Search for flavor-changing neutral currents in top quark decays $t\to Hc$ and $t \to Hu$ in multilepton final states in proton-proton collisions at $\sqrt{s}= 13$ TeV with the ATLAS detector
Flavor-changing neutral currents are not present in the Standard Model at tree level and are suppressed in loop processes by the unitarity of the Cabibbo-Kobayashi-Maskawa matrix; the corresponding rates for top quark decay processes are experimentally unobservable. Extensions of the Standard Model can generate new flavor-changing neutral current processes, leading to signals which, if observed, would be unambiguous evidence of new interactions. A dataset corresponding to an integrated luminosity of 36.1 fb$^{-1}$ of $pp$ collisions at a center-of-mass energy of $\sqrt{s}=$ 13 TeV recorded with the ATLAS detector at the Large Hadron Collider is used to search for top quarks decaying to up or charm quarks with the emission of a Higgs boson, with subsequent Higgs boson decay to final states with at least one electron or muon. No signal is observed and limits on the branching fractions $\mathcal{B}(t \to Hc) <$ 0.16% and $\mathcal{B}(t \to H u) <$ 0.19% at 95% confidence level are obtained (with expected limits of 0.15% in both cases).
Measurement of the $t\bar{t}Z$ and $t\bar{t}W$ production cross sections in multilepton final states using 3.2 fb$^{-1}$ of $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
Search for Beyond the Standard Model physics with anomaly detection in multilepton final states in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN)（欧洲核子研究中心（CERN））
Search for top quark flavor-changing neutral currents in multilepton final states using an effective field theory approach in proton--proton collisions at $\sqrt{s}$ = 13 TeV
Measurement of the Higgs boson production in association with top quarks in multilepton final states in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
Search for singly produced vector-like top partners in multilepton final states with 139 $\mathrm{fb}^{-1}$ of $pp$ collision data at $\sqrt{s} = 13$ TeV with the ATLAS detector
A search for electroweak $t\bar{t}Wj$ production in multileptonic final states at $\sqrt{s} = 13$ TeV with the ATLAS detector and bounds on effective field theory operators
EUROPEAN ORGANISATION FOR NUCLEAR RESEARCH (CERN)（欧洲核子研究组织（CERN））
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
Topping-up multilepton plus b-jets anomalies at the LHC with a $Z'$ boson
在过去的几年中，ATLAS和CMS报告了在$t\bar t H$、$t\bar t W^\pm$、$t\bar t Z$和$t\bar t t\bar t$等分析中，多重轻子加上$b$ -喷流的特征的一些轻微到轻微的差异。其中，最近ATLAS关于$t\bar t H$产生的结果也报道了具有两个或更多$b$标记喷流的同号双轻子通道中的电荷不对称性。受这些诱人的差异的启发，我们研究了一个唯象的新物理模型，该模型由一个通过右手流耦合到上型夸克的$Z'$玻色子组成：$t_Rγ^μ\bar t_R$，$t_Rγ^μ\bar c_R$和$t_R γ^μ\bar u_R$。后一个顶点允许将LHC初始状态质子的电荷不对称性转化为顶夸克的最终状态，顶夸克衰变为正轻子和$b$ -喷流，为观察到的一些差异提供了至关重要的贡献。通过在检测器水平上的分析，我们选择了我们的模型的参数空间中的区域，该区域最好地再现了上述$t\bar t H$研究和最近的ATLAS $t\bar t t \bar t$搜索中的数据。我们发现，我们的模型提供了一个更好的拟合实验数据比标准模型的新物理尺度约$\sim$ 500 GeV，并与分层耦合的$Z'$玻色子，有利于顶夸克和FCNC电流的存在。为了估计LHC对该信号的灵敏度，我们设计了一个宽带搜索，其特征在于具有不同信号背景比的许多运动区域，并进行全局分析。我们还定义了信号增强…
Searches for heavy Higgs bosons in two-Higgs-doublet models and for t to ch decay using multilepton and diphoton final states in pp collisions at 8 TeV
Search for four-top-quark production in the single-lepton and opposite-sign dilepton final states in pp collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
Measurement of cross-sections for production of a $Z$ boson in association with a flavor-inclusive or doubly $b$-tagged large-radius jet in proton-proton collisions at $\sqrt{s} = 13$ TeV with the ATLAS experiment
Search for chargino and neutralino production in final states with a Higgs boson and missing transverse momentum at $\sqrt{s} = 13$ TeV with the ATLAS detector
Evidence for the associated production of the Higgs boson and a top quark pair with the ATLAS detector
本文报道了用顶夸克对（$t\bar t H$）研究希格斯玻色子的关联产生.搜索是在多轻子的最终状态使用的数据集对应于一个综合光度为36.1 FB $^{-1}$质子-质子碰撞数据记录的ATLAS实验在一个中心的质量能量$\sqrt{s} = 13$ TeV的大型强子对撞机。目标是希格斯玻色子衰变为$WW^*$、$ττ$和$ZZ^*$。七个最终状态，分类的数量和口味的带电轻子候选人，检查的存在下，标准模型希格斯玻色子的质量为125 GeV和一对顶夸克。超过标准模型过程预期背景的事件过多，观察到的显著性为4.1标准差，而预期为2.8标准差。$t\bar t H$产生截面的最佳拟合是$σ(t\bar t H) = 790^{+230}_{-210}$ fb，与标准模型预测的$507^{+35}_{-50}$ fb一致。该结果与来自ATLAS实验的使用希格斯玻色子衰变模式到$b\bar b$、$γγ$和$ZZ^* \to 4\ell$的其他$t\bar t H$搜索的组合具有4.2标准差的观察显著性，而预期为3.8标准差。这为$t\bar t H$生产模式提供了证据。
Measurement of the suppression and azimuthal anisotropy of muons from heavy-flavor decays in Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}} = 2.76$ TeV with the ATLAS detector
利用ATLAS测量了LHC上$\sqrt{s_{\mathrm{NN}}} = 2.76$ TeV Pb+Pb碰撞和$\sqrt{s} = 2.76$ TeV $pp$碰撞中重味衰变产生μ子的过程。积分光度为0.14 $\mathrm{nb}^{-1}$和570 $\mathrm{nb}^{-1}$分别用于Pb+Pb和$pp$测量，这是在μ子横向动量范围$4 < p_{\mathrm{T}} < 14$ GeV和5个Pb+Pb中心间隔进行。从飞行中的π介子和K介子衰变，强子簇射，和错误重建的μ介子所产生的背景统计删除使用模板拟合程序。在$pp$和Pb+Pb碰撞中分别测量了重味μ子微分截面和每事件产额。从这些得到的核修正因子$R_{\mathrm{AA}}$被观察到是独立的$p_{\mathrm{T}}$，在不确定性内，并小于1，这表明抑制生产重味μ子在Pb+Pb碰撞。对于10%最中心的Pb+Pb事件，测得的$R_{\mathrm{AA}}$约为0.35。还测量了重味μ子产额的方位角调制，并给出了$n =$ 2，3和4的相关傅立叶系数$v_n$作为$p_{\mathrm{T}}$和中心性的函数。它们随$p_{\mathrm{T}}$缓慢变化，并表现出随中心性的系统变化，这是其他各向异性测量的特征，例如对包容性强子所观察到的。测量的$R_{\mathrm{AA}}$和$v_n$值也与理…
Search for heavy neutral leptons in decays of $W$ bosons using a dilepton displaced vertex in $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector
Search for 1st-Generation Leptoquarks Using the ATLAS Detector
本文报道了在LHC记录的7 TeV ATLAS数据的1/fb中寻找标量细夸克对产生的结果。轻夸克是一种假设的三重色玻色子，它同时带有夸克和轻子的味道，因此衰变为夸克和轻子，与任何标准模型粒子不同。轻夸克产生于许多超越标准模型的理论。在这个分析中检查的通道需要至少一个轻夸克衰变到电子，其中包括最终状态eejj和evjj。没有多余的事件被观察到，从而限制允许leptoquark质量被确定。我们在95%的置信水平上排除了质量m < 660（607）GeV的第一代标量细夸克的产生，假设细夸克衰变到电子的分支分数为1.0（0.5）。
Searches for electroweak production of supersymmetric particles with compressed mass spectra in $\sqrt{s}=13$ TeV $pp$ collisions with the ATLAS detector
