منابع مشابه
Classical Photoabsorption Sum Rules
We u s e a q u a n tum loop expansion to derive sum rule constraints on polarized photoabsorption cross sections in the Standard Model, generalizing earlier results obtained by Altarelli, Cabibbo, and Maiani. We s h o w that the logarithmic integral of the spin-dependent photoabsorption cross section R 1 th dd Born () v anishes for any 2 ! 2 process a! bc in the classical, tree-graph approximat...
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Following the idea of the quark-hadron duality we present, within the constituent quark model approach, the relations between different bremsstrahlung-weihgted in-tegrals of the nucleon resonance photoexcitation cross sections and correlation functions of the quark dipole moments in the nucleon ground state. These functions are of interest for checking detailed quark-configuration structure of ...
متن کاملSemi Classical Sum Rules and Generalized Coherent States
Various semi-classical sum rules are obtained for matrix elements of smooth observables using semi-classical estimates of time evolved coherent states together with stationary phase theorems.
متن کاملParton 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 کاملResistance-Distance Sum Rules*
The chemical potential for a novel intrinsic graph metric, the resistance distance, is briefly recalled, and then a number of »sum rules« for this metric are established. »Global« and »local« types of sum rules are identified. The sums in the »global« sum rules are graph invariants, and the sum rules provide inter-relations amongst different invariants, some involving the resistance distance wh...
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ژورنال
عنوان ژورنال: Physics Letters B
سال: 1995
ISSN: 0370-2693
DOI: 10.1016/0370-2693(95)00372-r