arXiv 1302.22332013-02hep-lathep-phnucl-th

双味格点量子色动力学中的核子轴电荷和π介子衰变常数

Nucleon axial charge and pion decay constant from two-flavor lattice QCD

R. Horsley, Y. Nakamura, A. Nobile, P. E. L. Rakow, G. Schierholz, J. M. Zanotti

备注：: 16 pages, 8 figures; published version (Physics Letters B)
DOI：: 10.1016/j.physletb.2014.03.002

摘要：

在双味格点量子色动力学中计算了核子轴向电荷和π介子衰变常数。模拟进行了各种体积和晶格间距的晶格。结果报告的π介子质量低至$m_π=130\,\mbox{MeV}$。这两个量，$g_A$和$f_π$，受到大的有限尺寸效应，这对领导阶ChEFT和ChPT是相同的。通过考虑自然重整化比$g_A/f_π$，我们观察到一个普遍的行为作为减少夸克质量的函数。通过将比率外推到物理点，我们找到了$g_A^R=1.29(5)(3)$，使用$f_π$的物理值作为输入，使用$r_0=0.50(1)$设置比例。在随后的计算中，我们试图将$g_A$和$f_π$分别外推到无限体积。发现$g_A$和$f_π$的体积和夸克质量依赖性都被ChEFT和ChPT很好地描述。我们发现在物理点$g_A^R=1.24(4)$和$f_π^R=89.6(1.1)(1.8)\,\mbox{MeV}$。这两组结果与实验符合得很好。作为副产品，我们得到了低能常数$\bar{l}_4=4.2(1)$。

英文摘要：

The axial charge of the nucleon $g_A$ and the pion decay constant $f_π$ are computed in two-flavor lattice QCD. The simulations are carried out on lattices of various volumes and lattice spacings. Results are reported for pion masses as low as $m_π=130\,\mbox{MeV}$. Both quantities, $g_A$ and $f_π$, suffer from large finite size effects, which to leading order ChEFT and ChPT turn out to be identical. By considering the naturally renormalized ratio $g_A/f_π$, we observe a universal behavior as a function of decreasing quark mass. From extrapolating the ratio to the physical point, we find $g_A^R=1.29(5)(3)$, using the physical value of $f_π$ as input and $r_0=0.50(1)$ to set the scale. In a subsequent calculation we attempt to extrapolate $g_A$ and $f_π$ separately to the infinite volume. Both volume and quark mass dependencies of $g_A$ and $f_π$ are found to be well decribed by ChEFT and ChPT. We find at the physical point $g_A^R=1.24(4)$ and $f_π^R=89.6(1.1)(1.8)\,\mbox{MeV}$. Both sets of results are in good agreement with experiment. As a by-product we obtain the low-energy constant $\bar{l}_4=4.2(1)$.

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：

相关论文