S. Aoki, Y. Aoki, G. Cossu, H. Fukaya, S. Hashimoto, T. Kaneko, C. Rohrhofer, K. Suzuki
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引用次数: 16
Abstract
We investigate the axial U(1) anomaly of two-flavor QCD at temperatures 190--330 MeV. In order to preserve precise chiral symmetry on the lattice, we employ the Mobius domain-wall fermion action as well as overlap fermion action implemented with a stochastic reweighting technique. Compared to our previous studies, we reduce the lattice spacing to 0.07 fm, simulate larger multiple volumes to estimate finite size effect, and take more than four quark mass points, including one below physical point to investigate the chiral limit. We measure the topological susceptibility, axial U(1) susceptibility, and examine the degeneracy of U(1) partners in meson and baryon correlators. All the data above the critical temperature indicate that the axial U(1) violation is consistent with zero within statistical errors. The quark mass dependence suggests disappearance of the U(1) anomaly at a rate comparable to that of the SU(2)_L x SU(2)_R symmetry breaking.
我们研究了双味QCD在190—330 MeV温度下的轴向U(1)异常。为了保持晶格上精确的手性对称性,我们采用了莫比乌斯畴壁费米子作用以及用随机重加权技术实现的重叠费米子作用。与以往的研究相比,我们将晶格间距减小到0.07 fm,模拟更大的多体积来估计有限尺寸效应,并采用四个以上的夸克质量点,包括一个低于物理点的夸克质量点来研究手性极限。我们测量了拓扑磁化率,轴向U(1)磁化率,并检测了介子和重子相关子中U(1)伴子的简并性。在临界温度以上的所有数据表明,轴向U(1)违背在统计误差范围内与零一致。夸克质量依赖性表明,U(1)异常消失的速度与SU(2)_L x SU(2)_R对称性破缺的速度相当。