论文标题
$τ$的普遍性和$ W $ -BOSON衰减的$τ$的通用性和$ t \ bar {t} $ evest
Test of the universality of $τ$ and $μ$ lepton couplings in $W$-boson decays from $t\bar{t}$ events with the ATLAS detector
论文作者
论文摘要
粒子物理的标准模型封装了我们当前对最小尺度物理学的最佳理解。该理论的基本公理是不同一代瘦素与电孔仪玻色子的耦合的通用性。 $ w $玻色子与$τ$ -Leptons and Muons的衰减率的比率，$ r（τ/μ）= b（w \ toτν_τ）/b（w \ w \ w \ w \μν_μ）$，构成了该套件的重要测试。使用Di-leptonic $ t \ bar {t} $事件对此数量进行测量，以139 fb $ {}^{ - 1} $进行的数据呈现，该数据的数据是proton--proton collisions in $ \ sqrt {s} = 13 $ tev的proton-- proton碰撞中录制的数据的数据。源自$ w $玻色子的muons和源自中间$τ$ -Lepton的muons使用$τ$ -Lepton的寿命，通过MUON Transverse撞击参数以及MUON Transversement Momentum Spectra的差异来区分。 $ r（τ/μ）$的值为$ 0.992 \ pm 0.013 [\ pm 0.007（stat）\ pm 0.011（syst）] $，并且与标准模型中假定的通用Lepton耦合的假设一致。这是该比率最精确的测量值，也是迄今为止大型强子对撞机的唯一测量。
The Standard Model of particle physics encapsulates our current best understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the electroweak gauge bosons. The measurement of the ratio of the rate of decay of $W$ bosons to $τ$-leptons and muons, $R(τ/μ) = B(W \to τν_τ)/B(W \to μν_μ)$, constitutes an important test of this axiom. A measurement of this quantity with a novel technique using di-leptonic $t\bar{t}$ events is presented based on 139 fb${}^{-1}$ of data recorded with the ATLAS detector in proton--proton collisions at $\sqrt{s}=13$ TeV. Muons originating from $W$ bosons and those originating from an intermediate $τ$-lepton are distinguished using the lifetime of the $τ$-lepton, through the muon transverse impact parameter, and differences in the muon transverse momentum spectra. The value of $R(τ/μ)$ is found to be $0.992 \pm 0.013 [\pm 0.007 (stat) \pm 0.011 (syst)]$ and is in agreement with the hypothesis of universal lepton couplings as postulated in the Standard Model. This is the most precise measurement of this ratio, and the only such measurement from the Large Hadron Collider, to date.
