AI 中文总结
该研究针对低能QCD，采用闵可夫斯基空间的谱函数重整化群与扩展的涌现复合方法，计算含全阶散射衰变的夸克和介子谱函数，揭示高阶散射对π介子过程的重要性。
AI 中文摘要
我们计算低能量子色动力学（QCD）中的夸克与介子谱函数，包含π介子、标量σ模式的全阶散射与衰变过程。低能时胶子退耦，两味QCD的动力学可由夸克-介子模型很好描述。计算直接在闵可夫斯基空间中开展，采用谱函数重整化群方法。通过扩展至实时过程的涌现复合方法，可完整捕捉介子的实时动力学。通过对散射尾的自洽处理，以及利用贝塞耳-萨尔佩特方程对四介子顶角进行依赖动量的重求和，实现了全阶散射与衰变的包含。我们以π→3π散射阈值为例说明高阶散射的重要性，该过程是π介子运动学上最低的可及道。
英文摘要
We compute quark and meson spectral functions in low-energy QCD, including all-order scatterings and decays of pions and the scalar $σ$-mode. For low energies the gluons decouple and the dynamics of two-flavour QCD is well-described by a Quark-Meson model. The computations are performed directly in Minkowski space, using the spectral functional renormalisation group. The full mesonic realtime dynamics is captured with the emergent composite approach which is extended here to realtime processes. The inclusion of all-order scatterings and decays is achieved through the self-consistent treatment of the scattering tails and the momentum-dependent resummation of the four-meson vertex via its Bethe-Salpeter equation. We illustrate the importance of higher-order scatterings using the example of the $π\to 3π$ scattering threshold - the lowest kinematically accessible channel for the pion.
Comments27 pages, 16 figures, 1 table
