VMD模型中强子真空极化内的电磁同位旋破缺
Electromagnetic isospin breaking in hadronic vacuum polarization within a VMD model
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中文总结 AI 辅助
该研究针对格点QCD计算缪子(g-2)μ时的电磁同位旋破缺修正难题，采用VMD模型唯象估算相关Wick收缩的大小，给出π介子贡献及哑铃收缩的关键结果，为无限体积基准提供支撑。
中文摘要 AI 辅助
现代格点QCD计算缪子(g-2)μ的领头强子真空极化贡献时，极具挑战性的部分之一是电磁导致的同位旋破缺修正。该修正以长程为主，存在严重的信噪比问题和有限体积效应。为给各类夸克层面Wick收缩提供无限体积基准，我们采用先前开发的矢量介子主导（VMD）模型，在物理点上唯象估算其大小。该模型中π介子贡献总和约为-7.1×10^-10，由电磁π介子质量移动主导；紫外有限的(2+2)a（“哑铃”）收缩约占该模型总和的三分之二，两者中约30%来自大于2.8 fm的欧几里得时间。
英文摘要
One of the challenging components of modern lattice-QCD computations of the leading hadronic vacuum polarization contribution to the muon $(g-2)_μ$ is the isospin-breaking correction due to electromagnetism. Dominated by long distances, this correction suffers from severe signal-to-noise issues and finite-volume effects. To provide infinite-volume benchmarks for various quark-level Wick contractions, we estimate their sizes phenomenologically at the physical point, using a previously developed vector-meson-dominance model. The pion contributions in this model sum to around $-7.1\times 10^{-10}$, dominated by the electromagnetic pion mass shift. The ultraviolet-finite (2+2)a ("dumbbell") contraction accounts for approximately two thirds of this model sum; for both, about 30% comes from Euclidean times beyond 2.8 fm.
发表机构
- Aix-Marseille Université, Université de Toulon, CNRS, CPT（艾克斯-马赛大学、土伦大学、法国国家科学研究中心、CPT）
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