Concepts of nuclear {alpha}-particle condensation

Journal Article · Tue Dec 15 00:00:00 EST 2009 · Physical Review. C, Nuclear Physics

DOI:https://doi.org/10.1103/PHYSREVC.80.064326· OSTI ID:21296591

Funaki, Y ^[1]; Horiuchi, H ^[2]; Oertzen, W von ^[3]; Roepke, G ^[4]; Schuck, P ^[5]; Tohsaki, A ^[2]; Yamada, T ^[6]

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1. Institute of Physics, University of Tsukuba, Tsukuba 305-8571 (Japan)
2. Research Center for Nuclear Physics, Osaka University, Osaka 567-0047 (Japan)
3. Hahn-Meitner-Institut Berlin, Glienicker Strasse 100, D-14109 Berlin (Germany)
4. Institut fuer Physik, Universitaet Rostock, D-18051 Rostock (Germany)
5. Institut de Physique Nucleaire, F-91406 Orsay CEDEX (France)
6. Laboratory of Physics, Kanto Gakuin University, Yokohama 236-8501 (Japan)

Certain aspects of the recently proposed antisymmetrized {alpha}-particle product state wave function, or THSR (Tohsaki-Horiuchi-Schuck-Roepke) {alpha}-cluster wave function, for the description of the ground state in {sup 8}Be, the Hoyle state in {sup 12}C, and analogous states in heavier nuclei are elaborated in detail. For instance, the influence of antisymmetrization in the Hoyle state on the bosonic character of the {alpha} particles is studied carefully. It is shown to be weak. Bosonic aspects in Hoyle and similar states in other self-conjugate nuclei are, therefore, predominant. Another issue is the de Broglie wavelength of {alpha} particles in the Hoyle state, which is shown to be much larger than the inter-{alpha} distance. It is pointed out that the bosonic features of low-density {alpha} gas states have measurable consequences, one of which, enhanced multi-{alpha} decay properties, has likely already been detected. Consistent with experiment, the width of the proposed analog to the Hoyle state in {sup 16}O at the excitation energy of E{sub x}=15.1 MeV is estimated to be very small (34 keV), lending credit to the existence of heavier Hoyle-like states. The intrinsic single-boson density matrix of a self-bound Bose system can, under physically desirable boundary conditions, be defined unambiguously. One eigenvalue then separates out, being close to the number of {alpha} particles in the system. Differences between Brink and THSR {alpha}-cluster wave functions are worked out. No cluster model of the Brink type can describe the Hoyle state with a single configuration. On the contrary, many superpositions of the Brink type are necessary, implying delocalization toward an {alpha}-product state. It is shown that single {alpha}-particle orbits in condensates of different nuclei are almost the same. It is thus argued that {alpha}-particle (quartet) antisymmetrized product states of the THSR type are a very promising novel and useful concept in nuclear physics.

• OSTI ID: 21296591
• Journal Information: Physical Review. C, Nuclear Physics, Vol. 80, Issue 6; Other Information: DOI: 10.1103/PhysRevC.80.064326; (c) 2009 The American Physical Society; Country of input: International Atomic Energy Agency (IAEA); ISSN 0556-2813
• Country of Publication: United States
• Language: English

Related Subjects

73 NUCLEAR PHYSICS AND RADIATION PHYSICS
ALPHA DECAY
ALPHA PARTICLES
BERYLLIUM 8
BOSONS
BOUNDARY CONDITIONS
CARBON 12
CLUSTER MODEL
CONDENSATES
CONFIGURATION
DE BROGLIE WAVELENGTH
DENSITY MATRIX
EIGENVALUES
EXCITATION
GROUND STATES
HEAVY NUCLEI
MEV RANGE 10-100
NUCLEAR PHYSICS
OXYGEN 16
WAVE FUNCTIONS