dorsal/arxiv
View SchemaAnalysis of eta production using a generalized Lee model
| Authors | J. Denschlag, L. Tiator, D. Drechsel |
|---|---|
| Categories | |
| ArXiv ID | nucl-th/9802063 |
| URL | https://arxiv.org/abs/nucl-th/9802063 |
| DOI | 10.1007/s100500050164 |
| Journal | Eur.Phys.J. A3 (1998) 171-181 |
Abstract
We have investigated the processes N($\pi$, $\pi$)N and N($\pi$, $\eta$)N close to eta threshold using a simple, nonrelativistic Lee model which has the advantage of being analytically solvable. It is then possible to study the Riemann sheets of the S-matrix and the behavior of its resonance poles especially close to threshold. A theoretical simulation of the experimental cusp effect at eta threshold leads to a characteristic distribution of poles on the Riemann sheets. We find a pole located in the $4^{th}$ Riemann sheet that up to now has not been discussed. It belongs to the cusp peak at eta threshold. In addition we obtain the surprising result using the Lee model that the resonance $S_{11}(1535)$ does not play a large role. The main features of the experimental data can be reproduced without explicitly introducing this resonance. Furthermore, we have also studied the reactions N($\gamma$, $\pi$)N and N($\gamma$, $\eta$)N and find reasonable agreement between the data and both models with and without the $S_{11}(1535)$ resonance.
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"abstract": "We have investigated the processes N($\\pi$, $\\pi$)N and N($\\pi$, $\\eta$)N\nclose to eta threshold using a simple, nonrelativistic Lee model which has the\nadvantage of being analytically solvable. It is then possible to study the\nRiemann sheets of the S-matrix and the behavior of its resonance poles\nespecially close to threshold. A theoretical simulation of the experimental\ncusp effect at eta threshold leads to a characteristic distribution of poles on\nthe Riemann sheets. We find a pole located in the $4^{th}$ Riemann sheet that\nup to now has not been discussed. It belongs to the cusp peak at eta threshold.\nIn addition we obtain the surprising result using the Lee model that the\nresonance $S_{11}(1535)$ does not play a large role. The main features of the\nexperimental data can be reproduced without explicitly introducing this\nresonance. Furthermore, we have also studied the reactions N($\\gamma$, $\\pi$)N\nand N($\\gamma$, $\\eta$)N and find reasonable agreement between the data and\nboth models with and without the $S_{11}(1535)$ resonance.",
"arxiv_id": "nucl-th/9802063",
"authors": [
"J. Denschlag",
"L. Tiator",
"D. Drechsel"
],
"categories": [
"nucl-th"
],
"doi": "10.1007/s100500050164",
"journal_ref": "Eur.Phys.J. A3 (1998) 171-181",
"title": "Analysis of eta production using a generalized Lee model",
"url": "https://arxiv.org/abs/nucl-th/9802063"
},
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