论文标题
静态能量($ 2+1+1 $) - 风味晶格QCD:缩放设置和魅力效果
Static Energy in ($2+1+1$)-Flavor Lattice QCD: Scale Setting and Charm Effects
论文作者
论文摘要
我们在($ 2+1+1 $)中呈现静态能量的结果 - QCD在各种晶格间距上,以及包括物理夸克质量在内的几个夸克质量,以及MILC协作提供的晶格 - 岩石场配置的集合。我们获得了静态能量到近$ 1 $ 〜fm的结果,使我们能够同时确定量表$ r_ {1} $和$ r_ {0} $,以及字符串张力$σ$。对于最小的三个晶格间距,我们还确定了比例$ r_ {2} $。我们的$ r_ {0}/r_ {1} $和$ r_ {0} \sqrtσ$的结果与已发布的($ 2+1 $) - 风味结果一致。但是,我们对$ r_ {1}/r_ {2} $的结果与($ 2+1 $) - 风味盒中获得的值有很大不同,这很可能是由于魅力夸克的效果。我们还报告了$ r_ {0} $,$ r_ {1} $的结果,以及$ r_ {2} $ in〜fm,前者两个略低于发布($ 2+1 $) - 风味结果。我们通过比较我们对最佳两个格子的结果与先前发表的($ 2+1 $) - 风味QCD结果在类似的晶格间距上进行比较,详细研究了魅力夸克对静态能量的影响。我们发现,对于$ r> 0.2 $ 〜fm,我们在静态能源上的结果与($ 2+1 $) - 风味结果一致,这意味着这些距离的魅力夸克是脱钩的。另一方面,对于较小的距离,我们发现动态魅力夸克的效果很明显。晶格结果与构成有限符质量效应的静态能量的两环扰动表达非常吻合。这是第一次观察到魅力夸克的解耦,并在静态能的晶格数据上进行定量分析。
We present results for the static energy in ($2+1+1$)-flavor QCD over a wide range of lattice spacings and several quark masses, including the physical quark mass, with ensembles of lattice-gauge-field configurations made available by the MILC Collaboration. We obtain results for the static energy out to distances of nearly $1$~fm, allowing us to perform a simultaneous determination of the scales $r_{1}$ and $r_{0}$, as well as the string tension $σ$. For the smallest three lattice spacings we also determine the scale $r_{2}$. Our results for $r_{0}/r_{1}$ and $r_{0}\sqrtσ$ agree with published ($2+1$)-flavor results. However, our result for $r_{1}/r_{2}$ differs significantly from the value obtained in the ($2+1$)-flavor case, which is most likely due to the effect of the charm quark. We also report results for $r_{0}$, $r_{1}$, and $r_{2}$ in~fm, with the former two being slightly lower than published ($2+1$)-flavor results. We study in detail the effect of the charm quark on the static energy by comparing our results on the finest two lattices with the previously published ($2+1$)-flavor QCD results at similar lattice spacing. We find that for $r > 0.2$~fm our results on the static energy agree with the ($2+1$)-flavor result, implying the decoupling of the charm quark for these distances. For smaller distances, on the other hand, we find that the effect of the dynamical charm quark is noticeable. The lattice results agree well with the two-loop perturbative expression of the static energy incorporating finite charm mass effects. This is the first time that the decoupling of the charm quark is observed and quantitatively analyzed on lattice data of the static energy.