"$p_{T}^{miss}$ in the AH $1e$ W CR" of "Search for dark matter produced in association with a single top quark or a top quark pair in proton-proton collisions at $ \sqrt{s}=13 $ TeV"

A search for dark matter produced in association with top quarks in proton-proton collisions at a center-of-mass energy of 13 TeV is presented. The data set used corresponds to an integrated luminosity of 35.9 fb-1 recorded with the CMS detector at the LHC. Whereas previous searches for neutral scalar or pseudoscalar mediators considered dark matter production in association with a top quark pair only, this analysis also includes production modes with a single top quark. The results are derived from the combination of multiple selection categories that are defined to target either the single top quark or the top quark pair signature. No significant deviations with respect to the standard model predictions are observed. The results are interpreted in the context of a simplified model in which a scalar or pseudoscalar mediator particle couples to a top quark and subsequently decays into dark matter particles. Scalar and pseudoscalar mediator particles with masses below 290 and 300 GeV, respectively, are excluded at 95% confidence level, assuming a dark matter particle mass of 1 GeV and mediator couplings to fermions and dark matter particles equal to unity.

本文报道了一项在质心系能量13 TeV的质子-质子碰撞中，搜索伴随顶夸克（top quark）产生的暗物质（dark matter）的研究。本研究使用的数据集源自大型强子对撞机（Large Hadron Collider, LHC）上的紧凑型μ子螺线管探测器（Compact Muon Solenoid, CMS）采集的35.9 fb⁻¹积分亮度数据。相较于此前仅针对伴随顶夸克对产生的暗物质展开的中性标量或赝标量媒介子搜索工作，本分析还纳入了单顶夸克伴随产生的暗物质生成模式。分析结果基于多类分别针对单顶夸克或顶夸克对信号特征定义的选择范畴的联合分析得到。未观测到与标准模型（Standard Model）预言存在显著偏离的信号。本结果在一个简化模型框架下进行解释：该模型中，标量或赝标量媒介子与顶夸克发生耦合，并随后衰变为暗物质粒子。在暗物质粒子质量为1 GeV、媒介子与费米子（fermion）及暗物质粒子的耦合强度均为1的假设下，质量分别低于290 GeV和300 GeV的标量媒介子与赝标量媒介子在95%置信水平下被排除。