Nucleon charges with dynamical overlap fermions
Nucleon charges with dynamical overlap fermions
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DOI：
10.1103/physrevd.98.054516
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发表时间：
2018-05
影响因子：
5
通讯作者：
N. Yamanaka;S. Hashimoto;T. Kaneko;H. Ohki
中科院分区：
文献类型：
--
作者：
N. Yamanaka;S. Hashimoto;T. Kaneko;H. Ohki
我们计算了$2+1$型格子QCD中核子的标量和张量电荷，其中断开图重整化的系统性得到了很好的控制。数值模拟以单个晶格间距 $a=0.11\text{ }\text{ }\mathrm{fm}$ 进行。我们模拟了四个π介子质量，其覆盖范围为${m}_{\ensuremath{\pi}}\ensuremath{\sim}290--540\text{ }\text{ }\mathrm{MeV}$，以及一个接近其物理值的奇怪夸克质量。通过采用所谓的低模式平均技术和截断求解器方法提高了统计精度。我们通过使用全夸克传播器计算断开图来研究上夸克、下夸克和奇异夸克对核子电荷的贡献。通过使用重叠夸克作用来精确保留手性对称性，以避免不同风格之间的算子混合，这使标量和张量矩阵元素的重整化变得复杂，并可能导致对小的奇异夸克贡献的严重污染。我们还利用断开图的贡献来研究核子轴向电荷。我们的结果与实验和之前的晶格研究相当一致。
We calculate the scalar and tensor charges of the nucleon in $2+1$-flavor lattice QCD, for which the systematics of the renormalization of the disconnected diagram is well controlled. Numerical simulations are performed at a single lattice spacing $a=0.11\text{ }\text{ }\mathrm{fm}$. We simulate four pion masses, which cover a range of ${m}_{\ensuremath{\pi}}\ensuremath{\sim}290--540\text{ }\text{ }\mathrm{MeV}$, and a single strange quark mass close to its physical value. The statistical accuracy is improved by employing the so-called low-mode averaging technique and the truncated solver method. We study up, down, and strange quark contributions to the nucleon charges by calculating disconnected diagrams using the all-to-all quark propagator. Chiral symmetry is exactly preserved by using the overlap quark action to avoid operator mixing among different flavors, which complicates the renormalization of scalar and tensor matrix elements and leads to possibly large contamination to the small strange quark contributions. We also study the nucleon axial charge with a contribution from the disconnected diagram. Our results are in reasonable agreement with experiments and previous lattice studies.