2005 Fiscal Year Final Research Report Summary
Study of Many-Particle Correlation in Structure and Reactions of Light Exotic Nuclei
| Project/Area Number |
14540249
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
素粒子・核・宇宙線
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| Research Institution | Niigata University |
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Principal Investigator |
SUZUKI Yasuyuki Niigata University, Institute of Science and Technology, Professor, 自然科学系, 教授 (70018670)
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| Project Period (FY) |
2002 – 2005
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| Keywords | Halo nucleus / Hyper nucleus / quark model / cluster model / eikonal approximation / breakup / carbon isotopes / reaction cross sections |
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| Research Abstract |
We summarize the results according to the main subjects of research.
1.Study of many-particle correlation in unstable nuclei
A mechanism for suppressing the electric E2 transition from the excited state to the ground state in 16C was studied in a 14C+n+n model. The correlated motion of the two neutrons, which interact via a realistic potential, was taken into account fully. The role of spin-triplet component in the suppression mechanism was clarified. A comparison with experiment showed that the assumption of shell closure for 14C may not be perfect but one has to consider the possibility of including the core excitation to some extent, in order to obtain more complete understanding of the issue together with the E2 transition in 15C.
2.Study of reaction mechanism with unstable nuclei
A computer code was developed to facilitate a calculation of various reaction cross sections induced by unstable nuclei, which is assumed to consist of a core nucleus and a valence neutron. The cross sections
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which are calculable cover the elastic scattering including the breakup effects of the nucleus and the momentum distribution of the core after the breakup. The basic theory employed was an eikonal approximation. To make the eikonal approximation applicable for a heavy target such as 208Pb, a divergence-free amplitude had to be incorporated in the theory. This was performed combining the eikonal model with the perturbation theory of the Coulomb excitation.
A feasibility of a complete calculation of the Glauber multiple scattering amplitude was demonstrated with the use of Monte Carlo integration technique. This technique will open a way to describe high-energy reactions using correlated wave functions of high accuracy.
3.Study of the binding mechanism of light hypernuclei and the baryon-baryon interactions
A long-standing problem of A=3-5 Λ hypernuclei, the overbinding observed in the systematics of the ground state energies, were resolved by taking into account the ΛΣ coupling explicitly. The tensor force played an essential role in this problem. Larger systems such as ^9_ΛBe and ^6_<ΛΛ>He were studied with the potentials derived from a quark-model developed by Kyoto-Niigata group. In this study, a new framework was developed in order to make the application of the non-local, energy-dependent quark-model potentials possible in structure calculations. Less
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