Study of Electron-Nucleus Scattering and Nuclear Electromagnetic Properties Based on Microscopic IBM (Ⅱ) Theoretical Approach Based on ME Method

Abstract：

In this paper a mapping of the collective state subspace in a microscopic IBM onto the fermion collective state subspace is achieved. A microscopic theoretical method (ME method),which is suitable to deduce the boson one-body operator from the fermion one body operator,is proposed by supposing the form of the boson operator and making equal the matrix elements of physical operator between the coressponding normal basis vectors of the two different collective state subspaces. In the context, the procedure of obtaining the boson structure function,i.e. the determination of the boson transition charge/current density operator,is taken as an example to give a detailed statement of the method. Thereafter, calculations of the nuclear charge/current densities can be carried out in the boson state space by taking advantage of the eigenfuncitons of the microscopic IBM. Associated with the formal theories of electron nucleus scattering and nuclear electromagnetic transition,a microscopic approach,which can be used to study nuclear transition charge/current densities,various form factors,differential cross sections,reduced transition rates,electromagnetic multipole moments, g factors, and so on,can be built up. Preliminary calculations of transition charge density and reduced transition probability from 2+1 to 0+1 in ¹⁴⁶Nd are carried out in terms of the approach in the framework of microscopic sdgIBM 1. It is found that the theoretical results fit the experimental data quite well.