Measurement of the Spin-Dependent Structure Functions of the Neutron and Proton (Development of Polarized Deuteron and Proton Targets)

中子和质子自旋相关结构函数的测量（极化氘核和质子靶的开发）

• 批准号: 02044065
• 负责人: HORIKAWA Naoaki
• 金额: $ 17.28万
• 依托单位: Nagoya University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for international Scientific Research
• 财政年份: 1990
• 资助国家: 日本
• 起止时间: 1990 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-02044065/
• 关键词: Spin; Spin Dependent Structure Function; Polarized Deuteron Target; Spin Polarized Muon; NMR; スピン偏極ミュ-オン; 核子のスピン構造; 偏極標的; 核磁気共鳴; マイクロ波; 希釈冷却器

The motivation of the present research project is the previous EMC experiment which revealed the interesting of the quark spin inside nucleon. The experiment showed almost no contribution of the quark sipns to the nucleon spin. But, by out normal understanding based on the SU(3) or SU(6) madel, the sipn of the nucleon depends on those of quarks.Ellis-Jaffe had predicted the integral of the spin dependent structure function to the nucleon,taking the color SU(3) and no contribution of s-quark into consideration. By their prediction,the integral proton should give the value 0.189, but the experimental value 0.126. This discrepancy is fairly big. If one adopts the experimental value for the estimation of the whole sum of the quark spins inside the proton, it gives nearly. zero. After the publication of the EMC results, many discussions have been proposed, that is, (1) pointing out the ambiguity in experiment, (2) QCD break down, (3) looking for some other origins of the nucleon spin and so … More on. This topics is called " Spin Crisis".In order to settle the discussion and get the true view of the spin nucleon, it is necessary to accumulate more experimental data both for proton and neutron. Especially, the experiment for neutron is important, because the spinstructure function for the neutron has never been measured and there is a clear relation between proton and neutron called Bjorken sum rule based on the GCD. This relation called Bjorken sum rule can be checked the measurements for both proton and neutron. For the proton, more data with small errors and wide x region are requested.The present research project aims to make clear the puzzle of the nucleon spin which is one of the most exciting topics in high energy hadron physics. The experiment has been partly already achieved at CERN using 100 GeV polarized muon beam and polarized deuteron target.In This research program, two kinds of experiment for the experiment for the deuteron and proton targets are planned. Our Japanese group will contributes mainly to the praparation and development of the hugh polarized target. During the scattering experiment, we will have resposibility for the target operation. After the measurement, we will contribute the data analysis. Less

本研究项目的动机是以前的EMC实验，揭示了核子内夸克自旋的有趣性。实验表明夸克sipns对核子自旋几乎没有贡献。但是，根据SU（3）或SU（6）模型的一般理解，核子的自旋依赖性依赖于夸克的自旋依赖性，Ellis-Jaffe预言了自旋依赖性结构函数对核子的积分，考虑了色SU（3），而没有考虑s夸克的贡献。根据他们的预测，积分质子的值应该是0.189，而实验值是0.126。这个差距是相当大的。如果采用实验值来估计质子内部夸克自旋的总和，它几乎给出。零. EMC结果发表后，人们提出了许多讨论，如（1）指出实验中的不确定性，（2）QCD破裂，（3）寻找核子自旋的其他起源，等等。 ...更多信息 为了平息这场争论，获得自旋核子的真实面貌，需要积累更多的质子和中子的实验数据。特别是中子的实验是重要的，因为中子的自旋结构函数从未被测量过，并且质子和中子之间有一个明确的关系，称为基于GCD的Bjorken求和规则。这个关系称为比约肯求和规则，可以用质子和中子的测量来检验.对于质子，需要更多的误差小、x区域宽的数据，本研究计划的目的是解开核子自旋之谜，这是高能强子物理中最令人兴奋的课题之一。在欧洲核子研究中心（CERN），利用100 GeV的极化μ子束和极化氘靶已经完成了部分实验，本研究计划对氘靶和质子靶的实验进行两种方案的设计。我们日本小组将主要致力于高极化靶的研制。在散射实验中，我们将负责靶的操作。测量后，我们将进行数据分析。少

项目成果

B, Adeva et al. The Spin Muon Collaboration (SMC): "A High Precision Muon Beam Polarimeter Nucl. Instr. and Method"

B、阿德瓦等人。

N. Horikawa et al.: "Look for the origin of Nucleon Spin (Present Status of SMC Experiment)" Gensikaku-Kenkyuu (in Japanese). 37. 1-99 (1992)

N. Horikawa 等人：“寻找核子自旋的起源（SMC 实验的现状）”Gensikaku-Kenkyuu（日语）。

B. Adeva et al. The Spin Muon Collaboration (SMC): "Measurement of the Spin Structure Function g1(x) of the Deuteron" Physics Letters B.

B.阿德瓦等人。

A.Rijllart: "Instrumentation for the twoーlit椅re polarized tareget of the SMC Na47 experiment" Proc.of 9th Int.Syme.on High Energy Spin Physics To be published.

A.Rijllart：“SMC Na47 实验的两灯椅极化目标的仪器”Proc.of 9th Int.Syme.on High Energy Spin Psychos 即将出版。

B.Adeva.et al.(SMC): "A High Precision Muon Beam Polarimeter" Nucl.Instr.and Method.

B.Adeva.et al.(SMC)：“高精度 μ 子束旋光计”Nucl.Instr.and Method。