dorsal/arxiv
View SchemaCompton scattering from a pion and off-shell effects
| Authors | S. Scherer |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9506028 |
| URL | https://arxiv.org/abs/nucl-th/9506028 |
Abstract
We discuss the most general form of the electromagnetic vertex of an off-shell pion. The framework of chiral perturbation theory is used to illustrate the representation dependence of the electromagnetic three-point Green's function. For that purpose we discuss the concept of field transformations which, in comparison with the standard Gasser and Leutwyler Lagrangian, generate equivalent Lagrangians containing additional terms at order p^4 proportional to the lowest-order equation of motion. We consider Compton scattering from a pion to show that calculations involving different off-shell effects in the s- and u-channel pole diagrams may nevertheless lead to the same on-shell Compton scattering amplitude. This is a result of the equivalence theorem which states that two equivalent Lagrangians predict the same S-matrix elements even though they may generate a different off-shell behaviour of Green's functions. We conclude that off-shell effects are not only model dependent but also representation dependent.
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"date_created": "2026-03-02T18:00:15.534000Z",
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"abstract": "We discuss the most general form of the electromagnetic vertex of an\noff-shell pion. The framework of chiral perturbation theory is used to\nillustrate the representation dependence of the electromagnetic three-point\nGreen\u0027s function. For that purpose we discuss the concept of field\ntransformations which, in comparison with the standard Gasser and Leutwyler\nLagrangian, generate equivalent Lagrangians containing additional terms at\norder p^4 proportional to the lowest-order equation of motion. We consider\nCompton scattering from a pion to show that calculations involving different\noff-shell effects in the s- and u-channel pole diagrams may nevertheless lead\nto the same on-shell Compton scattering amplitude. This is a result of the\nequivalence theorem which states that two equivalent Lagrangians predict the\nsame S-matrix elements even though they may generate a different off-shell\nbehaviour of Green\u0027s functions. We conclude that off-shell effects are not only\nmodel dependent but also representation dependent.",
"arxiv_id": "nucl-th/9506028",
"authors": [
"S. Scherer"
],
"categories": [
"nucl-th",
"hep-ph"
],
"title": "Compton scattering from a pion and off-shell effects",
"url": "https://arxiv.org/abs/nucl-th/9506028"
},
"schema_id": "dorsal/arxiv",
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"execution_id": "97ebc091-0acd-45f1-b5a8-655a0090019a",
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