Light-front Ward-Takahashi identity for two-fermion systems

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dc.identifier.uri Marinho, J.A.O. Frederico, T. Pace, E. Salmè, G. Sauer, P.U. 2020-01-10T08:21:17Z 2020-01-10T08:21:17Z 2008
dc.identifier.citation Marinho, J.A.O.; Frederico, T.; Pace, E.; Salmè, G.; Sauer, P.U.: Light-front Ward-Takahashi identity for two-fermion systems. In: Physical Review D 77 (2008), Nr. 11, 116010. DOI:
dc.description.abstract We propose a three-dimensional electromagnetic current operator within light-front dynamics that satisfies a light-front Ward-Takahashi identity for two-fermion systems. The light-front current operator is obtained by a quasipotential reduction of the four-dimensional current operator and acts on the light-front valence component of bound or scattering states. A relation between the light-front valence wave function and the four-dimensional Bethe-Salpeter amplitude both for bound or scattering states is also derived, such that the matrix elements of the four-dimensional current operator can be fully recovered from the corresponding light-front ones. The light-front current operator can be perturbatively calculated through a quasipotential expansion, and the divergence of the proposed current satisfies a Ward-Takahashi identity at any given order of the expansion. In the quasipotential expansion the instantaneous terms of the fermion propagator are accounted for by the effective interaction and two-body currents. We exemplify our theoretical construction in the Yukawa model in the ladder approximation, investigating in detail the current operator at the lowest nontrivial order of the quasipotential expansion of the Bethe-Salpeter equation. The explicit realization of the light-front form of the Ward-Takahashi identity is verified. We also show the relevance of instantaneous terms and of the pair contribution to the two-body current and the Ward-Takahashi identity. eng
dc.language.iso eng
dc.publisher College Park, MD : American Physical Society
dc.relation.ispartofseries Physical Review D 77 (2008), Nr. 11
dc.rights Es gilt deutsches Urheberrecht. Das Dokument darf zum eigenen Gebrauch kostenfrei genutzt, aber nicht im Internet bereitgestellt oder an Außenstehende weitergegeben werden.
dc.subject interacting-fermion systems eng
dc.subject Ward-Takahashi identity eng
dc.subject Bethe-Salpeter (BS) equation eng
dc.subject.ddc 530 | Physik ger
dc.title Light-front Ward-Takahashi identity for two-fermion systems
dc.type article
dc.type Text
dc.relation.essn 1089-4918
dc.relation.essn 1550-2368
dc.relation.essn 2470-0029
dc.relation.issn 0556-2821
dc.relation.issn 1550-7998
dc.bibliographicCitation.issue 11
dc.bibliographicCitation.volume 77
dc.bibliographicCitation.firstPage 116010
dc.description.version publishedVersion
tib.accessRights frei zug�nglich

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