Experimental study of vanishing of N=20 magicity in neutron rich nuclei

富中子核中N=20魔力消失的实验研究

• 批准号: 15540271
• 负责人: IZUMI Hideaki
• 金额: $ 2.3万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15540271/
• 关键词: nuclear structure; unstable nuclei; neutron-rich nuclei; beta decay; spin polarization; parit; excited state; beta asymmetry; 殻模型; 中性子; γ線; 核分光

The excited states in the light neutron-rich nucleus ^<11>Be have been studied through the β-delayed neutron- and γ -decays from spin-polarized ^<11>Li_<g.s>.. The experiment is based on the new method in the β-delayed decay spectroscopy from a spin polarized nucleus, ^<11>Li_<g.e.>(β)→11Be(n)→^<10>Be^* (γ)→^<10>Be_<g.e.>, to unambiguously assign the spins and parities of the states populated in β-decay., by taking advantage of the fact that the allowed B-decay from a polarized nucleus shows an angular distribution of W(θ) 〜1 + AP cosθ, which depends on the spin value of the daughter state. Here, θ, A and P are the emission angle with respect to the polarization axis, the asymmetry parameter of β-transition and the polarization of the parent nucleus, respectively.The level scheme and decay scheme of ^<11>Be^* were established from the β-γ, β-n and β-n-γcoincidences, and the spins and parities for 7 levels in ^<11>Be were firmly assigned from the βdecay asymmetries measured in coincidence with the delayed radiations. The neutron-spectroscopic factors of the levels in ^<11>Be were also determined. Some of the levels show good accord with predictions by the anti-symmetrized molecular dynamics (AMD) theory, which predicts various types of 2α-cluster states in the rotational bands and a single α-cluster state.

本文<11>利用自旋极化的轻丰中子核^ Li的β缓发中子和γ衰变研究了轻丰中子核^<11><g.s>Be的激发态。本实验是基于自旋极化核^<11>Li_<g.e.>（β）→11Be（n）→^<10>Be^*（γ）→^<10>Be_<g.e.>的β延迟衰变谱的新方法，明确地指定β衰变中布居态的自旋和宇称。利用极化核B衰变的角分布为W（θ）&lt;$1 + AP cosθ，它依赖于子态的自旋值.其中θ、A和P分别是β跃迁的不对称参数和母核的极化，<11>β-γ、β-n和β-n-γ符合建立了^ Be^* 的能级和衰变方案，<11>β衰变不对称性与延迟辐射的符合确定了^ Be中7个能级的自旋和宇称。还测定了^ Be能级的中子分光因子<11>。其中一些能级与反对称分子动力学（AMD）理论的预言有很好的雅阁，AMD理论预言转动带中存在多种2α团簇态和一个α团簇态.

项目成果

Structure of 11Be studied in β-delayed neutron- and γ-decay from polarized 11Li

在极化 11Li 的 β 延迟中子和 γ 衰变中研究 11Be 的结构

• 发表时间: 2004
• 期刊: Nucl. Phys. A746
• 作者: A.Odahara;et al.;Y Hirayama et al.
• 通讯作者: Y Hirayama et al.

Study of ^<11>Be structure through β-delayed decays from polarized ^<11>Li

通过极化 ^<11>Li 的 β 延迟衰变研究 ^<11>Be 结构

• 发表时间: 2005
• 期刊: Physics Letter B 611
• 作者: Hiroyuki Hata;Hiroyuki Hata;Masako Fujita;Y.Hirayama
• 通讯作者: Y.Hirayama

Spectroscopic study of 11Be through β-delayed neutron- and γ-decays of spin-polarized 11Li

通过自旋极化 11Li 的 β 延迟中子和 γ 衰变对 11Be 进行光谱研究

• 发表时间: 2004
• 期刊: Nuclear Physics A 738
• 作者: H.Miura;T.Nakamoto;H.Hirayama et al.
• 通讯作者: H.Hirayama et al.

「研究成果報告書概要(和文)」より

摘自《研究结果报告摘要（日文）》

• 发表时间: 2005
• 作者: Kawauchi;et. al.;Nishimura et al.;Dezawa et al.;Yoshizawa et al.;星野 幹雄;星野 幹雄
• 通讯作者: 星野 幹雄