Modification of tensor force in 0p-shell model effective interaction

In many shell model interactions, the tensor force monopole matrix elements often retain systematic trends originating in the bare tensor force. However, in this work, we find that Isospin [Formula: see text] tensor force monopole matrix elements of widely used p-shell effective interaction CK(8–16) do not share these systematic. We correct these discrepancies by modifying [Formula: see text] tensor force two-body matrix elements (TBMEs) of CK(8–16) by the analytically calculated tensor force TBMEs. With some additional modification of single-particle energies and TBMEs, the revised effective interaction is named as CKN. The effective interaction CKN has been tested for the calculations of p-shell nuclei of normal parity states from various physics viewpoints such as excitation spectra, electromagnetic moments, and electromagnetic and Gamow–Teller (GT) transitions. The obtained results are found to be satisfactory with respect to the experimental results.

A NEW MICROSCOPIC VIEW OF NUCLEAR DEFORMATION

The microscopic origin of deformation for heavy nuclei is discussed. Evidence is presented that the systematic features of nuclear deformation are determined primarily by filling of the normal-parity shell model orbitals of the valence shells, and that the abnormal-parity orbitals play crucial but subsidiary roles. This is in accord with the point of view underlying the Fermion Dynamical Symmetry Model. In addition, we demonstrate that the deformation systematics of the FDSM are consistent with those of the Nilsson model, despite their very different starting points, and that the assumptions of the FDSM are consistent with the assertion that the n-p quadrupole-quadrupole residual interaction is the essential reason for deformation. Finally, application of the same principles to superdeformation suggests that abnormal parity orbitals have a much more direct influence on superdeformation than on normal deformation.

Symmetry and the Origin of Nuclear Deformation

Evidence is presented that the systematic features of nuclear deformation are determined primarily by filling of the normal-parity shell model orbitals of the valence shells, and that abnormal-parity orbitals play important but sec ondary roles in the microscopic origin of deformation. This contradicts many common ideas concerning deformation, but is in accord with the point of view underlying the Fermion Dynamical Symmetry Model. We argue that the deformation systematics of the FDSM and the Nilsson model are mutually consistent, and that in the FDSM the n−p quadrupole residual interaction is responsible for deformation. The same principles applied to superdeformation indicate that abnormal parity orbitals have a much more direct influence on superdeformation than on normal deformation.