dorsal/arxiv
View SchemaChiral unitary meson-baryon dynamics in the presence of resonances: Elastic pion-nucleon scattering
| Authors | Ulf-G. Meißner, J. A. Oller |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9912026 |
| URL | https://arxiv.org/abs/nucl-th/9912026 |
| DOI | 10.1016/S0375-9474(00)00150-0 |
| Journal | Nucl.Phys. A673 (2000) 311-334 |
Abstract
We develop a novel approach to chiral meson-baryon dynamics incorporating unitarity constraints and explicit resonance fields. It is based on the most general structure of any pion-nucleon partial wave amplitude neglecting the unphysical cuts as derived from the N/D method. This amplitude is then matched to the one-loop heavy baryon chiral perturbation theory result at third order and to tree level exchanges of baryon- and meson states in the s,t and u channels. This generates the left-hand cuts. The unitarization procedure does not involve form factors or regulator functions. The resonance parameters are determined from fits to the S- and P-wave pion-nucleon partial wave amplitudes for energies up to 1.3 GeV. In particular, the $\Delta (1232)$ is accurately reproduced whereas scalar and vector meson couplings are less precisely pinned down. We also obtain a satisfactory description of the $\pi$N threshold parameters. Further extensions of this method to coupled channels and the three-flavor case are briefly discussed.
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"abstract": "We develop a novel approach to chiral meson-baryon dynamics incorporating\nunitarity constraints and explicit resonance fields. It is based on the most\ngeneral structure of any pion-nucleon partial wave amplitude neglecting the\nunphysical cuts as derived from the N/D method. This amplitude is then matched\nto the one-loop heavy baryon chiral perturbation theory result at third order\nand to tree level exchanges of baryon- and meson states in the s,t and u\nchannels. This generates the left-hand cuts. The unitarization procedure does\nnot involve form factors or regulator functions. The resonance parameters are\ndetermined from fits to the S- and P-wave pion-nucleon partial wave amplitudes\nfor energies up to 1.3 GeV. In particular, the $\\Delta (1232)$ is accurately\nreproduced whereas scalar and vector meson couplings are less precisely pinned\ndown. We also obtain a satisfactory description of the $\\pi$N threshold\nparameters. Further extensions of this method to coupled channels and the\nthree-flavor case are briefly discussed.",
"arxiv_id": "nucl-th/9912026",
"authors": [
"Ulf-G. Mei\u00dfner",
"J. A. Oller"
],
"categories": [
"nucl-th",
"hep-ph"
],
"doi": "10.1016/S0375-9474(00)00150-0",
"journal_ref": "Nucl.Phys. A673 (2000) 311-334",
"title": "Chiral unitary meson-baryon dynamics in the presence of resonances: Elastic pion-nucleon scattering",
"url": "https://arxiv.org/abs/nucl-th/9912026"
},
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