models are discussed. One of them takes the double Borel transform at adjusted value of the Borel parameter as a model for nonforward parton densities, and another is...
متن کاملNonequilibrium Sum Rules for the Holstein Model
We derive frequency moment sum rules for the retarded electronic Green's function and self-energy of the Holstein model for both equilibrium and nonequilibrium cases. We also derive sum rules for the phonon propagator in equilibrium and nonequilibrium. These sum rules allow one to benchmark nonequilibrium calculations and help with interpreting the behavior of electrons driven out of equilibriu...
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ژورنال
عنوان ژورنال: Annual Review of Nuclear and Particle Science
سال: 1996
ISSN: 0163-8998,1545-4134
DOI: 10.1146/annurev.nucl.46.1.609