dorsal/arxiv
View SchemaChiral symmetry and parametrization of scalar resonances
| Authors | L. O. Arantes, M. R. Robilotta |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/0502001 |
| URL | https://arxiv.org/abs/nucl-th/0502001 |
Abstract
The linear $\s$-model is used to study the effects of chiral symmetry in unitarized amplitudes incorporating scalar resonances. When just a single resonance is present, we show that the iteration of a chiral tree amplitude by means of regularized two-pion loops preserves the smallness of $\p\p$ interaction at low energies and estimate the importance of pion off-shell contributions. The inclusion of a second resonance is performed by means of a chiral extension of the linear $\s$-model lagrangian. The new $\p\p$ ampitude at tree level complies with low-energy theorems, depends on a mixing angle and has a zero for a given energy between the resonance masses. The unitarization of this amplitude by means of two-pion loops preserves both its chiral low energy behavior and the position of this zero confirming, in a lagrangian framework, conclusions drawn previously by T\"ornqvist. Finally, we approximate and generalize our results and give a friendly expression that can be used in the parametrization of $N$ coupled scalar resonances.
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"abstract": "The linear $\\s$-model is used to study the effects of chiral symmetry in\nunitarized amplitudes incorporating scalar resonances. When just a single\nresonance is present, we show that the iteration of a chiral tree amplitude by\nmeans of regularized two-pion loops preserves the smallness of $\\p\\p$\ninteraction at low energies and estimate the importance of pion off-shell\ncontributions. The inclusion of a second resonance is performed by means of a\nchiral extension of the linear $\\s$-model lagrangian. The new $\\p\\p$ ampitude\nat tree level complies with low-energy theorems, depends on a mixing angle and\nhas a zero for a given energy between the resonance masses. The unitarization\nof this amplitude by means of two-pion loops preserves both its chiral low\nenergy behavior and the position of this zero confirming, in a lagrangian\nframework, conclusions drawn previously by T\\\"ornqvist. Finally, we approximate\nand generalize our results and give a friendly expression that can be used in\nthe parametrization of $N$ coupled scalar resonances.",
"arxiv_id": "nucl-th/0502001",
"authors": [
"L. O. Arantes",
"M. R. Robilotta"
],
"categories": [
"nucl-th"
],
"title": "Chiral symmetry and parametrization of scalar resonances",
"url": "https://arxiv.org/abs/nucl-th/0502001"
},
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