论文标题
在$ \ sqrt {s sqrt {s} = 13 $ tev的pp碰撞中，搜索顶级夸克和希格斯玻色子的风味的中性电流互动
Search for flavour-changing neutral current interactions of the top quark and the Higgs boson in events with a pair of $τ$-leptons in pp collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
论文作者
论文摘要
搜索涉及顶级夸克，另一个上的夸克（$ q = u $，$ c $）和标准型号（sm）higgs boson衰减，搜索涉及顶级夸克的中性电流（FCNC）$ TQH $交互作用，涉及$τ$ -Lepton Pair（$ HIGGS BOSON腐烂）该搜索基于$ \ sqrt {s} = 13 $ tev的$ pp $碰撞的数据集，该数据对应于139 fb $^{ - 1} $的集成光度，并记录在大型Hadron Collider的Atlas detector中。考虑了两个过程：与Higgs Boson（$ PP \ rightarrow th $）结合使用的单个顶级夸克FCNC生产，以及顶级夸克对生产，其中一对顶级夸克中的一个Quarks倒入$ WB $，而其他Quark Pair则通过FCNC Interactions通过FCNC Interactions倒入$ QH $。搜索选择两个强调衰减的$τ$ -Lepton候选人（$τ_ {\ text {hast}} $）或至少一个$τ_ {\ text {hast}} $带有额外的Lepton（$ e $，$ $），以及多个Jets。事件运动学用于通过多元判别剂将信号与背景区分开。观察到的数据略有过量，其显着性高于预期的SM背景2.3 $σ$，并且得出了$ t \与QH $分支比率的95％CL上限。 $ t \至ch $和$ t \至UH $分支比为$ 9.4 \ times 10^{ - 4} $ $（4.8^{+2.2} _ { - 1.4} _ { - 1.4} \ times 10^{ - 4}）$ 6.9 \ 6.9 \ times 10^^$ 4. $（3.5^{+1.5} _ { - 1.0} \ times 10^{ - 4}）$。在有效的$ TQH $耦合中，尺寸6操作员Wilson系数上的相应组合的（预期）上限为$ C_ {C {CCCccct} <1.35 $ $ $（0.97）$（0.97）$和$ C_ {ux {uxect} <1.16 $（0.82 $（0.82）$。
A search for flavour-changing neutral current (FCNC) $tqH$ interactions involving a top quark, another up-type quark ($q=u$, $c$), and a Standard Model (SM) Higgs boson decaying into a $τ$-lepton pair ($H\rightarrow τ^+τ^-$) is presented. The search is based on a dataset of $pp$ collisions at $\sqrt{s}=13$ TeV that corresponds to an integrated luminosity of 139 fb$^{-1}$ recorded with the ATLAS detector at the Large Hadron Collider. Two processes are considered: single top quark FCNC production in association with a Higgs boson ($pp\rightarrow tH$), and top quark pair production in which one of the top quarks decays into $Wb$ and the other decays into $qH$ through the FCNC interactions. The search selects events with two hadronically decaying $τ$-lepton candidates ($τ_{\text{had}}$) or at least one $τ_{\text{had}}$ with an additional lepton ($e$, $μ$), as well as multiple jets. Event kinematics is used to separate signal from the background through a multivariate discriminant. A slight excess of data is observed with a significance of 2.3$σ$ above the expected SM background, and 95% CL upper limits on the $t\to qH$ branching ratios are derived. The observed (expected) 95% CL upper limits set on the $t\to cH$ and $t\to uH$ branching ratios are $9.4 \times 10^{-4}$ $(4.8^{+2.2}_{-1.4}\times 10^{-4})$ and $6.9\times 10^{-4}$ $(3.5^{+1.5}_{-1.0}\times 10^{-4})$, respectively. The corresponding combined observed (expected) upper limits on the dimension-6 operator Wilson coefficients in the effective $tqH$ couplings are $C_{cϕ} <1.35$ $(0.97)$ and $C_{uϕ} <1.16$ $(0.82)$.
