1. National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA;2. Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA;3. Department of Physics, The Ohio State University, Columbus, OH 43210, USA;4. Institut für Kernphysik, Technische Universität Darmstadt, 64289 Darmstadt, Germany;5. ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung GmbH, 64291 Darmstadt, Germany;6. Center for Nuclear Study, Graduate School of Science, University of Tokyo, Hongo, Tokyo, 113-0033, Japan;1. National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000, USA;2. Department of Physics & Astronomy, McMaster University, Hamilton, Ontario L8S 4M1, Canada;3. Department of Physics, Central Michigan University, Mount Pleasant, MI 48859, USA;1. Triangle Universities Nuclear Laboratory, Durham, NC 27708-0308, United States;2. Department of Physics, North Carolina State University, Raleigh, NC 27695-8202, United States;3. Department of Physics, Duke University, Durham, NC 27708-0305, United States;4. Department of Physics and Astronomy, Georgia State University, Atlanta, GA 30303, United States
Abstract:
We examine parity-mixed configurations with j =32 role=presentation style=font-size: 90%; display: inline-block; position: relative;> using a four-particle model, whose complete solution can be calculated exactly with arbitrary interaction. Only the residual interaction is varied, and this is simulated as a sum of the one-pion-exchange-force (OPEP) and an attractive δ-force. As the OPEP is made stronger, a 0− state comes down to the ground state. Then the ground state can be described in terms of a Hartree-Fock (HF) ansatz with parity mixing. On the other hand, as the attractive central force is strengthened, the 0− state goes up in energy, and the spectrum becomes very similar to the experimental spectrum of 16O. This fact indicates the possible importance of the considered parity-mixed configurations for certain excited states of nuclei. In the δ-force case, the ground state cannot be well approximated by any quite general HF state. But within the framework of a normal pairing (BCS) ansatz, it is well reproduced.
