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arXiv 0907.2269hep-ph
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核子的夸克结构与质子-中子硬弹性散射的角不对称性

Quark Structure of the Nucleon and Angular Asymmetry of Proton-Neutron Hard Elastic Scattering

Carlos G. Granados, Misak M. Sargsian

摘要:

本文研究了质子-中子硬弹性散射角分布相对于90度质心散射角的不对称性。我们证明了角不对称性的大小与核子的夸克波函数的螺旋-同位旋对称性有关。我们对硬散射的夸克交换模型中的不对称性的估计表明,基于精确SU(6)对称性的核子的夸克波函数预测了与实验观测相反的角不对称性。另一方面,基于核子双夸克图像的夸克波函数产生了与数据一致的不对称性。通过与实验数据的比较,我们得到了核子夸克波函数中双夸克矢量和标量分量的相对符号和大小。这两个量在约束核子的QCD模型中是必不可少的。总的来说,我们的结论是重子硬弹性散射的角不对称性为研究重子的夸克胶子结构提供了一个新的途径,应该被看作是约束理论模型的一个重要观测量。

英文摘要:

We investigate an asymmetry in the angular distribution of hard elastic proton-neutron scattering with respect to 90deg center of mass scattering angle. We demonstrate that the magnitude of the angular asymmetry is related to the helicity-isospin symmetry of the quark wave function of the nucleon. Our estimate of the asymmetry within the quark-interchange model of hard scattering demonstrates that the quark wave function of a nucleon based on the exact SU(6) symmetry predicts an angular asymmetry opposite to that of experimental observations. On the other hand the quark wave function based on the diquark picture of the nucleon produces an asymmetry consistent with the data. Comparison with the data allowed us to extract the relative sign and the magnitude of the vector and scalar diquark components of the quark wave function of the nucleon. These two quantities are essential in constraining QCD models of a nucleon. Overall, our conclusion is that the angular asymmetry of a hard elastic scattering of baryons provides a new venue in probing quark-gluon structure of baryons and should be considered as an important observable in constraining the theoretical models.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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