论文标题
搜索$ t \ bar th/a \ rightarrow t \ bar tt \ bar t $ t $生产在质子 - proton碰撞中的多leptton最终状态下的$ \ sqrt {s} = 13 $ tev带Atlas detector
Search for $t\bar tH/A \rightarrow t\bar tt\bar t$ production in the multilepton final state in proton-proton collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
论文作者
论文摘要
A search for a new heavy scalar or pseudo-scalar Higgs boson ($H/A$) produced in association with a pair of top quarks, with the Higgs boson decaying into a pair of top quarks ($H/A\rightarrow t\bar{t}$) is reported.搜索靶向最终状态，恰好有两个带有相同电荷或至少三个Leptons的钩子。分析的数据集对应于139 fb $^{ - 1} $的集成发光度，该质子 - 质子碰撞在LHC处的Atlas检测器，在13 tev的质量中心收集。两个多元分类器用于将信号与背景分开。没有观察到与标准模型期望相比，没有明显过多的事件。结果是在II型两-higgs-doublet模型的上下文中解释的。在$ t \ bar {t} h/a $生产横截面上，观察到的（预期）上限为95％的信心水平，$ h/a \ rightarrow t \ bar {t} $在14（10）fb和6（10）fb之间的分支率范围为400 GEV和400 GEV之间的重量。假设只有一个粒子，即标量$ h $或伪量表$ a $，则有助于$ t \ bar {t} t \ bar {t} $最终状态，$ \tanβ$的值低于1.2或0.5，分别以400 GEV或1000 GEV的质量排除在1.2或0.5中。当考虑两个颗粒时，这些排除范围将其增加到1.6或0.6 $ \tanβ$。
A search for a new heavy scalar or pseudo-scalar Higgs boson ($H/A$) produced in association with a pair of top quarks, with the Higgs boson decaying into a pair of top quarks ($H/A\rightarrow t\bar{t}$) is reported. The search targets a final state with exactly two leptons with same-sign electric charges or at least three leptons. The analysed dataset corresponds to an integrated luminosity of 139 fb$^{-1}$ of proton-proton collisions collected at a centre-of-mass energy of 13 TeV with the ATLAS detector at the LHC. Two multivariate classifiers are used to separate the signal from the background. No significant excess of events over the Standard Model expectation is observed. The results are interpreted in the context of a type-II two-Higgs-doublet model. The observed (expected) upper limits at 95% confidence level on the $t\bar{t}H/A$ production cross-section times the branching ratio of $H/A\rightarrow t\bar{t}$ range between 14 (10) fb and 6 (5) fb for a heavy Higgs boson with mass between 400 GeV and 1000 GeV, respectively. Assuming that only one particle, either the scalar $H$ or the pseudo-scalar $A$, contributes to the $t\bar{t}t\bar{t}$ final state, values of $\tanβ$ below 1.2 or 0.5 are excluded for a mass of 400 GeV or 1000 GeV, respectively. These exclusion ranges increase to $\tanβ$ below 1.6 or 0.6 when both particles are considered.
