arXiv 1911.040642019-11hep-lathep-exhep-ph

用模型无关方法计算π介子电荷半径的格点量子色动力学

Lattice QCD calculation of the pion charge radius using a model-independent method

Xu Feng, Yang Fu, Lu-Chang Jin

备注：: 5 pages, 2 figures; v2, reference updated, we thank C. C. Chang for the useful information; v3, accepted for publication as PRD Rapid Communication
发表信息：: Phys. Rev. D 101, 051502 (2020)
DOI：: 10.1103/PhysRevD.101.051502

摘要：

我们使用一种方法来计算强子的电荷半径没有依赖模型的动量外推。该方法不需要在扭曲边界条件下进行额外的夸克传播子反演，也不需要计算夸克传播子的动量导数，因而易于实现。我们将此方法应用于π介子电荷半径$\langle r_π^2\rangle$的计算。为了进行比较，我们还用计算形状因子的斜率的传统方法来确定$\langle r_π^2\rangle$。新方法产生的结果与传统方法一致，统计误差小1.5-1.9倍。对于物理π质量下的四规范系综，采用$\lesssim50$组态，$\langle r_π^2\rangle$的统计误差在2.1%~ 4.6%之间。对于$m_π\approx 340$ MeV的系综，统计不确定性甚至降低到亚百分比水平。

英文摘要：

We use a method to calculate the hadron's charge radius without model-dependent momentum extrapolations. The method does not require the additional quark propagator inversions on the twisted boundary conditions or the computation of the momentum derivatives of quark propagators and thus is easy to implement. We apply this method to the calculation of pion charge radius $\langle r_π^2\rangle$. For comparison, we also determine $\langle r_π^2\rangle$ with the traditional approach of computing the slope of the form factors. The new method produces results consistent with those from the traditional method and with statistical errors 1.5-1.9 times smaller. For the four gauge ensembles at the physical pion masses, the statistical errors of $\langle r_π^2\rangle$ range from 2.1% to 4.6% by using $\lesssim50$ configurations. For the ensemble at $m_π\approx 340$ MeV, the statistical uncertainty is even reduced to a sub-percent level.

机构、总结、中文摘要均由AI分析而来，可能存在错误，请以论文正文为准。

摘要：

英文摘要：

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