Two- and four-quasiparticle states in the interacting boson model: Strong-coupling and decoupled band patterns in the SU(3) limit

Journal Article · Sat Sep 01 04:00:00 EDT 1990 · Physical Review, C (Nuclear Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevC.42.993· OSTI ID:6278796

Vretenar, D; Paar, V ^[1]; Bonsignori, G; Savoia, M ^[2]

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1. Prirodoslovno-matematicki Fakultet, University of Zagreb, 41000 Zagreb (Yugoslavia)
2. Istituto Nazionale di Fisica Nucleare, Sezione of Bologna and Department of Physics A. Righi'', Via Irnerio 46, Bologna (Italy)

An extension of the interacting boson approximation model is proposed by allowing for two- and four-quasiparticle excitations out of the boson space. The formation of band patterns based on two- and four-quasiparticle states is investigated in the SU(3) limit of the model. For hole-type (particle-type) fermions coupled to the SU(3) prolate (oblate) core, it is shown that the algebraic {ital K}-representation basis, which is the analog of the strong-coupling basis of the geometrical model, provides an appropriate description of the low-lying two-quasiparticle bands. In the case of particle-type (hole-type) fermions coupled to the SU(3) prolate (oblate) core, a new algebraic decoupling basis is derived that is equivalent in the geometrical limit to Stephens' rotation-aligned basis. Comparing the wave functions that are obtained by diagonalization of the model Hamiltonian to the decoupling basis, several low-lying two-quasiparticle bands are identified. The effects of an interaction that conserves only the total nucleon number, mixing states with different number of fermions, are investigated in both the strong-coupling and decoupling limits. All calculations are performed for an SU(3) boson core and the {ital h}11/2 fermion orbital.

• OSTI ID: 6278796
• Journal Information: Physical Review, C (Nuclear Physics); (USA), Journal Name: Physical Review, C (Nuclear Physics); (USA) Vol. 42:3; ISSN 0556-2813; ISSN PRVCA
• Country of Publication: United States
• Language: English

Related Subjects

653001* -- Nuclear Theory-- Nuclear Structure
Moments
Spin
& Models
73 NUCLEAR PHYSICS AND RADIATION PHYSICS
DEFORMED NUCLEI
ENERGY LEVELS
EVEN-EVEN NUCLEI
EXCITED STATES
INTERACTING BOSON MODEL
LIE GROUPS
MATHEMATICAL MODELS
MOMENT OF INERTIA
NUCLEAR MODELS
NUCLEI
QUASI PARTICLES
ROTATIONAL STATES
SHELL MODELS
SU GROUPS
SU-3 GROUPS
SYMMETRY GROUPS
YRAST STATES