STUDY OF SPIN-ISOSPIN AND DELTA MODES IN INTERMEDIATE NUCLEAR REACTIONS

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1. Isospin-spin modes excitation in quasi-elastic scattering region(1) Isospin-spin modes are studied by quasi-elastic(p,n)reactions in collaboration with experimentalists in LAMPF.We made model calculation by DWIA and continuum RPA with orthogonality condition. The observed ratio of the spin longitudinal to transverse response functions implies week RPA type correlations in the high momentum transfer region.(2) A more reliable method than before is proposed for extracting spin response functions from observed polarization transfers. It is based on PWIA and optimal factorization for the t matrix.(3) Difference between the ordinary continuum RPA and the one with orthogonality condition is clarified and importance of the condition is numerically studied.(4) The universality condition for the g parameters of the short range correlation is relaxed and their dependence of spin response functions are studied.(5) We calculated the spin longitudinal and transverse response functions of deutero … More n which are standard for the analysis of the nuclear response functions. Their ratio is found considerably energy dependent,which had been considered to be unity.2. DELTA-isobar excitation(1) A collective-coordinate quantization method for 1+1 dimensional soliton models are proposed to derive Born terms for meson-soliton scattering. The quantized Hamiltonian does not possess the Yukawa coupling but the linear and quadratic meson soliton interactions which reproduce rigorously the Born term for meson-soliton scattering. This method was applied to the Skyrme model to derive the Born terms for pion nucleon elastic scattering and pion photoproduction.(2) Various problems were investigated concerning the quantization of gauge field theories in a finite box constrained by the periodic boundary conditions. We used a unitary transformation method to eliminate unphysical degrees of freedom in the Weyle gauge Hamiltonian. We obtained the quantized Hamiltonian which contains zero modes as important physical degrees of freedom.(3) Electromagnetic,axial-vector,and strong off-shell form factors are introduced consistently with the PCAC hypothesis and gauge invariance. We showed that the divergence of the off-shell electromagnetic form factors in the chiral limit entails a modification of the celebrated low-energy theorem for the pion photoproduction. Less