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arXiv 2210.07597hep-phhep-lathep-th
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论量子色动力学(QCD)中的夸克谱函数

On the quark spectral function in QCD

Jan Horak, Jan M. Pawlowski, Nicolas Wink

AI总结:

本研究利用谱Dyson-Schwinger方程结合格点QCD胶子传播子的高斯过程回归结果,实时计算2+1味真空QCD的轻夸克谱函数,分析其解析结构与非物理极点条件,可用于输运及共振态性质的从头计算。

摘要:

我们在同位旋对称近似下,计算了2+1味真空量子色动力学(QCD)中轻味夸克的谱函数。我们采用谱Dyson-Schwinger方程,利用2+1味格点QCD胶子传播子数据的高斯过程回归最新谱重构结果,直接在实时域中计算非微扰夸克传播子。我们的结果显示,在大于传播子能隙标度的类时动量下存在类极点峰结构,以及负散射连续谱;我们在迭代求解过程中假设解析的极点-尾部分割来利用这一特性。计算还辅以关于夸克-胶子顶点与胶子传播子对夸克传播子解析结构影响的一般性讨论,我们特别探究了在何种条件下夸克传播子会出现非物理复极点。我们的结果具有广泛应用前景,涵盖QCD中输运性质以及共振态性质的从头计算。

英文摘要:

We calculate the spectral function of light quark flavours in 2+1 flavour vacuum QCD in the isospin-symmetric approximation. We employ spectral Dyson-Schwinger equations and compute the non-perturbative quark propagator directly in real-time, using recent spectral reconstruction results from Gaussian process regression of gluon propagator data in 2+1 flavour lattice QCD. Our results feature a pole-like peak structure at time-like momenta larger than the propagator's gapping scale as well as a negative scattering continuum, which we exploit assuming an analytic pole-tail split during the iterative solution. The computation is augmented with a general discussion of the impact of the quark-gluon vertex and the gluon propagator on the analytic structure of the quark propagator. In particular, we investigate under which conditions the quark propagator shows unphysical complex poles. Our results offer a wide range of applications, encompassing the ab-initio calculation of transport as well as resonance properties in QCD.

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