Topological susceptibility in two-flavor lattice QCD with exact chiral symmetry
Topological susceptibility in two-flavor lattice QCD with exact chiral symmetry
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DOI：
10.1016/j.physletb.2008.06.039
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发表时间：
2008-07-24
影响因子：
4.4
通讯作者：
Yamada, N.
中科院分区：
文献类型：
--
作者：
Aoki, S.;Chiu, T. W.;Yamada, N.
在固定的拓扑扇区上，我们利用晶格模拟确定了双味QCD中的拓扑磁化率X-t。拓扑电荷密度是明确地定义在晶格上使用具有精确的手征对称性的狄拉克算子。模拟在163 × 32的晶格上进行，晶格间距类似于0.12 fm，6个海夸克质量m（q），范围为m（s）/6 - m（s），其中m（s）为物理奇异夸克质量。Xt是从味单重态赝标介子两点函数在大距离下的时间关联的常数行为中提取出来的，这是由于固定拓扑的有限尺寸效应引起的。在小m（q）区域，我们的结果Xt与m（q）成比例，正如手征有效理论所预期的那样。利用Leutwyler-Smilga的公式X-t = m（q）Sigma/N-f，我们得到了N-f = 2 QCD中的手征凝聚为σ（MS）/bar（2GeV）= [252（5）（10）MeV]（3），与我们以前在c区得到的结果一致. (C)2008 Elsevier B. V.保留所有权利。
We determine the topological susceptibility X-t in two-flavor QCD using the lattice simulations at a fixed topological sector. The topological charge density is unambiguously defined on the lattice using the overlap-Dirac operator which possesses exact chiral symmetry. Simulations are performed on a 163 x 32 lattice at lattice spacing similar to 0.12 fm at six sea quark masses m(q) ranging in m(s)/6 - m(s) with m(s) the physical strange quark mass. The Xt is extracted from the constant behavior of the time-correlation of flavor-singlet pseudo-scalar meson two-point function at large distances, which arises from the finite size effect due to the fixed topology. In the Small m(q) regime, our result of Xt is proportional to m(q) as expected from chiral effective theory. Using the formula X-t = m(q) Sigma/N-f by Leutwyler-Smilga, we obtain the chiral condensate in N-f = 2 QCD as Sigma(MS) over bar (2 GeV) = [252(5)(10) MeV](3), in good agreement with our previous result obtained in the c-regime. (C) 2008 Elsevier B.V. All rights reserved.