dorsal/arxiv
View SchemaElectromagnetic properties of off-shell particles and gauge invariance
| Authors | S. I. Nagorny, A. E. L. Dieperink |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9803007 |
| URL | https://arxiv.org/abs/nucl-th/9803007 |
Abstract
Electromagnetic properties of off-shell particles are discussed on the basis of a purely electromagnetic reaction: virtual Compton scattering off a proton. It is shown that the definition of off-shell electromagnetic form factors is not gauge invariant and that these cannot be investigated in practice. Using only fundamental requirements of gauge invariance it is demonstrated that off-shell effects are cancelled in the longitudinal components of the total conserved current by the minimal contact current, while the off-shellness appears only in the the transverse (gauge invariant) non-pole part. This provides the possibility to introduce an on-shell extrapolated form factor F_1^+(q^2) in a gauge invariant way for the unphysical time-like region, 4m_e^2<q^2, 4M_N^2.
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"abstract": "Electromagnetic properties of off-shell particles are discussed on the basis\nof a purely electromagnetic reaction: virtual Compton scattering off a proton.\nIt is shown that the definition of off-shell electromagnetic form factors is\nnot gauge invariant and that these cannot be investigated in practice. Using\nonly fundamental requirements of gauge invariance it is demonstrated that\noff-shell effects are cancelled in the longitudinal components of the total\nconserved current by the minimal contact current, while the off-shellness\nappears only in the the transverse (gauge invariant) non-pole part. This\nprovides the possibility to introduce an on-shell extrapolated form factor\nF_1^+(q^2) in a gauge invariant way for the unphysical time-like region,\n4m_e^2\u003cq^2, 4M_N^2.",
"arxiv_id": "nucl-th/9803007",
"authors": [
"S. I. Nagorny",
"A. E. L. Dieperink"
],
"categories": [
"nucl-th"
],
"title": "Electromagnetic properties of off-shell particles and gauge invariance",
"url": "https://arxiv.org/abs/nucl-th/9803007"
},
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