Structure and fragmentation of s-hole states in light nuclei

轻核中s-空穴态的结构和碎裂

基本信息

批准号：
08640394
负责人：
YAMADA Taichi
金额：
$ 1.22万
依托单位：
KANTO GAKUIN UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1998
项目状态：
已结题

项目摘要

We have studied the structure and fragmentation of s-hole states in light nuclei, which are related closely to the study of hypernuclei and the measurement of nucleon lifetime etc.・ SU(3) model for s-hole states and a selection ruleWe proposed the SU(3) model for s-hole states in light nuclei. This model is based on the fact that the s-hole state produced by the quasifree knockout reactions such as a ィイD1AィエD1Z(p, 2p) should have the same spatial symmetry as the ground state of the target nucleus, and the ground-state wave function of light nuclei is described well by the SU(3) nuclear wave function. The main results are given as follows : 1) The doorway-stage fragmentation process of the s-hole state in light nuclei is superior or competitive to the compound-stage one. 2) A selection rule is found for fragmentation of doorway s-hole states in light nuclei ; in the two-body fragmentation process of the doorway s-hole states, smaller fragments than the α particle are allowed, while the … More fragments such as the α particle and the larger particles are suppressed, in spite of the large Q value for the α fragment.・ Experiments on the fragmentation of ィイD111ィエD1B(s-hole) and ィイD115ィエD1N(s-hole) produced by the EィイD2pィエD2 = 392 MeV ィイD112ィエD1C, ィイD116ィエD1O(p, 2p) reactions at RCNP, Osaka UniversityThe two experiments were performed at RCNP (E81 and E110), and their analyses have been in progress now. The major results are given as follows. 1) The α fragmentation from the ィイD111ィエD1B(s-hole) and ィイD115ィエD1N(s-hole) states is found to be suppressed in comparison with the p, d and t ones, in spite of the large Q value of the α channel. This result is consistent with our prediction, and is not able to be explained with only the statistical model. 2) The s-hole state of ィイD111ィエD1B splits into three components to show the bump structure in the excitation spectrum of ィイD111ィエD1B. The three bumps have different branchingratios for p-, d-, t- and α-fragments.・ィイD112ィエD1C(p, 2p) excitation function with the 1hΩ shell modelIn order to study the origin of the bump structure, we analyzed the ィイD112ィエD1C(p, 2p) excitation function with the 1hΩ shell-model wave function. Reflecting the spatial symmetry of the target nucleus ィイD112ィエD1C with the main (second main) SU(3)[f](λμ) component [444](04) (([4431](12)), three SU(3) basis states of ィイD111ィエD1B, [443](04), [4421](04), [4421](12), are found to play an important role to produce the bump structure. This result indicated that the formation of the structure of the s-hole state in the ィイD1AィエD1Z(p, 2p) excitation function is attributed to the spatial symmetry of the target nucleus. This is due to the characteristic of the quasifree knockout reaction. Less

我们研究了轻核中s-hole态的结构和碎裂，这与超核研究和核子寿命测量等密切相关。s-hole态SU(3)模型和选择规则我们提出了SU(3)s-hole态模型和选择规则(3) 轻核中的 s 空穴态模型该模型基于准自由敲除反应（例如 D1A D1Z(p, 2p)应与目标核的基态具有相同的空间对称性，并且SU(3)核波函数很好地描述了轻核的基态波函数，主要结果如下： 1)轻核中s-空穴态的门口级碎裂过程优于或有竞争力2)轻核中s-空穴态门口级碎裂的选择规则；门道破碎过程在 s 空穴态中，允许存在比 α 粒子更小的碎片，而尽管 α 碎片的 Q 值很大，但诸如 α 粒子和较大粒子之类的碎片被抑制。・ED2pD2 = 392 MeV 产生的 D111D1B(s-hole) 和 D115D1N(s-hole)大阪大学 RCNP 的 D112D1C、D116D1O(p, 2p) 反应两个实验在 RCNP（E81 和 E110）进行，目前主要结果如下： 1) 来自 RCNP 的 α 断裂。 D111D1B（s孔）和尽管 α 通道的 Q 值很大，但发现 D115D1N(s-hole) 态与 p、d 和 t 态相比受到抑制。这个结果与我们的预测一致，并且无法解释。仅使用统计模型 2) D111D1B 的 s 孔状态分为三个分量以显示激发谱中的凸块结构。 D111D1B。这三个凸块对于p-、d-、t-和α-片段具有不同的分支比。具有1hΩ壳模型的D112D1C(p,2p)激励函数为了研究凸块结构的起源，我们分析了D112D1C。 1hΩ 壳模型的 (p, 2p) 激励函数反映目标核 D112D1C 与主（第二主）SU(3)[f](λμ) 分量 [444](04) (([4431](12)) 、三个 SU(3) 的空间对称性。 ) D111D1B 的基本状态，[443](04)，[4421](04)， [4421](12)，被发现对产生凹凸结构起着重要作用，这一结果表明D1A(p,2p)激发函数中s-hole态结构的形成归因于空间。这是由于准自由敲除反应的特征。