We present an update of our analysis of statistical and systematic errors in the calculation of iso-vector scalar, axial and tensor charges of the nucleon. The calculations are done using $N_f=2+1+1$ flavor HISQ ensembles generated by the MILC Collaboration at three values of the lattice spacing ($a=0.12,\ 0.09,$ and $0.06$ fm) and three values of the quark mass ($M_π\approx 310,\ 220$ and $130$ MeV); and clover fermions for calculating the correlation functions, i.e., we use a clover-on-HISQ lattice formulation. The all-mode-averaging method allows us to increase the statistics by a factor of eight for the same computational cost leading to a better understanding of and control over excited state contamination. Our current results, after extrapolation to the continuum limit and physical pion mass are $g_A^{u-d} = 1.21(3)$, $g_T^{u-d} = 1.005(59)$ and $g_S^{u-d} = 0.95(12) $. Further checks of control over all systematic errors, especially in $g_A^{u-d}$, are still being performed. Using results for the flavor-diagonal charges, $g_T^{u} $, $g_T^{d} $ and $g_T^{s}$, we analyze contributions of the quark electric dipole moment to the neutron EDM and the consequences for split SUSY model.
Nucleon Electric Dipole Moment from the $θ$ Term with Lattice Chiral Fermions
在晶格间距为0.11 fm的三种不同海π介子质量的畴壁晶格上，我们从带有重叠费米子的$θ$项计算了核子电偶极矩。由于重叠费米子的手征对称性守恒，我们定义了EDM的拓扑荷和手征极限。因此，手征外推可以在非零晶格间距可靠地进行。我们使用三到四个不同的部分猝灭价介子质量为每个海介子质量，发现EDM依赖于价和海介子质量表现相反，这可以描述的部分猝灭手征微扰理论。借助于集团分解误差约化（CDER）技术，我们确定了物理π质量下的中子和质子EDM分别为$d_{n}=-0.00148\left(14\right)\left(31\right)\barθ$ e $\cdot$ fm和$d_{p}=0.0038\left(11\right)\left(8\right)\barθ$ e $\cdot$ fm.这项工作是一个明确的示范的优势，使用手征费米子的核子EDM计算和铺平道路，未来的精确研究强$CP$违反的影响。
Neutron and proton electric dipole moments from $N_f=2+1$ domain-wall fermion lattice QCD
本文用$N_f=2+1$方法计算了中子和质子的电偶极矩。在QCD的$θ$真空中，中子和质子EDM形状因子是从次领先阶的三点函数中提取的。在这个计算中，我们使用介子质量0.33和0.42 GeV和2.7 fm $^3$晶格与岩崎规范作用和0.17 GeV的介子和4.6 fm $^3$晶格与I-DSDR规范作用，所有产生的RBC和UKQCD合作。全模式平均技术实现了高效和高统计计算。本文在重子手征微扰理论的基础上讨论了晶格EDM的手征行为。此外，我们还给出了三点和两点关联函数与局域拓扑分布关系的数值证据。
