Three-Body Binding and Resonant Mechanisms in Neutron-Rich Light Nuclei Far from Stability Line

Shigeyoshi Aoyama, Kiyoshi Katō, Kiyomi Ikeda
2001 Progress of Theoretical Physics Supplement  
We study the typical Borromean systems of 4 He+n+n for 6 He and of 9 Li+n+n for 11 Li. In addition to these three body systems, we investigate the 8 He+n+n ground resonance state in 10 He. In understanding the binding mechanism of these loosely or unbound systems of the core+two valence neutrons, it is shown that the pairing correlation between valence neutrons becomes important. For the excited resonance states in 6 He and for the ground resonance state in 10 He, we extensively use the complex
more » ... ely use the complex scaling method (CSM) to solve the three body resonance problems. The CSM is shown to be very useful not only for analysis of the observed 2 + state in 6 He and the ground state in 10 He but also for prediction of three new 2 + 2 , 1 + 1 and 0 + 2 resonance states in 6 He. These results present that the core+n+n model explains characteristic properties of 6 He. On the other hand, we discuss that a 9 Li+n+n model for 11 Li is not so simple as the 6 He case. To solve the binding energy problem, the 9 Li-n interaction is investigated in detail. Our much interest is concentrated on the the pairing correlation not only between valence neutrons but also between neutrons in the 9 Li-core. By taking into account pairing configurations in addition to the simple neutron (p 3/2 )-closed configuration, we show that the pairing blocking effect of core neutrons plays a very important role in understanding the low-lying single particle s-state in 10 Li and the strong state-depending 9 Li-n interaction. As a possibility of the experimental checking for the low-lying s-state in 10 Li, we discuss the observation of the so-called Thomas-Ehrman shift in the mirror nucleus 10 N, which has not been observed yet.
doi:10.1143/ptps.142.35 fatcat:rpbs2cizhbd2bponufsympdlxy