Comparison of local, semi-microscopic, and microscopic three-cluster models
- Physique Quantique, C.P. 165/82, Universite Libre de Bruxelles, B 1050 Brussels (Belgium)
- Physique Nucleaire Theorique et Physique Mathematique, C.P. 229, Universite Libre de Bruxelles, B 1050 Brussels (Belgium)
Two different three-body models are compared with a fully antisymmetrized microscopic three-cluster model. The local model makes use of local effective interactions involving forbidden states among the three particles. In the semi-microscopic model, nonlocal two-body interactions are derived within the resonating-group method from the same nucleon-nucleon effective forces as in the microscopic model. In both cases, calculations are performed in hyperspherical coordinates with the Lagrange-mesh method. The role of forbidden states and their elimination are discussed. The models are applied to an {alpha}{alpha}n description of {sup 9}Be and an {alpha}nn description of {sup 6}He. The local model results are affected by almost forbidden states and may be unrealistic for {sup 9}Be. A comparison of the microscopic and semi-microscopic models shows that the effect of exchanges involving the three clusters is weak. An overbinding of {sup 9}Be cannot be avoided with nucleon-nucleon forces reproducing {alpha}n and {alpha}{alpha} scattering properties. On the contrary, {sup 6}He is underbound under the same conditions. This can probably be attributed to a lack of three-nucleon forces.
- OSTI ID:
- 20863847
- Journal Information:
- Physical Review. C, Nuclear Physics, Vol. 74, Issue 4; Other Information: DOI: 10.1103/PhysRevC.74.044304; (c) 2006 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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