核子与π介子的引力D形状因子：双夸克态与四夸克态混合效应

中文摘要 AI 辅助

我们在一个扩展线性sigma模型（eLSM）中研究了核子与π介子的引力$D$形状因子，该模型同时包含双夸克态、四夸克态以及核子场。在标量介子主导的图像下，我们发现双夸克态与四夸克态之间的介子混合会抑制核子的$D$形状因子，并使其与格点QCD结果一致。有趣的是，先前在宇称双重态模型（PDM）中曾发现，核子质量中非零的手征不变分量会导致数量上相似的抑制效应。这表明，仅凭核子$D$形状因子难以区分介子混合与手征不变质量的影响。因此，我们进一步考察了手征极限下π介子的$D$形状因子。尽管在正向极限下其值在eLSM和PDM中均固定为$-1$，但介子混合会改变其对动量转移的依赖关系。相比之下，手征不变质量并不直接影响π介子的$D$形状因子。这些结果表明，对核子与π介子$D$形状因子的联合分析可以为核子质量分解和介子夸克组成提供更深入的见解。

英文摘要

We investigate the gravitational $D$-form factors of the nucleon and pion within an extended linear sigma model (eLSM) that incorporates both two-quark and four-quark states, as well as nucleon fields. Within the scalar-meson-dominance picture, we find that meson mixing between two-quark and four-quark states suppresses the nucleon $D$-form factor and leads to agreement with the lattice-QCD results. Interestingly, a quantitatively similar suppression was previously found in the parity doublet model (PDM) as a consequence of a nonzero chiral invariant component of the nucleon mass. This suggests that the effects of meson mixing and the chiral invariant mass are difficult to distinguish from the nucleon $D$-form factor alone. We therefore examine the pion $D$-form factor in the chiral limit. While its value in the forward limit remains fixed at $-1$ in both the eLSM and the PDM, meson mixing modifies its momentum-transfer dependence. In contrast, the chiral invariant mass does not directly affect the pion $D$-form factor. These results suggest that a combined analysis of the nucleon and pion $D$-form factors can provide further insight into the mass decomposition of the nucleon and the quark composition of mesons.

发表机构

• Center for Fundamental Physics, School of Mechanics and Photoelectric Physics, Anhui University of Science and Technology（安徽理工大学力学与光电物理学院基础物理中心）
• School of Frontier Sciences, Nanjing University（南京大学前沿科学学院）
• School of Physics, Nanjing University（南京大学物理学院）

机构由 AI 辅助整理，请以论文原文为准。

补充信息

备注

9 pages, 2 figures