论文标题
Lattice QCD的电动耦合的HADRONIC运行
The hadronic running of the electroweak couplings from lattice QCD
论文作者
论文摘要
电磁相互作用强度的能量依赖性（运行）$α$在标准模型的精确测试中起重要作用。前者对$ z $ pole的运行是全局电动型拟合的输入量，而混合角的运行易受超出标准模型物理的影响，尤其是在低能的情况下。我们介绍了在Lattice QCD的非扰动级别运行这些电动轴耦合的辐射真空极化（HVP）的计算，在类似$ q^2 $ tombimime的非扰动水平上，最高为$ q^2 $动量转移$ 7 \，\ mathrm {gev}^2 $。该数量也与HVP对MUON $ G-2 $的贡献密切相关。我们观察到$Δα^{（5）} _ {\ Mathrm {hast}}}（ - q^2）$的晶格结果之间的张力高达$ 3.5 $。然而，通过采用欧几里得分开技术和扰动QCD，将我们的结果转换为$ z $ pole时，这种张力会大大减轻，从而产生$δα^{（5）} _ {\ mathrm {hast}}}}（m_z^2）= 0.027 \ 0.027 \，73（15）$。该值与基于引用不确定性的$ r $ ratatio的结果一致，并且可以用作全球electroweak拟合后者的替代方案。
The energy dependency (running) of the strength of electromagnetic interactions $α$ plays an important role in precision tests of the Standard Model. The running of the former to the $Z$ pole is an input quantity for global electroweak fits, while the running of the mixing angle is susceptible to the effects of Beyond Standard Model physics, particularly at low energies. We present a computation of the hadronic vacuum polarization (HVP) contribution to the running of these electroweak couplings at the non-perturbative level in lattice QCD, in the space-like regime up to $Q^2$ momentum transfers of $7\,\mathrm{GeV}^2$. This quantity is also closely related to the HVP contribution to the muon $g-2$. We observe a tension of up to $3.5$ standard deviation between our lattice results for $Δα^{(5)}_{\mathrm{had}}(-Q^2)$ and estimates based on the $R$-ratio for $Q^2$ in the $3$ to $7\,\mathrm{GeV}^2$ range. The tension is, however, strongly diminished when translating our result to the $Z$ pole, by employing the Euclidean split technique and perturbative QCD, which yields $Δα^{(5)}_{\mathrm{had}}(M_Z^2)=0.027\,73(15)$. This value agrees with results based on the $R$-ratio within the quoted uncertainties, and can be used as an alternative to the latter in global electroweak fits.
