2003 Fiscal Year Final Research Report Summary
Neutron Halo Structure in exiotic nuclei (^<17>B,^<22>N,^<23>O etc.)
| Project/Area Number |
13440075
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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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 | Saitama University (2003)
Niigata University (2001-2002) |
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Principal Investigator |
SUZUKI Takeshi Saitama University, Science, Professor, 理学部, 教授 (10196842)
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| Co-Investigator(Kenkyū-buntansha) |
IZUMIKAWA Takashi NIIGATA University, RI Center, Research Associate, アイソトープ総合センター, 助手 (60282985)
OHTSUBO Takashi NIIGATA University, Science, Research Associate, 理学部, 助手 (70262425)
YOSHINAGA Naotaka Saitama University, Science, Professor, 理学部, 教授 (00192427)
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| Project Period (FY) |
2001 – 2003
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| Keywords | Neutron Halo / Skin structure / Momentum distribution / Glauber model / Shell mixing / Reaction cross section / Density distribution |
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| Research Abstract |
The two--neutron removal cross section (σ_<-2n>) and the longitudinal momentum distribution of ^<15>B fragments from the breakup of ^<17>B on ^9Be were measured at 70 A MeV. The distribution in the projectile rest frame is characterized by a FWHM of 80±10 MeV/c for ^<15>B. The σ_<-2n> is found to be 0.22±0.05 b. A Glauber--type analysis of the data provides clear evidence of a two-neutron halo structure in ^<17>B.
The reaction cross section (σ_R) for the neutron-rich nucleus ^<17>B on a carbon target has been measured at an energy of 77 AMeV by a transmission method. A large enhancement of σ_R was observed (1400mb). The density distribution of ^<17>B was deduced through the energy dependence of σ_R together with high-energy data using a finite-range Glauber model calculation under an optical limit approximation. It is confirmed that the neutron-tail in the density distribution is necessary for ^<17>B in order to reproduce the measured σ_R. Based on the assumption of a core (^<15>B) plus valence two-neutron picture, the mixture of v (2s_<1/2>) and v (1d_<5/2>) was studied without treating the correlation between two neutrons.
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