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Gluon poles from Feynman graphs, and gauge-invariant amplitudes

Journal Article · · Phys. Rev. D; (United States)
With the object of defining a physically measurable quark-gluon-plasma frequency, two SU(3) gauge-invariant amplitudes, the photon propagator, and the S matrix for quark-quark scattering are studied. It is shown through explicit calculation that, at the two-loop level (..cap alpha../sub s//sup 3/) in a general gauge, no subset of diagrams exists in these amplitudes, out of the entire set of Feynman diagrams available, with the property of yielding a gauge-invariant sum while probing the inherent non-Abelian nature of the theory. This implies that formulations of non-Abelian linear response theory based solely on gauge-dependent two-point functions or the electric field propagators are incomplete and unphysical. It also suggests that the Schwinger-Dyson equation for a properly defined, gauge-invariant, quark-gluon-plasma frequency contains an infinite number of proper skeleton graphs.
Research Organization:
Department of Physics, Oregon State University, Corvallis, Oregon 97331
OSTI ID:
6313939
Journal Information:
Phys. Rev. D; (United States), Journal Name: Phys. Rev. D; (United States) Vol. 39:8; ISSN PRVDA
Country of Publication:
United States
Language:
English