arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1906.01987hep-lat
收藏

格点上的分波分解及其在HAL QCD方法中的应用

Partial wave decomposition on the lattice and its applications to the HAL QCD method

Takaya Miyamoto, Yutaro Akahoshi, Sinya Aoki, Tatsumi Aoyama, Takumi Doi, Shinya Gongyo, Kenji Sasaki

摘要:

本文介绍了C。W. Misner的方法,在格点QCD中用HAL QCD方法计算了$S$波强子-强子散射。我们考虑了自旋单重态$Λ_c N$系统的Nambu-Bethe-Salpeter(NBS)波函数,在$(32a~\mathrm{fm})^3$格点上用$(2+1)$ -flavor QCD方法计算,格点间距为$a\simeq0.0907$ fm和$m_π\simeq 700$ MeV.我们发现,$l=0$组件可以成功地提取由Misner的方法从NBS波函数投影到$A_1^+$表示的立方群,其中包含小的$l\ge 4$组件。此外,虽然更高的分波分量被增强,从而产生显着的梳状结构,在传统的HAL QCD势,如果由通常的二阶差分近似的拉普拉斯算子被施加到NBS波函数,这样的结构被发现是不存在的潜在的Misner的方法提取,其中拉普拉斯算子可以解析地评估为每个分波分量。尽管在电位的差异,两种方法给出了几乎相同的结果的中心值和统计误差的大小的电位的拟合,从而对散射相移。这不仅表明用HAL QCD方法研究格点QCD时,Misner方法是有效的,而且表明即使用常规的HAL QCD方法,在研究$S$波散射时,高阶分波的干扰也得到了很好的控制。这将是有趣的研究在更高的分波通道中的相互作用的HAL QCD方法与Misner的分解,这种新技术的效用可能会变得更加清晰。

英文摘要:

The approximated partial wave decomposition method to the discrete data on a cubic lattice, developed by C. W. Misner, is applied to the calculation of $S$-wave hadron-hadron scatterings by the HAL QCD method in lattice QCD. We consider the Nambu-Bethe-Salpeter (NBS) wave function for the spin-singlet $Λ_c N$ system calculated in the $(2+1)$-flavor QCD on a $(32a~\mathrm{fm})^3$ lattice at the lattice spacing $a\simeq0.0907$ fm and $m_π\simeq 700$ MeV. We find that the $l=0$ component can be successfully extracted by Misner's method from the NBS wave function projected to $A_1^+$ representation of the cubic group, which contains small $l\ge 4$ components. Furthermore, while the higher partial wave components are enhanced so as to produce significant comb-like structures in the conventional HAL QCD potential if the Laplacian approximated by the usual second order difference is applied to the NBS wave function, such structures are found to be absent in the potential extracted by Misner's method, where the Laplacian can be evaluated analytically for each partial wave component. Despite the difference in the potentials, two methods give almost identical results on the central values and on the magnitude of statistical errors for the fits of the potentials, and consequently on the scattering phase shifts. This indicates not only that Misner's method works well in lattice QCD with the HAL QCD method but also that the contaminations from higher partial waves in the study of $S$-wave scatterings are well under control even in the conventional HAL QCD method. It will be of interest to study interactions in higher partial wave channels in the HAL QCD method with Misner's decomposition, where the utility of this new technique may become clearer.

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。

↑