The Investigation of the Nucleon Spin Structure and the Development of Polarized Targets

神经元自旋结构是高能物理学中最有趣和最重要的问题之一。在获得赠款援助（专门推广研究）的支持下，我们在五年内完成了三项研究。第一个主题是夸克和gluon自旋对核武器的贡献的研究。如果要清除夸克的作用，我们在1995年和1996年进行了SMC实验，并使用极化的双氢（二氢丁醇）和极化的质子（固体氨）目标。根据这些实验，夸克自旋对核自旋的贡献达到了20%-30%。Bjorken的总和规则是什么意思被认为是成功的测试了。这将保证OPE （操作员生产扩展）在QCD框架内的夸克-gluon问题的有效性方法。S-夸克的大小负自旋贡献再次被确认。基于这些合并，Gluon的旋转贡献已经成为一个重要的主题。我们现在的赠款援助已经刺激了t ... More 他的国际合作研究了gluon spin的作用，通过提出超导电磁铁的构造，为极化目标。The magnet has such？teristics as， （i） the maximum field strength of 2. 7 T with a homogeneity over 3 cm in diameter and 130 cm inlength， （ii） the dipole coil to produce 0. 6 T perpendicular to the solenoid field， （iii） the exit apture of ± 180 mrad。Magnet is now underconstruction and will be transported to CERN from ford Co. LTD soon。下一个贡献是scintillating fiber beam-tracker detectors which are mounted before and behind the polarized target的构造。这个追踪系统确定了在良好的时间和空间解决方案中出现和出现的粒子。scintillating fiber具有0.5 mm的直径。原型跟踪器为真正的muon光束提供了足够的时间分辨率（σ ~ 300 PS）。现在，实际实验的跟踪器的构造正在进行中，日本小组的另一个贡献是离线分析程序的构造。这个工作必须在真正的实验之前做好准备。两名日本成员为编写用于数据库、历史图显示和其他内容的程序作出了贡献。第二个主题是对GDH （Gerasimov， Drell-Hearn）和规则测试的研究。这一和规则涉及到极化光子-极化核反应交叉部分的异常磁性时刻。如果要执行这一和规则的测试，实验将被扩展到无限的能量。但是，总和规则包括因子1/ν （光子能量），更高能量部分的想法是不合理的。所以，一个人应该做一些有趣的实验。作为世界上的第一次实验，我们在1998年在美因茨进行了实验。数据在200-800 MeV的能量范围内收集。这些数据现在已经被分析了。为了实现高能量区域，我们准备在波恩大学的实验（最高可达2.5 GeV），在SPring-8（最高可达3 GeV）。第三个主题是极化目标的发展。在欧洲核研究组织开发了高极化和将精确极化价值转化为自旋-1系统的目标。在名古屋，我们试着将聚合物材料与聚乙烯醇相似。这些材料在房间温度下处理得很好。此帮助创建非常薄的目标材料。We polarized deuterated polyethylene （{CDイD22イエD2}n） which is prepared by two methods，i. e. free electron doping method and irradiation one by electron beam。我们确认了最高极化P= 16.7%的辐射D聚乙烯。Less（低）

The nulceon spin structure is one of the most interesting and important problems in high energy physics. By getting support of Grant-in-Aid(Specially Promoted Research), we performed three kinds of research in five years.The first subject is the research on the quark and gluon spin contributions to the nucleon one. In order to make clear the role of quarks, we performed SMC experiment in 1995 and 1996, using polarized deuteron (deuterated butanol) and polarized proton (solid ammonia) targets. By these experiments, the quark spin contribution to the nucleon spin has been determined as 20%〜30%. The Bjorken sum rule which is thought to beheld is successfully tested. This assured the validity of OPE (Operator Production Expansion) method to the quark-gluon problems in the frame of QCD. The sizable negative spin contribution by s-quark has been again confirmed. Based on those conclusions, the spin contribution of gluon has been an important subject. Our present Grant-in-Aid has stimulated t … More he international collaboration to investigate the role of gluon spin, by proposing the construction of the superconductive magnet, for the polarized target. The magnet has such characteristics as, (i) the maximum field strength of 2.7T with a homogeneity over 3cm in diameter and 130cm inlength, (ii) the dipole coil to produce 0.6T perpendicular to the solenoid field, (iii) the exit aperture of ± 180 mrad. The magnet is now underconstruction and will be transported to CERN from Oxford Co. LTD soon.The next contribution is the construction of the scintillating fiber beam-tracker detectors which are mounted before and behind the polarized target. This tracker system determined the incoming and outgoing muon in good time and space resolutions. The scintillating fiber has a diameter of 0.5mm. The prototype tracker gave enough time resolution (σ〜300 PS) for the real muon beam. Now, the construction of the tracker for the real experiment is going on.One more contribution of Japan group is the construction of the off-line analysis program. This job must be prepared before real experiments. Two Japanese members contribute to write programs for data base, histgram display and so on.Second subject is the research on the test of GDH (Gerasimov, Drell-Hearn) sum rule. This sum rule relates the anomalous magnetic moment to the polarized photon-polarized nucleon reaction cross section. To perform the test of this sum rule, the experiment has to be extended up to the infinite energy. But, the sum rule includes the factor 1/ν (ν : photon energy), the higher energy part is thought to be negligible. So, one should make experiment up to several GeV. As the first experiment in the world, we performed the experiment at Mainz in 1998. The data was taken in the energy range of 200-800 MeV. The data are now being analyzed. To achieve the higher energy region, we are preparing the experiments in Bonn Univ. (up to 2.5 GeV) and in SPring-8 (up to 3 GeV).Third subject is the development of the polarized target. The study at CERN developed the target for higher polarization, delivation of exact polarization value to spin-1 system. In Nagoya, we tried to polarize the polymer material like polyethylene. This material has a merit to be handled in room temperature. This helps to form very thin target material. We polarized deuterated polyethylene ({CDィイD22ィエD2}n) which is prepared by two methods, i.e. free electron doping method and irradiation one by electron beam. We confirmed the highest polarization P=16.7% to the irradiated d-polyethylene. Less