On the existence of N*(890) resonance in S 11 channel of πN scatterings
Low-energy partial-wave πN scattering data is reexamined with the help of the production representation of partial-wave S matrix, where branch cuts and poles are thoroughly under consideration. The left-hand cut contribution to the phase shift is determined, with controlled systematic error estimate...
| Autores: | , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión enviada para evaluación y publicación |
| Fecha de publicación: | 2019 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/208798 |
| Acceso en línea: | http://hdl.handle.net/10261/208798 |
| Access Level: | acceso abierto |
| Palabra clave: | Dispersion relations N scatterings nucleon resonance |
| Sumario: | Low-energy partial-wave πN scattering data is reexamined with the help of the production representation of partial-wave S matrix, where branch cuts and poles are thoroughly under consideration. The left-hand cut contribution to the phase shift is determined, with controlled systematic error estimates, by using the results of O(p) chiral perturbative amplitudes obtained in the extended-onmass- shell scheme. In S and P channels, severe discrepancies are observed between the phase shift data and the sum of all known contributions. Statistically satisfactory fits to the data can only be achieved by adding extra poles in the two channels. We find that a S resonance pole locates at zr = (0:895–0:081)–(0:164–0:023)i GeV, on the complex s-plane. On the other hand, a P virtual pole, as an accompanying partner of the nucleon bound-state pole, locates at zv = (0:966–0:018) GeV, slightly above the nucleon pole on the real axis below threshold. Physical origin of the two newly established poles is explored to the best of our knowledge. It is emphasized that the O(p) calculation greatly improves the fit quality comparing with the previous O(p) one. |
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