Density-induced suppression of the {alpha}-particle condensate in nuclear matter and the structure of {alpha}-cluster states in nuclei
- Nishina Center for Accelerator-Based Science, The Institute of Physical and Chemical Research (RIKEN), Wako, Saitama 351-0198 (Japan)
- Research Center for Nuclear Physics (RCNP), Osaka University, Osaka 567-0047 (Japan)
- Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany)
- Institut de Physique Nucleaire, F-91406 Orsay Cedex (France)
- Laboratory of Physics, Kanto Gakuin University, Yokohama 236-8501 (Japan)
At low densities, with decreasing temperatures, in symmetric nuclear matter {alpha} particles are formed, which eventually give raise to a quantum condensate with four-nucleon {alpha}-like correlations (quartetting). Starting with a model of {alpha} matter, where undistorted {alpha} particles interact via an effective interaction such as the Ali-Bodmer potential, the suppression of the condensate fraction at zero temperature with increasing density is considered. Using a Jastrow-Feenberg approach, it is found that the condensate fraction vanishes near saturation density. Additionally, the modification of the internal state of the {alpha} particle due to medium effects will further reduce the condensate. In finite systems, an enhancement of the S-state wave function of the center-of-mass orbital of {alpha}-particle motion is considered as the correspondence to the condensate. Wave functions have been constructed for self-conjugate 4n nuclei that describe the condensate state but are fully antisymmetrized on the nucleonic level. These condensate-like cluster wave functions have been successfully applied to describe properties of low-density states near the n{alpha} threshold. Comparison with orthogonality condition model calculations in {sup 12}C and {sup 16}O shows strong enhancement of the occupation of the S-state center-of-mass orbital of the {alpha} particles. This enhancement is decreasing if the baryon density increases, similar to the density-induced suppression of the condensate fraction in {alpha} matter. The ground states of {sup 12}C and {sup 16}O show no enhancement at all, thus a quartetting condensate cannot be formed at saturation densities.
- OSTI ID:
- 21191940
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 77, Issue 6; Other Information: DOI: 10.1103/PhysRevC.77.064312; (c) 2008 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
- Country of Publication:
- United States
- Language:
- English
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