Study on internal hadron structure in RHIC-SPIN project

RHIC-SPIN项目内部强子结构研究

• 批准号: 12640260
• 负责人: KOIKE Yuji
• 金额: $ 1.86万
• 依托单位: NIIGATA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2000
• 资助国家: 日本
• 起止时间: 2000 至 2002
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-12640260/
• 关键词: RHIC-SPIN; Quantum Chromodynamics (QCD); Twist-3; Single spin asymmetry; Hyperon polarization; Quark gluon correlation; Sum rules; Semi-inclusive deep inelastic scattering; QCD; クォーク・グルーオン相関; セミインクルーシヴDIS; ダブルスピンアシンメトリー; シングルスピンアシメントリー; セミ・イン

I investigated the spin observables measured at RHIC-SPIN program based on Quantum Chromodynamics, in particular, the single spin asymmetry for the pion production from the collision of unpolarized proton and transversely polarized proton and the A hyperon polarization from unpolarized pp collisions. Both of these quantities are known as twist-3 observables which represent quark-gluon correlation in the hadrons not incorporated in the parton model picture. According to a QCD analysis, the single spin asymmetry receives three kinds of twist-3 cross sections depending on where the twist-3 functions comes from : (i) twist-3 polarized distribution (ii) twist-3 unpolarized distribution, and (iii) twist-3 fragmentation function. Likewise the hyperon polarization receives two kinds of twist-3 cross sections : (a) twist-3 unpolarized distribution from the initial proton and (b) twist-3 polarized fragmentation function for the final A. I have derived the cross section formula from these contrib … More utions systematically, and estimated the magnitude employing a moderate model assumptions for the unknown twist-3 functions. I also applied the same method to semi-inclusive production of pion and A from the deep inelastic lepton-nucleon scattering.Next 1 studied the twist-2 double spin asymmetries for the hadron production with large transverse momentum in semi-inclusive deep Inelastic scattering. I have derived the cross section formula for all the possible spin configurations in the semi-inclusive deep inelastic scattering e+p → e÷h+X where the final hadron h can be pion or A and two of e, p, h are polarized. I also estimated these spin asymmetries using the parton densities in the literature at COMPASS and EIC energies and discussed their characteristic features.The sum rules on the first moment of the twist-3 parton distributions h_L(x), e(x) and g_T(x) are reexamined. One-loop correction to these distributions was calculated for a massive quark target. We found a δ(x) contribution for h_L(x) and e(x) and thus the sum rule is not satisfied for these functions, while there is no such δ(x) contribution for g_T(x). We presented an argument that this results can be generalized -nonperturbatively. Less

研究了RHIC-SPIN程序中基于量子色动力学的自旋观测量，特别是非极化质子与横极化质子碰撞产生π介子的单自旋不对称性和非极化pp碰撞产生A超子的极化。这两个量都被称为twist-3观测量，它代表了强子中没有包含在部分子模型图像中的夸克-胶子关联。根据QCD分析，单自旋非对称性根据扭曲3函数的来源而具有三种扭曲3截面：（i）扭曲3极化分布，（ii）扭曲3非极化分布，（iii）扭曲3碎裂函数。同样地，超子极化也有两种扭曲3截面：（a）初始质子的扭曲3非极化分布和（B）末态质子的扭曲3极化碎裂函数。我从这些贡献中导出了截面公式。 ...更多信息 系统地，并估计的震级采用一个温和的模型假设为未知的扭曲-3功能。我也用同样的方法研究了从轻子-核子的深度非弹性散射中产生π介子和A介子的半包容性。其次，我研究了在半包容的深度非弹性散射中产生大横动量强子的扭转2双自旋不对称性。本文导出了半包容深度非弹性散射e+p → e_h+X中所有可能自旋组态的截面公式，其中末态强子h可以是π或A，e，p，h中的两个是极化的。我们还利用文献中的COMPASS和EIC能区的部分子密度估计了这些自旋不对称性，并讨论了它们的特征，重新考察了扭曲3部分子分布h_L（x），e（x）和g_T（x）的一阶矩的求和规则。单圈修正这些分布计算了一个大质量的夸克目标。我们发现了h_L（x）和e（x）的δ（x）贡献，因而这两个函数不满足求和规则，而g_T（x）没有δ（x）贡献。我们提出了一个论点，这个结果可以推广-非微扰。少

项目成果

小池 裕司: "Double spin asymmetries in large p_T hadron production in semi-inclusive DIS"Nuclear Physics B. (印刷中). (2003)

Yuji Koike：“半包容 DIS 中大型 p_T 强子产生中的双自旋不对称”《核物理 B》（出版中）。

M.Burkardt: "Violation of sum rules for twist-3 parton distributions in QCD"Nuclear Physics B. 632. 311-329 (2002)

M.Burkardt：“违反 QCD 中扭曲 3 部分子分布的求和规则”核物理 B. 632. 311-329 (2002)

小池裕司: "Quark cluster model and quark confinement"Progress of Theoretical Physics Supplement. 137. 21-42 (2000)

小池裕二：“夸克团簇模型和夸克禁闭”理论物理进展副刊137. 21-42 (2000)。

金澤 康信: "Polarization in hadronic Λ hyperon production and chiral-odd twist-3 distribution"Physical Review D. 64. 034019(1-5) (2001)

Yasunobu Kanazawa：“强子 Λ 超子产生中的极化和手性奇扭曲 3 分布”Physical Review D. 64. 034019(1-5) (2001)

Y. Koike, O. Morimatsu and K. Yazaki: "Quark cluster model and quark confinement"Progress of Theoretical Physics. 137. 21-41 (2000)

Y. Koike、O. Morimatsu 和 K. Yazaki：“夸克团簇模型和夸克禁闭”理论物理进展。