Theory of Meson Production on the Nucleon by Resonance Excitation

该项目旨在通过对入射通道中的强子探针和光子散射数据的分析来确定核子共振参数（质量，特别是耦合强度）。将使用gee ßen耦合通道k矩阵模型来计算光子和介子诱导反应同时通过共振激发产生介子的振幅。初等顶点由采用有效拉格朗日的有效场论模型来描述。背景贡献一致地从相同的拉格朗日量计算，从而最小化了自由参数的数量。作为Gießen模型的一个重大升级，我们将特别注意改进由SU(3)-味0-八元体形成的相关2介子通道的处理。研究结果将对有效场论中的多介子动力学以及重子-重子相互作用中的t通道和u通道介子交换过程具有重要意义。将研究电子和中微子对介子产生的扩展。

The project aims at the determination of nucleon resonance parameters (masses and, in particular, coupling strengths) from an analysis of scattering data, both with hadronic probes and photons in the incoming channel. The Gießen coupled channels K-matrix model will be used to calculate the amplitudes for meson production through resonance excitation simultaneously for photon- and meson-induced reactions. The elementary vertices are described by effective field theoretical models employing an effective Lagrangian. The background contributions are consistently calculated from the same Lagrangian thus minimizing the number of free parameters. As a major upgrade of the Gießen Model special attention will be paid to improve the treatment of the correlated 2-meson channels which can be formed from the fundamental SU(3)-flavor 0- octet. The results will be of relevance for multi-pion dynamics in effective field theories and in t- and u-channel meson exchange processes in baryon-baryon interactions. Extensions to meson production by electrons and neutrinos will be investigated.