论文标题
电磁耦合和电子混合角的望态运行
The hadronic running of the electromagnetic coupling and electroweak mixing angle
论文作者
论文摘要
我们介绍了电磁耦合的HADRONIC运行和从$ n_f = 2+1 $ o（a）$（A）$改进的Wilson Fermions的lattice QCD模拟的弱混合角。使用矢量电流的两个不同的离散化，我们计算了对HADRONIC真空极化（HVP）函数$ \barπ^{γγγ} $和$ \ \barπ^{Zγ} $ spacelike Moments Moments $ q^2 \ $ $ $ $ $ \ c的$ \barπ^{Zγ} $ {我们的结果在四个晶格间距处使用合奏将其推断到物理点，pion质量为130至420 meV。我们观察到我们的晶格结果之间最多3.5个标准偏差的张力，价格为$Δα_ {\ rm at}^{（5）}（ - q^2）$和基于$ \ textIt {r textit {r} $ - 在范围$ q^2 = 3-7 \ \ rm gev的范围的space-like momenta的估计值。要获得$Δα_\ Mathrm {have}^{（5）}（m_z^2）$的估计，我们采用了Euclidean拆分技术。评估了与全球电动拟合的比较的含义。
We present results for the hadronic running of the electromagnetic coupling and the weak mixing angle from simulations of lattice QCD with $N_f=2+1$ flavours of $O(a)$-improved Wilson fermions. Using two different discretisations of the vector current, we compute the quark-connected and -disconnected contributions to the hadronic vacuum polarisation (HVP) functions $\barΠ^{γγ}$ and $\barΠ^{Zγ}$ for spacelike squared momenta $Q^2\leq 7$ $\mathrm{GeV}^2$. Our results are extrapolated to the physical point using ensembles at four lattice spacings, with pion masses ranging from 130 to 420 MeV. We observe a tension of up to 3.5 standard deviations between our lattice results for $Δα_{\rm had}^{(5)}(-Q^2)$ and estimates based on the $\textit{R}$-ratio for space-like momenta in the range $Q^2=3-7\,\rm GeV^2$. To obtain an estimate for $Δα_\mathrm{had}^{(5)}(M_Z^2)$, we employ the Euclidean split technique. The implications for comparison with global electroweak fits are assessed.
