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

对18 MeV以下p+d散射的截面、矢量和张量分析能力进行了精确测量，并与三体Faddeev计算结果进行了比较。在Ay的最大值处，实验与计算之间的巨大差异（-25%）不能完全用Takemiya提出的LS势修正来解释。此外，在截面和张量分析能力上也发现了同样大的差异。这些事实表明，现有核子-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->^3He+ γ反应的张量分析能力，精度比以前提高了5-10倍。这些数据与石川-笹川的Faddeev计算结果存在明显的差异。此外，3核子力（3NF）的加入增强了这种分歧，这与先前在29 MeV下的结果相反。目前的数据为神经网络张量力和3NF提供了严格的约束。为了对n+d Ay进行精确实验，将d束强度提高到0.4 muA，并在九州大学串联加速器实验室建立了n束通道。然后对n束的产生、中子和伽马射线的屏蔽以及探测器系统的调整和改进进行了测试实验。此外，还证实了利用注入回旋加速器产生的高强度d束，可以在理研进行n+d实验。建立了用1%以内的n+^4He散射测量n束偏振的实验方法，并进行了精确的n+d Ay实验。

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.