منابع مشابه
Adler Function , DIS sum rules and Crewther Relations ∗
The current status of the Adler function and two closely related Deep Inelastic Scattering (DIS) sum rules, namely, the Bjorken sum rule for polarized DIS and the Gross-Llewellyn Smith sum rule are briefly reviewed. A new result is presented: an analytical calculation of the coefficient function of the latter sum rule in a generic gauge theory in order O(α s ). It is demonstrated that the corre...
متن کاملSpin Sum Rules and Polarizabilities
The Gerasimov-Drell-Hearn sum rule and related dispersive integrals connect real and virtual Compton scattering to inclusive photoand electroproduction. Being based on universal principles as causality, unitarity, and gauge invariance, these relations provide a unique testing ground to study the internal degrees of freedom that hold a system together. The present contribution reviews the spin-d...
متن کاملDispersion Relations and Sum Rules for the π 0 → γγ ∗ and γ ∗ → γπ 0 Form Factor
Sum rules for the off-shell isovector form factor π → γγ are given in terms of the pion form factor and the γπ → ππ experimental data. Similarly, the corresponding sum rules for the off-shell isoscalar form factor are given in terms of the experimental photon-3π form factor and the γπ → 3π amplitude. For some set of parameters, e.g Γ(ρ → πγ) ≃ 90KeV , the π → γγ rate and slope parameter of the ...
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: Journal of Mathematical Physics
سال: 1972
ISSN: 0022-2488,1089-7658
DOI: 10.1063/1.1665862