标题： 使用2+1味格点QCD的精确核子电荷和形式因子 显示英文标题

标题： Precision Nucleon Charges and Form Factors Using 2+1-flavor Lattice QCD

摘要： 我们使用七组2+1味Wilson-clover费米子进行了对同位旋矢量核子电荷和形式因子的高统计研究。 在关联函数的谱分解中包含较低能量的$N \pi$激发态后得到的轴矢量和赝标量形式因子满足它们之间的部分守恒轴矢流关系。 同样，我们发现证据表明$N\pi \pi $激发态通过矢量电流的插入对关联函数有贡献，这与矢量介子主导模型一致。 所得的形式因子与实验电和磁数据的Kelly参数化一致。 我们对同位旋矢量电荷的最终估计值为$g_{A}^{u-d} = 1.31(06)(02)_{\rm FV}(02)_Z (04)_{\rm ES}$、$g_{S}^{u-d} = 1.06(10)(02)_Z (06)_{\rm a}$和$g_{T}^{u-d} = 0.95(05)(01)_Z (01)_{\rm ES}$。 形式因子给出：(i) 轴电荷半径平方，${\langle r_A^2 \rangle}^{u-d}=0.428(53)(30) \ {\rm fm}^2$，(ii) 诱导的赝标电荷，$g_P^\ast=7.9(7)(9)$，(iii) 介子-核子耦合，$g_{\pi {\rm NN}} = 12.4(1.2)$，(iv) 电荷半径平方，${\langle r_E^2 \rangle}^{u-d} = 0.85(12)(19) \ {\rm fm}^2$，(v) 磁电荷半径平方，${\langle r_M^2 \rangle}^{u-d} = 0.71(19)(23) \ {\rm fm}^2$，和(vi) 磁矩，$\mu^{u-d} = 4.15(22)(10)$。 这些结果都与现象学/实验结果一致。 最后，我们提出了轴矢、电和磁形式因子在范围$0.04 < Q^2 < 1$ GeV${}^2$的简单Padé参数化，用于现象学研究。 显示英文摘要

摘要： We present a high statistics study of the isovector nucleon charges and form factors using seven ensembles of 2+1-flavor Wilson-clover fermions. The axial vector and pseudoscalar form factors obtained on including the lower energy $N \pi$ excited state in the spectral decomposition of correlation functions satisfy the partially conserved axial current relation between them. Similarly, we find evidence that the $N\pi \pi $ excited state contributes to the correlation functions with the insertion of the vector current, consistent with the vector meson dominance model. The resulting form factors are consistent with the Kelly parameterization of the experimental electric and magnetic data. Our final estimates for the isovector charges are $g_{A}^{u-d} = 1.31(06)(02)_{\rm FV}(02)_Z (04)_{\rm ES}$, $g_{S}^{u-d} = 1.06(10)(02)_Z (06)_{\rm a}$, and $g_{T}^{u-d} = 0.95(05)(01)_Z (01)_{\rm ES}$. The form factors yield: (i) the axial charge radius squared, ${\langle r_A^2 \rangle}^{u-d}=0.428(53)(30) \ {\rm fm}^2$, (ii) the induced pseudoscalar charge, $g_P^\ast=7.9(7)(9)$, (iii) the pion-nucleon coupling $g_{\pi {\rm NN}} = 12.4(1.2)$, (iv) the electric charge radius squared, ${\langle r_E^2 \rangle}^{u-d} = 0.85(12)(19) \ {\rm fm}^2$, (v) the magnetic charge radius squared, ${\langle r_M^2 \rangle}^{u-d} = 0.71(19)(23) \ {\rm fm}^2$, and (vi) the magnetic moment $\mu^{u-d} = 4.15(22)(10)$. These are all consistent with phenomenological/experimental results. Lastly, we present a simple Pad\'e parameterization of the axial, electric and magnetic form factors over the range $0.04 < Q^2 < 1$ GeV${}^2$ for phenomenological studies.