Sum rules in perturbation theory
نویسندگان
چکیده
منابع مشابه
QCD sum rules vs . chiral perturbation theory
QCD sum rules are useful tools for studying the spectral properties of hadrons; however, assumptions underlying standard sum-rule analyses can lead to inconsistencies with known results of chiral perturbation theory. This possibility is demonstrated with QCD sum-rule extractions of the nucleon mass and σ term. In both cases, inconsistent chiral behavior leads to an uncertainty in the sum-rule p...
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We derive light-cone sum rules (LCSRs) for exclusive B-meson decays into light energetic hadrons from correlation functions within soft-collinear effective theory (SCET). In these sum rules the short-distance scale refers to “hard-collinear” interactions with virtualities of order ΛQCDmb. Hard scales (related to virtualities of order mb) are integrated out and enter via external coefficient fun...
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We derive non-perturbative sum rules in SU(N) lattice gauge theory at finite temperature. They relate the susceptibilities of the trace anomaly and energy-momentum tensor to temperature derivatives of the thermodynamic potentials. Two of them have been derived previously in the continuum and one is new. In all cases, at finite latttice spacing there are important corrections to the continuum su...
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Assuming the S-matrix on noncommutative (NC) spacetime can still be developped perturbatively in terms of the time-ordered exponential of the interaction Lagrangian, we investigate the perturbation theory of NC field theory. We first work out with care some typical Green functions starting from the usual concepts of time-ordering and commutation relations for free fields. The results are found ...
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A Dirac picture perturbation theory is developed for the time evolution operator in classical dynamics in the spirit of the Schwinger-Feynman-Dyson perturbation expansion and detailed rules are derived for computations. Complexification formalisms are given for the time evolution operator suitable for phase space analyses, and then extended to a two-dimensional setting for a study of the geomet...
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ژورنال
عنوان ژورنال: Zeitschrift f�r Physik
سال: 1967
ISSN: 1434-6001,1434-601X
DOI: 10.1007/bf01331235