"Table 19" of "Search for heavy particles decaying into a top-quark pair in the fully hadronic final state in $pp$ collisions at $\sqrt{s} =13$ TeV with the ATLAS detector"

A search for new particles decaying into a pair of top quarks is performed using proton-proton collision data recorded with the ATLAS detector at the Large Hadron Collider at a center-of-mass energy of $\sqrt{s}$ = 13 TeV corresponding to an integrated luminosity of 36.1 fb$^{-1}$. Events consistent with top-quark pair production and the fully hadronic decay mode of the top quarks are selected by requiring multiple high transverse momentum jets including those containing b-hadrons. Two analysis techniques, exploiting dedicated top-quark pair reconstruction in different kinematic regimes, are used to optimize the search sensitivity to new hypothetical particles over a wide mass range. The invariant mass distribution of the two reconstructed top-quark candidates is examined for resonant production of new particles with various spins and decay widths. No significant deviation from the Standard Model prediction is observed and limits are set on the production cross-section times branching fraction for new hypothetical $Z^{\prime}$ bosons, dark-matter mediators, Kaluza-Klein gravitons and Kaluza-Klein gluons. By comparing with the predicted production cross-sections, the $Z^{\prime}$ boson in the topcolor-assisted-technicolor model is excluded for masses up to 3.1−3.6 TeV, the dark-matter mediators in a simplified framework are excluded in the mass ranges from 0.8 TeV to 0.9 TeV and from 2.0 TeV to 2.2 TeV, and the Kaluza-Klein gluon is excluded for masses up to 3.4 TeV, depending on the decay widths of the particles.

本研究利用大型强子对撞机（Large Hadron Collider）上ATLAS探测器（ATLAS detector）采集的、质心系能量√s=13 TeV且积分亮度为36.1 fb⁻¹的质子-质子碰撞数据，开展了针对衰变至顶夸克对的新粒子的搜寻工作。通过筛选包含多个带有b强子的高横向动量喷注，我们选取了与顶夸克对产生及顶夸克全强子衰变模式相符的事例。本分析采用两种分析技术，分别在不同运动学区域内对顶夸克对进行专属重建，以优化对宽质量范围中新假想粒子的搜寻灵敏度。针对具有不同自旋与衰变宽度的新粒子的共振产生过程，我们对两个重建顶夸克候选体的不变质量分布进行了检验。结果未观测到与标准模型（Standard Model）预言存在显著偏离的信号，因此对新假想Z'玻色子（Z' boson）、暗物质传递者（dark-matter mediators）、卡鲁扎-克莱因引力子（Kaluza-Klein gravitons）及卡鲁扎-克莱因胶子（Kaluza-Klein gluons）的产生截面乘以分支比设定了约束上限。通过与理论预言的产生截面对比，我们排除了顶色辅助色技模型中质量最高达3.1~3.6 TeV的Z'玻色子，排除了简化框架下质量区间为0.8 TeV至0.9 TeV以及2.0 TeV至2.2 TeV的暗物质传递者，并依据粒子自身衰变宽度排除了质量最高达3.4 TeV的卡鲁扎-克莱因胶子。