格点量子色动力学中的π介子跃迁形状因子
Pion Transition Form Factor in Lattice QCD
AI总结：
该研究在格点量子色动力学中，采用混合方法与蒸馏框架，在$N_f=2+1$格点系综上计算π介子跃迁形状因子，确认连接与非连接贡献同号，非连接贡献约为连接部分的1%，实现概率振幅相长干涉。
AI中文摘要：
我们在格点量子色动力学中研究中性π介子跃迁形状因子$F_{\pi^0\gamma^\ast\gamma^\ast}(q_1^2,q_2^2)$，确认连接贡献与非连接贡献符号相同。采用新近提出的混合方法，该方法为所需的全对传播子提供无偏且廉价的估计量；外部π介子态通过蒸馏框架处理，电磁流在完整混合空间中计算。数值测试在$N_f=2+1$格点系综上开展，结果显示非连接部分贡献约为连接部分的1%，可实现概率振幅的相长干涉。
英文摘要：
We investigate the neutral pion transition form factor $F_{π^0γ^\astγ^\ast}(q_1^2,q_2^2)$ in lattice QCD and confirm that the connected and disconnected contributions have the same sign. We employ the recently proposed blending method, which supplies an unbiased and cheap estimators for the required all-to-all propagators. The external pion states are treated within the distillation framework, while the electromagnetic currents are evaluated in the full blending space. Numerical tests are performed on an $N_f=2+1$ lattice ensemble. Our result shows that the contribution of the disconnected part is approximately $1\%$ of that of the connected part and enables constructive interference of probability amplitudes.
