arXiv 1809.034872018-09-10hep-lat

格点量子色动力学对$θ$真空中核子矩阵元的改进

Improvements to Nucleon Matrix Elements within a $θ$ Vacuum from Lattice QCD

Jack Dragos, Thomas Luu, Andrea Shindler, Jordy de Vries, Ahmed Yousif

备注：: 7 pages, 12 figures, presented at the 36th International Symposium on Lattice Field Theory (Lattice 2018)

摘要：

利用梯度流计算了由QCD $θ$项引起的核子混合角$α_{N}$和核子电偶极矩EDM。为此，我们计算了拓扑荷，核子两点和三点关联函数。这些程序的目的是探讨如何拓扑电荷密度与核子插值算子相互作用。通过理解这种关系，我们可以尝试通过选择信号占主导地位的特定区域来抑制对$α_{N}$和EDM信号的噪声贡献。使用由PACS-CS在$N_{f}=2+1$提供的规范场，在固定的晶格间距$a=0.0907$ fm（$β=1.90$）、固定的尺寸$32^{3}\times 64$和变化的$m_π\approx\lbrace 411,\,570,\,701\rbrace$ MeV下选择第一集合的系综。在固定的$m_π\approx701$ MeV、固定的$L\approx1.9$ fm框大小和变化的$a=\lbrace 0.1215,\,0.0980,\,0.0685\rbrace $ fm下选择第二个集合。

英文摘要：

Using the gradient flow, we calculated the nucleon mixing angle $α_{N}$ and the nucleon electric dipole moment (EDM) induced by the QCD $θ$-term. To do so, we computed the topological charge, and the nucleon two-point and three-point correlation functions. The purpose of these proceedings is to explore how the topological charge density interacts with the nucleon interpolation operators. By understanding this relation, we can try to suppress noise contributions to the $α_{N}$ and EDM signals by selecting specific regions where the signal dominates. Using gauge fields provided by PACS-CS at $N_{f}=2+1$, a first collection of ensembles were selected at a fixed lattice spacing $a=0.0907$ fm ($β=1.90$), fixed dimensions $32^{3}\times 64$ and varying $m_π\approx\lbrace 411,\,570,\,701\rbrace$ MeV. A second collection was selected at fixed $m_π\approx701$ MeV, fixed box size of $L\approx1.9$ fm and varying $a=\lbrace 0.1215,\,0.0980,\,0.0685\rbrace $ fm.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

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