Study of Baryon Excitations in Nuclei by Electromagnetic Interactions

1)介子产生之上的核有效相互作用：我们构建了一个新的形式，使我们能够构建原子核中重子和介子的有效相互作用，这似乎是传统核相互作用的自然延伸。其思想是通过幺正变换去除所有实过程中的虚交互作用。结果发现，单点交换势和静态双介子交换势与常规势一致。同时，我们得到了一般重子-重子势和介子-重子势，以及交换电磁电流。不含等压激励的交换电流与常规交换电流相同，而含等压激励的交换电流与重子-重子力一致。这种形式使我们能够研究原子核中的强电磁现象，包括介子的产生和湮灭过程。成功地研究了介子-核子散射的基本相互作用。并对p-p碰撞产生阈值中性介子进行了研究。目前，反应（pi, eta）， （gamma, eta）的研究正在进行中。2)介子-核反应：作为研究介子产生阈值以上电磁相互作用核反应的第一步，我们通过介子-核的弹性和电荷交换散射以及（3,3）共振周围的分析功率研究了等压线扩散势的性质。为此，我们给出了一种等压门态模型的形式，使我们能够研究开壳核的介子散射。通过研究^<12>C、^<13>C、^<15>N和^<16>O的介子散射，我们澄清了Lane项和自旋轨道项的存在，它们与能量无关。应当强调的是，这两个术语使我们能够正确地描述电荷交换散射的绝对大小和分析能力的标志。目前，基于该模型研究了p壳核在（3,3）共振周围产生的介子光。3)手性孤子夸克模型中的重子结构：在高动量转移核现象中，有效强子相互作用中的顶点函数结构是至关重要的。作为这方面的第一步，我们采用受QCD理论启发的SU(3)手性孤子夸克模型来研究重子的磁矩。通过将u（和/或d）和s之间的夸克质量差作为对称破缺项，我们得到了八重子的理论与实验的良好吻合，并且得到了与晶格计算相似的四重子的结果。这些结果表明该模型对于顶点函数的结构具有较高的可靠性。并成功地研究了哥德弗里德和。少

1) The nuclear effective interactions above the mesonproduction : We constructed a new formalism which enables us to construct the effective interaction of baryons andmesons in nuclei which seems a natural extension of the traditional nuclear interactions. The idea is to remove any virtual interactions at all the real processes by the unitary transformation. As a result, we found that our one-poin-exchange and static two-pion exchange potentials coincide with the conventional potentials. At the same time, we obtained general baryon-baryon and meson-baryon potentials, and the exchange electromagnetic currents. The exchange current which does not include isobar excitation is the same as the conventional one, and the current associated with isobar excitation is consistent with the baryon-baryon force. This formalism enables us to study the strong and electromagnetic phenomena in nuclei including the meson production and annihilation processes. The basic interaction for pion-nucleon scatte … More ring and pion photoproduction was successfully studied. Also threshold neutral pion production by p-p collision was studied. At present, study of the reactions (pi, eta), (gamma, eta) is in progress.2) Pion-nuclear reaction : As a first step toward the study of nuclear response by electromagentic interaction above mesonproduction threshold, we studied the properties of isobar spreading potential through the elastic and charge exchange pion-nucleus scattering and the analysing power around the (3,3) resonance. For this purpose, we gave a formalism of isobar-doorway state model which enables us to study the pion scattering by the open shell nuclei. By investigating pion scattering by ^<12>C,^<13>C,^<15>N and ^<16>O,we clarified existence of the Lane term as well as the spin-orbit term which are energy-independent. The enphasis should be placed on that these two terms allow us to describe correctly the absolute magnitude of charge-exchange scattering and also signs of analysing power. At present, pion-photoproduction on the p-shell nuclei around (3,3) resonance is under investigation based on the present model.3) Baryon Structure in chiral soliton quark model : Structure of vertex functions in the effective hadorn interaction is essentially important in the nuclear phenomena at high momentum transfer. As a first step for thsi, we studied magnetic moments of baryons by adopting the SU (3) chiral soliton quark model inspired by the QCD theory. By including quark-mass difference between u (and/or d) and s as a symmetry breaking term, we obtained a good agreement between the theory and the experiment for the Octet baryons, and also results for the Decuplet baryons similar to the lattice calculation. These results imply large reliability of the model for the structure of vertex function. Also the Godfried sum was studied successfully. Less