"Table 7" 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, LHC）上ATLAS探测器（ATLAS Detector）采集的质心系能量$sqrt{s}$=13 TeV、积分亮度36.1 fb⁻¹的质子-质子碰撞数据，开展了对衰变至顶夸克（top quark）对的新粒子的搜寻工作。通过筛选多个高横动量喷注（其中包含含b强子的喷注），选取与顶夸克对产生过程以及顶夸克全强子衰变模式相符的事例。本研究采用两种分析技术，分别针对不同运动学区域的顶夸克对重建进行优化，以提升对宽质量范围内假想新粒子的搜寻灵敏度。对两个重建顶夸克候选事例的不变质量分布进行分析，以搜寻不同自旋与衰变宽度的新粒子共振产生信号。未观测到与标准模型（Standard Model, SM）预言存在显著偏差的信号，并对假想的$Z^{prime}$玻色子（Z' boson）、暗物质媒介子（dark-matter mediator）、卡鲁扎-克莱因引力子（Kaluza-Klein gravitons）以及卡鲁扎-克莱因胶子（Kaluza-Klein gluons）的产生截面与分支比乘积设置了约束。通过与理论预言的产生截面对比，本研究排除了顶色辅助技术色模型（topcolor-assisted-technicolor model）中质量上限达3.1−3.6 TeV的$Z^{prime}$玻色子；排除了简化框架下质量处于0.8 TeV至0.9 TeV以及2.0 TeV至2.2 TeV区间的暗物质媒介子；同时依据粒子衰变宽度的不同，排除了质量上限达3.4 TeV的卡鲁扎-克莱因胶子。