一种用于重子奇偶性双重态结构的夸克 - 双夸克模型
A quark-diquark model for parity doublet structure of baryons
AI总结：
研究重子奇偶性双重态结构，提出其源于双夸克，构建三味手征夸克 - 双夸克模型，用最小参数集重现八重态重子谱等，手征对称性恢复后有独特倒质量层次，可提供手征对称性恢复的实验特征。
AI中文摘要：
重子的手征不变质量是奇偶性双重态模型的一个唯象输入，其微观起源仍是一个开放问题。我们提出手征不变质量和奇偶性双重态结构源于双夸克：标量（\(0^+\)）和赝标量（\(0^-\)）双夸克形成一个奇偶性双重态，其不变质量由胶子动力学产生而非夸克凝聚。我们构建了一个三味手征夸克 - 双夸克模型，其中夸克和双夸克通过一种从单胶子交换简化而来的手征不变四体相互作用束缚成重子。结果表明，夸克 - 双夸克结构自动产生了奇偶性双重态模型的两种手征表示和镜像分配，并且即使对于无质量夸克，复合重子也能获得手征不变质量。我们发现用一组最小参数就能很好地重现八重态重子谱和核子西格玛项。此外，在手征对称性恢复后，该模型预测了一种独特的倒质量层次：核子保持相对较重，而\(\Sigma\)和\(\Xi\)重子变得比核子轻。这种反质量排序因此可能为手征对称性恢复提供一种新的、可实验检验的特征。
英文摘要：
The chiral invariant mass of baryons is a phenomenological input of parity doublet models, and its microscopic origin remains an open question. We propose that the chiral invariant mass and the parity doublet structure originate from the diquarks: the scalar ($0^+$) and pseudoscalar ($0^-$) diquarks form a parity doublet whose invariant mass is generated by gluon dynamics rather than by the quark condensate. We construct a three-flavor chiral quark--diquark model in which a quark and a diquark are bounded into a baryon through a chiral-invariant four-body interaction whose structure is reduced from one-gluon exchange. It is shown that the quark--diquark structure automatically yields the two chiral representations and the mirror assignment of the parity doublet model, and the composite baryons acquire chiral invariant masses even for massless quarks. We find that the octet baryon spectrum and the nucleon sigma terms are reproduced very well with a minimal set of parameters. Furthermore, after chiral symmetry restoration, the model predicts a distinctive inverted mass hierarchy: the nucleon remains relatively heavy, whereas the $Σ$ and $Ξ$ baryon become lighter than the nucleon. This inverse mass ordering may therefore provide a novel, experimentally testable signature towards chiral symmetry restoration.
