Determination of the quark condensate from heavy-light current-current correlators in full lattice QCD
Determination of the quark condensate from heavy-light current-current correlators in full lattice QCD
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DOI：
10.1103/physrevd.100.034506
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发表时间：
2018-11
影响因子：
5
通讯作者：
C. Davies;K. Hornbostel;J. Komijani;J. Koponen;G. Lepage;A. Lytle;C. McNeile
中科院分区：
文献类型：
--
作者：
C. Davies;K. Hornbostel;J. Komijani;J. Koponen;G. Lepage;A. Lytle;C. McNeile
我们导出了算符乘积展开式，其真空期望值给出了赝标重-轻流-流相关器的时间矩，直到并包括$\alpha_s ^2 $乘以$\langle\overline{\psi}\psi\rangle/M^3$中的项和$\alpha_s$乘以$\langle \alpha_s G^2 \rangle/M^4$中的项，其中$M$是重夸克质量。利用在胶子场组态上的各种重夸克质量的格点QCD结果，包括海中的u夸克、d夸克和s夸克在三种格点间距下的重奇异凝聚，我们能够表明奇异凝聚对时间矩的贡献是非常大的.我们使用我们的格点QCD时间矩和OPE来确定凝聚体的值，同时拟合第4，第6，第8和第10时间矩。我们的结果，$\langle \overline{s}s \rangle^{\overline{MS}}（2 \text{GeV}）= -（296（11）\，\mathrm{MeV}）^3 $，与HPQCD早期更直接的格点QCD测定结果一致。除了证实s夸克凝聚与轻夸克凝聚的数值接近外，这也清楚地表明了格点QCD中短程算符矩阵元的完全非微扰计算的算符乘积展开式的一致性。
We derive the Operator Product Expansion whose vacuum expectation value gives the time-moments of the pseudoscalar heavy-light current-current correlator up to and including terms in $\alpha_s^2$ multiplying $\langle\overline{\psi}\psi\rangle/M^3$ and terms in $\alpha_s$ multiplying $\langle \alpha_s G^2 \rangle/M^4$, where $M$ is the heavy-quark mass. Using lattice QCD results for heavy-strange correlators obtained for a variety of heavy quark masses on gluon field configurations including $u$, $d$ and $s$ quarks in the sea at three values of the lattice spacing, we are able to show that the contribution of the strange-quark condensate to the time-moments is very substantial. We use our lattice QCD time-moments and the OPE to determine a value for the condensate, fitting the 4th, 6th, 8th and 10th time-moments simultaneously. Our result, $\langle \overline{s}s \rangle^{\overline{\text{MS}}}(2 \text{GeV}) = -(296(11) \,\mathrm{MeV})^3$, agrees well with HPQCD's earlier, more direct, lattice QCD determination~\cite{McNeile:2012xh}. As well as confirming that the $s$ quark condensate is close in value to the light quark condensate, this demonstrates clearly the consistency of the Operator Product Expansion for fully nonperturbative calculations of matrix elements of short-distance operators in lattice QCD.