arXivDaily arXiv每日学术速递 周一至周五更新
arXiv周末暂无论文更新，休息一下吧，周末愉快~~
arXiv 2401.04049hep-lathep-ph
收藏

来自格点QCD的电磁耦合常数跑动中的强子贡献：短距离处的挑战

Hadronic contribution to the running of the electromagnetic coupling constant from lattice QCD: challenges at short distances

Sophie Mutzel

备注：
11 pages, 5 figures, contribution to the 39th International Symposium on Lattice Field Theory
阅读 PDF
arXiv 页面 ↗HTML 原文 ↗

AI总结：

本文研究格点QCD中电磁耦合常数跑动的强子贡献，针对高能区离散化误差与截断效应导致连续外推困难的问题，测试了基于格点微扰论的改进程序，并初步分析了$Q^2=5$ GeV$^2$处Adler函数的轻夸克连通贡献。

摘要：

电磁耦合常数$α$是标准模型（SM）的基本参数之一。其在Z玻色子质量处的值$α(M_Z)$备受关注，因为它进入电弱精度检验。当将$α$从低能跑动到Z质量时，精度损失了五个数量级。这使其成为该能标下SM中确定程度最差的参数之一。最大的误差源来自低能区的非微扰强子效应。这些非微扰效应可以通过格点QCD中的从头计算来确定。在需要与QCD微扰论匹配的更高能量处，离散化误差变大。此外，强子真空极化受到对数增强的截断效应影响，使得连续外推更加困难。为了更好地控制高能下的这种外推，我们测试了多种基于格点微扰论的改进程序。为了说明它们的效果，我们对欧几里得$Q^2=5$ GeV$^2$处Adler函数的轻夸克连通贡献进行了初步分析。格点结果是在夸克质量物理值处使用具有$2+1+1$味交错费米子的模拟获得的。

英文摘要：

The electromagnetic coupling constant, $α$, is one of the fundamental parameters of the Standard Model (SM). Its value at the Z boson mass, $α(M_Z)$, is of particular interest as it enters electroweak precision tests. When running $α$ from low energies up to the Z mass, five orders of magnitude in precision are lost. This makes it one of the least well determined parameters of the SM at that scale. The largest source of error comes from non-perturbative hadronic effects in the low energy region. These non-perturbative effects can be determined from ab-initio calculations in lattice QCD. At higher energies, needed to match onto QCD perturbation theory, discretization errors become large. In addition, the hadronic vacuum polarization receives logarithmically-enhanced cutoff effects which render the continuum extrapolation more difficult. To better control this extrapolation at higher energies, we test a number of improvement procedures based on lattice perturbation theory. To illustrate their effect, we present a preliminary analysis of the light quark, connected contribution to the Adler function at Euclidean $Q^2=5$ GeV$^2$. The lattice results are obtained using simulations with $2+1+1$ flavors of staggered fermions at physical values of the quark masses.

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。

↑