非微扰改进的对称保持框架下矢量介子和轴矢量介子的分布振幅
Distribution amplitudes of vector and axial-vector mesons in a nonperturbatively improved symmetry-preserving framework
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中文总结 AI 辅助
研究人员采用非微扰改进的对称保持施温格函数方法，重构矢量与轴矢量介子的分布振幅，发现轴矢量介子领域由对称性强制零点区分，二者味不对称大小并非关键。
中文摘要 AI 辅助
采用带有非微扰改进且保持对称性的核的连续施温格函数方法，我们对ρ、K*、a₁(1260)、b₁(1235)以及1⁺⁺和1⁺⁻轴矢量（AV）道的未混合奇异伙伴的领头扭度光前分布振幅（DAs）作出预测，这些预测是从相关的贝特-萨尔佩特波函数的梅林矩重构得到的。对于矢量介子，极化几乎不影响纵向动量份额：纵向和横向分布振幅几乎简并，且在二阶矩意义上均比渐近分布更窄。AV sector（轴矢量介子领域）则完全不同，电荷共轭要求一个投影（在1⁺⁺和1⁺⁻道之间互换）在x=1/2处消失并变号；SU_F(3)对称性破缺会消除这种保护，此时零阶矩变为非零，节点从中点移动。在共同加权归一化下，1⁺⁻道的零阶矩是1⁺⁺道的1.63倍，且轮廓畸变遵循相同模式。在对称极限下被电荷共轭禁止的耦合f_{b₁}=0，在奇异道中变为f_{K₁^{+-}}=0.019 GeV：这是从流矩阵元而非分布振幅重构得到的同一对称性破缺的独立测量结果。因此，区分两个领域的是对称性强制的零点，而非味不对称的大小。
英文摘要
Using continuum Schwinger-function methods with a nonperturbatively improved, symmetry-preserving kernel, we deliver predictions for the leading-twist light-front distribution amplitudes (DAs) of the $ρ$, $K^\ast$, $a_1(1260)$, $b_1(1235)$, and the unmixed strange partners of the $1^{++}$ and $1^{+-}$ axial-vector (AV) channels, reconstructed from Mellin moments of the associated Bethe--Salpeter wave functions. For vector mesons, polarisation barely affects longitudinal momentum sharing: the longitudinal and transverse DAs are nearly degenerate, and both narrower than the asymptotic distribution in the second-moment sense. The AV sector is different in kind. Charge conjugation compels one projection -- interchanged between the $1^{++}$ and $1^{+-}$ channels -- to vanish at $x=1/2$ and change sign; breaking $SU_F(3)$ symmetry removes this protection, whereupon the zeroth moments become nonzero and the nodes shift from the midpoint. Under a common weighted normalisation, the $1^{+-}$ zeroth moment is $1.63$ times that of the $1^{++}$ channel, and the profile distortion follows the same pattern. A coupling forbidden by charge conjugation in the symmetric limit, $f_{b_1}=0$, becomes $f_{K_1^{+-}}=0.019\,$GeV in the strange channel: an independent measure of the same symmetry breaking, obtained from a current matrix element rather than from the DA reconstruction. What distinguishes the two sectors is thus a symmetry-enforced zero, not the size of the flavour asymmetry.
发表机构
- Universidad de Huelva（韦尔瓦大学）
- Helmholtz-Zentrum Dresden-Rossendorf（德累斯顿-罗斯多夫亥姆霍兹中心）
- Anhui Normal University（安徽师范大学）
机构由 AI 辅助整理，请以论文原文为准。
