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STUDY OF NUCLEAR INTERACTIONS BY PRECISE MEASUREMENT OF POLARIZATION OBSERVABLES IN FEW-NUCLEON SYSTEMS

少核子系统中偏振观测值的精密测量研究核相互作用

基本信息

批准号：
03452023
负责人：
SAGARA Kenshi
金额：
$ 4.35万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1993
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-03452023/
关键词：
Low energy 3-nucleon system Nucleon-nucleon potential Analyzing power Scattering cross section Precise measurement Proton-deuteron scattering Capture gamma reaction Polarized neutron beam 三格子系二核子間力少数核子系 Feddeeu方程式 P波核力荷電対称性

项目摘要

The cross section, the vector and tensor analyzing powers of the p+d scattering below 18 MeV have been measured very accurately, and compared with the 3-body Faddeev calculation. The large (-25%) discrepancy between the experiment and the calculation at the maximum of Ay was not completely explained by the modification of the LS potential proposed by Takemiya. Besides, similarly large discrepancies were found also in the cross section and tensor analyzing powers. These facts indicate that the scalar, spin-vector and tensor components of the present nucleon-nucleon (NN) potentials need to be improved.After solving many experimental problems, the tensor analyzing powers of the d+p->^3He+gamma reaction at 17.5 MeV have been measured by 5-10 times more accurately than the previous data. The data showed apparent disagreement with the Faddeev calculation by Ishikawa-Sasakawa. Moreover, inclusion of the 3-nucleon force (3NF) enhanced the disagreement, contrary to the previous result at 29 MeV.The present data provided a severe constraint for the NN tensor force and the 3NF.To make a precise experiment on the n+d Ay, the intensity of the d beam was increased to 0.4 muA, and an n beam course was constructed at the Kyushu University tandem accelerator lab. Then test experiments were repeated on the production of the n beam, on the shielding of neutron and gamma-rays, and on the adjustment and the improvement of the detector systems. Moreover, it was confirmed that the n+d experiment could be made at RIKEN, using a high intensity d beam from the injector cyclotron. The experimental methods to measure the n beam polarization using n+^4He scattering within 1 % and to make accurate n+d Ay experiment have been established.

精确测量了18 MeV以下p+d散射的截面、矢量和张量分析功率，并与三体Faddeev计算进行了比较。实验结果与Ay最大值之间的较大偏差(-25%)不能完全用Taktemya提出的LS势修正来解释。此外，在横截面和张量分析功率上也发现了类似的较大差异。这些事实表明，目前核子-核子(NN)势的标量分量、自旋矢量分量和张量分量需要改进。在解决了许多实验问题后，测量了17.5 MeV下d+p-&gt；^3He+伽马反应的张量分析能力，比以前的数据精确了5-10倍。数据显示，与石川-佐佐川的Faddeev计算结果明显不一致。此外，包括3核子力(3Nf)加强了不一致，与先前在29 MeV下的结果相反。目前的数据对NN张量力和3Nf提供了严格的约束。为了对n+dAy进行精确的实验，d束的强度增加到0.4MUA，并在九州大学串列加速器实验室建立了n束课程。然后，在n束流的产生、中子和伽马射线的屏蔽以及探测器系统的调整和改进方面重复了测试实验。此外，还证实了n+d实验可以用来自注入回旋加速器的高强度d束在RIKEN上进行。建立了用1%以内的n+~4He散射测量n光束偏振度并进行精确的n+d Ay实验的实验方法。