发表机构
Nagoya University; Aichi University of Education（名古屋大学; 爱知教育大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
在适当时间正则化三味NJL模型中，计算K介子引力形状因子，对比其与π介子的结果，分析味对称性破缺对K介子力学结构的影响，明确C项投影约化对维持π介子低能定理的必要性。
AI 中文摘要
我们在适当时间正则化的三味Nambu--Jona-Lasinio（NJL）模型中研究K介子的引力形状因子（GFFs）。我们将K介子视为轻-奇异赝标量束缚态，利用修饰的夸克-引力子顶角计算其能量-动量张量矩阵元。通过保留相互作用诱导的接触项与夸克三角图，我们满足引力Ward-Takahashi恒等式，确保总能量-动量张量守恒。我们确定了轻夸克与奇异夸克对K介子GFFs的贡献，将其与对应的π介子结果对比，并提取相关的压强、剪切力分布以及Breit框架和横向光前质量半径。明确的味对称性破缺表明奇异部分携带K介子更大份额的动量与力学响应。因此，与π介子相比，K介子的D项负程度更小，力学分布更紧凑，具有增强的中心压强与剪切。我们进一步证明，在适当时间正则化中，保留Ward-Takahashi恒等式的C项投影约化对维持π介子低能定理至关重要。
英文摘要
We investigate the gravitational form factors (GFFs) of the kaon in a proper-time-regularized three-flavor Nambu--Jona-Lasinio model. We treat the kaon as a light--strange pseudoscalar bound state and evaluate its energy--momentum-tensor matrix element using a dressed quark--graviton vertex. By retaining the interaction-induced contact contribution alongside the quark triangle diagrams, we preserve the gravitational Ward--Takahashi identity and ensure the conservation of the total energy--momentum tensor. We determine the light- and strange-quark contributions to the kaon GFFs, contrast them with the corresponding pion results, and extract the associated pressure and shear-force distributions, together with the Breit-frame and transverse light-front mass radii. Explicit flavor-symmetry breaking dictates that the strange sector carries a larger share of the kaon momentum and mechanical response. Consequently, compared to the pion, the kaon exhibits a less negative $D$-term and more compact mechanical distributions, featuring enhanced central pressure and shear. We further show that a Ward--Takahashi-identity-preserving reduction of the $C$-term projection is essential for maintaining the pion low-energy theorem in proper-time regularization.
Comments14 pages, 4 figures
