论文标题
从lattice qcd中的muon $（g-2）$中的光线散射的魅力夸克贡献
The charm-quark contribution to light-by-light scattering in the muon $(g-2)$ from lattice QCD
论文作者
论文摘要
我们使用lattice QCD计算了从符号夸克（Quark）对穆恩$ g-2 $的光线逐渐散射贡献。该计算是对用动态$（u，d，s）$ quarks生成的合奏（3）$ _ {\ rm f} $对称点，带有简并呈乳头和kaon质量为415 mev。它包括连接的魅力贡献，以及领先的断开灯芯收缩，涉及魅力与夸克环之间的相关性。事实证明，截止效果很大，这使我们使用比物理较轻的魅力质量使用较大的晶格间距，达到0.039 FM，并执行合并的魅力质量和连续的外推。我们使用$η_C$ Meson来定义物理魅力点，并获得$a_μ^{\ rm hlbl，c} =（2.8 \ pm 0.5）\ times 10^{ - 11} $的最终值，其不确定性由外推的系统占主导地位。我们的结果与基于简单的魅力循环的估计值一致，同时却没有对魅力质量的任何扰动方案依赖性。混合的魅力断开收缩的收缩对最终值的负数很小。
We compute the hadronic light-by-light scattering contribution to the muon $g-2$ from the charm quark using lattice QCD. The calculation is performed on ensembles generated with dynamical $(u,d,s)$ quarks at the SU(3)$_{\rm f}$ symmetric point with degenerate pion and kaon masses of around 415 MeV. It includes the connected charm contribution, as well as the leading disconnected Wick contraction, involving the correlation between a charm and a light-quark loop. Cutoff effects turn out to be sizeable, which leads us to use lighter-than-physical charm masses, to employ a broad range of lattice spacings reaching down to 0.039 fm and to perform a combined charm-mass and continuum extrapolation. We use the $η_c$ meson to define the physical charm-mass point and obtain a final value of $a_μ^{\rm HLbL,c} = (2.8\pm 0.5) \times 10^{-11}$, whose uncertainty is dominated by the systematics of the extrapolation. Our result is consistent with the estimate based on a simple charm-quark loop, whilst being free of any perturbative scheme dependence on the charm mass. The mixed charm-light disconnected contraction contributes a small negative amount to the final value.
