Light-front Ward-Takahashi Identity for Two-Fermion Systems
| dc.creator | Marinho, J. A. O. | |
| dc.creator | Frederico, T. | |
| dc.creator | Pace, E. | |
| dc.creator | Salme`, G. | |
| dc.creator | Sauer, P. | |
| dc.date | 2008-05-06 | |
| dc.date.accessioned | 2026-07-07T11:33:45Z | |
| dc.date.available | 2026-07-07T11:33:45Z | |
| dc.description | 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 quasi-potential 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 quasi-potential expansion, and the divergence of the proposed current satisfies a Ward-Takahashi identity at any given order of the expansion. In the quasi-potential 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 quasi-potential 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. | |
| dc.description | 48 pages, 3 figures | |
| dc.identifier | https://arxiv.org/abs/0805.0707 | |
| dc.identifier | http://arxiv.org/abs/0805.0707 | |
| dc.identifier | Phys.Rev.D77:116010,2008 | |
| dc.identifier | doi:10.1103/PhysRevD.77.116010 | |
| dc.identifier.uri | http://salesiana.dossiersoluciones.com/handle/123456789/198006 | |
| dc.subject | High Energy Physics - Phenomenology | |
| dc.subject | Nuclear Theory | |
| dc.title | Light-front Ward-Takahashi Identity for Two-Fermion Systems | |
| dc.type | text |