arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 0806.2043nucl-th
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介子-核子反应共振态的提取

Extraction of Resonances from Meson-Nucleon Reactions

N. Suzuki, T. Sato, T. -S. H. Lee

摘要:

我们提出了一个教学研究的常用的速度图(SP)和时间延迟(TD)的方法提取共振参数从两个粒子耦合通道反应的数据。在几个精确可解的模型中,发现这两种方法在不同的黎曼面上找到极点,并不总是有效的。然后,我们开发了一个解析延拓方法提取内的$πN$和$γN$反应的动态耦合通道配方的核子共振。主要重点是解决由于与不稳定的$πΔ, ρN, σN$通道耦合而引起的并发症,这些通道衰减为$ππN$状态。通过使用所考虑的精确可解模型的结果,显式数值计算程序,并验证。作为第一个应用程序开发的解析延拓方法,我们提出了核子共振的$S_{11}$和$S_{31}$内最近开发的耦合通道模型$πN$反应提取的分波。从这个现实的$πN$模型,其中包括$πN$,$ηN$,$πΔ$,$ρN$,和$σN$通道的结果,也表明,简单的极点参数化的谐振传播使用从SP和TD方法提取的极点效果不佳。

英文摘要:

We present a pedagogical study of the commonly employed Speed-Plot (SP) and Time-delay (TD) methods for extracting the resonance parameters from the data of two particle coupled-channels reactions. Within several exactly solvable models, it is found that these two methods find poles on different Riemann sheets and are not always valid. We then develop an analytic continuation method for extracting the nucleon resonances within a dynamical coupled-channel formulation of the $πN$ and $γN$ reactions. The main focus is on resolving the complications due to the coupling with the unstable $πΔ, ρN, σN$ channels which decay into $ππN$ states. By using the results from the considered exactly solvable models, explicit numerical procedures are presented and verified. As a first application of the developed analytic continuation method, we present the nucleon resonances in the $S_{11}$ and $S_{31}$ partial waves extracted within a recently developed coupled-channels model of $πN$ reactions. The results from this realistic $πN$ model, which includes $πN$, $ηN$, $πΔ$, $ρN$, and $σN$ channels, also show that the simple pole parametrization of the resonant propagator using the poles extracted from SP and TD methods works poorly.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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