Limit Of Interacting Boson Model Research Articles

E2 selection rules of γ-rigid and γ-unstable rotors

It has been known that the E2 selection rules are similar between the Davydov-Filippov rigid triaxial rotor model with γ = 30° and the O(6) limit of the interacting boson model (IBM). Using the O(6) limit of IBM, we investigate the relationship of the wavefunctions of O(6) and those of the Davydov-Filippov model. We introduce an intrinsic state with a fixed γ-value and construct its intrinsic excitation. It was shown by Ginocchio and Kirson that the O(6) wavefunctions can be expressed using the intrinsic state by the integration with respect to the γ-value. A formula is given which expresses the O(6) wavefunctions as a superposition of the γ-fixed intrinsic state and its intrinsic excitation. A discrete symmetry of these intrinsic excitations has been found, and by using this symmetry, we analyze the close connection between the E2 selection rules of the Davydov-Filippov rotor model and the O(6) limit of IBM.

The effective quadrupole force between like IBA-bosons

It is shown that an effective quadrupole interaction between like bosons in the Interacting Boson Model (IBM) arises from the neutron-proton quadrupole force as a consequence of the truncation of the full shell-model space to the SD sub-space. The strength of this effective interaction vanishes in the SU(5) limit of IBM but is appreciable in the SU(3) and O(6) limits and thus can give rise to the occurrence of an SU(3) symmetry.