Generalized parton distributions and tit nucleon spin structute

广义部分子分布和山核子自旋结构

• 批准号: 16540253
• 负责人: WAKAMATSU Masashi
• 金额: $ 2.25万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2004
• 资助国家: 日本
• 起止时间: 2004 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-16540253/
• 关键词: Nucleon spin structure; Nucleon spin puzzle; Generalized parton distributions; Chiral symmetry; Chiral soliton; bludemoul form factors; Nucleon anomalous maenetic moment; Deen inelastic scatterines; 核子の電磁形状因子; 核子の重力形状因子; 核子のスピン構造関数

The main purpose of the present project is to clarify the spin structure of the nucleon through the study of the generalized parton distributions (GPDs) functions based on the chiral quark soliton model. To evaluate GPDs, which depend on 3 kinematical variables, with full account of the nonperturbative polarization of the Dirac sea quarks is extremely difficult. As a first step, we therefore tried to evaluate the forward limit of the GPDs H and E, and also the corresponding generalized form factors, which are functions of 4-momentum transfer, defined as the x-moments of H and E. Although these quantities express only one profile of GPDs depending on 3 variables, they are shown to play crucial roles in disentangling the spin contents of the nucleon. In the process of this analyses, we noticed that we can make almost model-independent predictions on the nucleon spin contents and their scale dependence, solely relying upon the empirical information, and showed that the role of nucleon constituents as carriers of the nucleon spin are remarkably different below and above 1 GeV scale. To undertand this transition around 1GeV scale is extremely important for connecting the nonperturbative physics at low energy scale and the perturbative physics at high energy scale. Our predictions on the scale dependence of the nucleon spin contents will eventually be tested through precise measurements of GPDs. In parallel with this main research, we also carried out a comparative theoretical analysis of the transversities and the longitudinally polarized distribution functions and also performed a theoretical analysis of the NuTeV anomaly concerning the deviation of the Weinberg angle from the standard theory. We have also succedeed to give an analytical proof for the existence of delta-function type singularity in the chiral-odd twist-3 parton distribution e (x), and could connect its origin to nontrivial structure of the QCD vacuum.

本项目的主要目的是通过研究基于手征夸克孤子模型的广义部分子分布(GPD)函数来阐明核子的自旋结构。要在充分考虑狄拉克海夸克的非微扰极化的情况下，计算依赖于3个运动学变量的GPD是极其困难的。因此，作为第一步，我们试图评估GPDS H和E的前进极限，以及相应的广义形式因子，它们是定义为H和E的x-矩的4动量转移的函数。尽管这些量仅表示依赖于3个变量的GPD的一个轮廓，但它们被证明在解开核子的自旋含量方面起着关键作用。在这一分析过程中，我们注意到，仅依靠经验信息，我们就可以对核子自旋含量及其尺度依赖做出几乎独立于模型的预测，并表明在1GeV尺度以下和1GeV以上，核子组分作为核子自旋载体的作用是显著不同的。理解这种在1GeV尺度附近的跃迁对于连接低能尺度的非微扰物理和高能尺度的微扰物理是极其重要的。我们对核子自旋含量的尺度依赖关系的预测最终将通过对GPD的精确测量来检验。在这一主要研究的同时，我们还对横向分布函数和纵向极化分布函数进行了比较理论分析，并对NuTeV异常的Weinberg角偏离标准理论进行了理论分析。我们还成功地给出了手征奇扭3部分子分布e(X)中存在Delta函数型奇异性的解析证明，并将其起源与QCD真空的非平凡结构联系起来。

项目成果

Generalized form factors, generalized parton distributions and the spin contents of the nucleon

核子的广义形状因子、广义部分子分布和自旋内容

• 发表时间: 2006
• 期刊: Physical Review D 74
• 作者: M.Fukunaga;T.Onogi;若松正志;若松 正志
• 通讯作者: 若松 正志

GDPs and underlying spin structure of the nucleon

GDP 和核子的基础自旋结构

• 发表时间: 2006
• 期刊: in Proceedings of Advanced Studies Institute on Symmetries and Spin (2005), Prague (印刷中)
• 作者: H.Fukaya;T.Onogi;S.Hashimoto;T.Hirohashi;K.Ogawa;若松正志
• 通讯作者: 若松正志

Generalized parton distribution functions and the nucleon spin sum rule in the chiral quark soliton model

手性夸克孤子模型中的广义部分子分布函数与核子自旋和规则

• 发表时间: 2005
• 期刊: Physical Review D 71
• 作者: S.Hashimoto;T.Onogi;若松 正志
• 通讯作者: 若松 正志

Comparative analysis of the transversities and longitudinally polarized distribution functios of the nucleon

核子横向和纵向极化分布函数的比较分析

• 发表时间: 2007
• 作者: M.;Wakamatsu;若松 正志
• 通讯作者: 若松 正志

Chiral-odd twist-3 e(x) of the nucleon

核子的手性奇扭曲 3 e(x)

• 发表时间: 2005
• 期刊: Nuclear Physics A 755
• 作者: Y.;Ohnisbi
• 通讯作者: Ohnisbi