论文标题
在QCD中以近临时到领先顺序的顶级宽度的分析结果
Analytic result for the top-quark width at next-to-next-to-leading order in QCD
论文作者
论文摘要
我们通过计算三环Quark自我能量图的想象中的想象部分，将近代到接头序列（NNLO）QCD校正的第一个完整分析结果（nnlo）QCD校正。结果均以谐波多组刻度表示，在整个区域中有效$ 0 \ le m_w^2 \ le m_t^2 $。 $ m_w^2 \至0 $和$ m_w^2 \至m_t^2 $限制的扩展与以前的研究相吻合。我们的结果也可以作为半衰减$ b \ t t t u $ $衰减的Lepton不变质量谱的确切预测。我们还通过分析计算衰减宽度，包括首次在QCD中的nnlo off-shell $ w $ boson效应。将这些贡献与Electroweak校正和有限$ B $ QUARK质量效应相结合，我们确定最精确的顶级宽度宽度为1.331 GEV，$ m_t = 172.69 $ GEV。对总理论不确定性，包括重新归一化量表选择，顶级重态化方案，输入参数和缺失的高阶校正的总理论不确定性进行了审查，并被仔细检查，并发现小于$ 1 \％$。
We present the first full analytic results of next-to-next-to-leading order (NNLO) QCD corrections to the top-quark decay width $Γ(t\to Wb)$ by calculating the imaginary part of three-loop top-quark self-energy diagrams. The results are all expressed in terms of harmonic polylogarithms and valid in the whole region $0\le m_W^2\le m_t^2$. The expansions in the $m_W^2\to 0$ and $m_W^2\to m_t^2$ limits coincide with previous studies. Our results can also be taken as the exact prediction for the lepton invariant mass spectrum in semileptonic $b\to u$ decays. We also analytically compute the decay width including the off-shell $W$ boson effect up to NNLO in QCD for the first time. Combining these contributions with electroweak corrections and the finite $b$-quark mass effect, we determine the most precise top-quark width to be 1.331 GeV for $m_t=172.69$ GeV. The total theoretical uncertainties including those from renormalization scale choice, top-quark renormalization scheme, input parameters, and missing higher-order corrections are scrutinized and found to be less than $1\%$.
