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dc.contributor.author | Papavassiliou, Joannis | |
dc.date.accessioned | 2015-04-10T08:21:42Z | |
dc.date.available | 2015-04-10T08:21:42Z | |
dc.date.issued | 2000 | |
dc.identifier.citation | Papavassiliou, Joannis 2000 Pinch technique at two loops: The case of massless Yang-Mills theories Physical Review D 62 4 045006 | |
dc.identifier.uri | http://hdl.handle.net/10550/43002 | |
dc.description.abstract | The generalization of the pinch technique beyond one loop is presented. It is shown that the crucial physical principles of gauge-invariance, unitarity, and gauge-fixing-parameter independence single out at two loops exactly the same algorithm which has been used to define the pinch technique at one loop, without any additional assumptions. The two-loop construction of the pinch technique gluon self-energy, and quark-gluon vertex are carried out in detail for the case of mass-less Yang-Mills theories, such as perturbative QCD. We present two different but complementary derivations. First we carry out the construction by directly rearranging two-loop diagrams. The analysis reveals that, quite interestingly, the well-known one-loop correspondence between the pinch technique and the background field method in the Feynman gauge persists also at two-loops. The renormalization is discussed in detail, and is shown to respect the aforementioned correspondence. Second, we present an absorptive derivation, exploiting the unitarity of the S-matrix and the underlying BRS symmetry; at this stage we deal only with tree-level and one-loop physical amplitudes. The gauge-invariant sub-amplitudes defined by means of this absorptive construction correspond precisely to the imaginary parts of the n-point functions defined in the full two-loop derivation, thus furnishing a highly non-trivial self-consistency check for the entire method. Various future applications are briefly discussed. | |
dc.language.iso | eng | |
dc.relation.ispartof | Physical Review D, 2000, vol. 62, num. 4, p. 045006 | |
dc.subject | Física | |
dc.title | Pinch technique at two loops: The case of massless Yang-Mills theories | |
dc.type | journal article | es_ES |
dc.date.updated | 2015-04-10T08:21:42Z | |
dc.identifier.doi | 10.1103/PhysRevD.62.045006 | |
dc.identifier.idgrec | 091144 | |
dc.rights.accessRights | open access | es_ES |