论文标题
在$ \ sqrt {s} = 13 $ tev中搜索$ pp $ collisions中的中性长寿命颗粒
Search for neutral long-lived particles in $pp$ collisions at $\sqrt{s}=13$ TeV that decay into displaced hadronic jets in the ATLAS calorimeter
论文作者
论文摘要
使用139 fb $^{ - 1} $在2015 - 2018年以13 tev的中心能量为13 TEV的LHC，搜索了对成对产生的中性长寿命颗粒（LLP）的腐烂（LLP）。开发了专门的技术，用于重建在Atlas Hadronic量热计中LLPS产生的LLP产生的流离失所喷气机。针对不同的LLP运动学制度定义了两个搜索区域。观察到的事件数量与预期背景一致，并确定了几个基准信号的限制。对于质量为125 GEV的SM Higgs玻色子，根据$ C $ C $ times LLP的值，分支比以95％的置信度排除在95％的置信度水平下，根据模型，在20 mm至10 m之间的范围内，将其在20 mm至10 m之间。在质量为60 GEV的标量和200 GEV和1 TEV之间的质量的标量的横截面时间分支比率上也设置了上限。
A search for decays of pair-produced neutral long-lived particles (LLPs) is presented using 139 fb$^{-1}$ of proton-proton collision data collected by the ATLAS detector at the LHC in 2015-2018 at a centre-of-mass energy of 13 TeV. Dedicated techniques were developed for the reconstruction of displaced jets produced by LLPs decaying hadronically in the ATLAS hadronic calorimeter. Two search regions are defined for different LLP kinematic regimes. The observed numbers of events are consistent with the expected background, and limits for several benchmark signals are determined. For a SM Higgs boson with a mass of 125 GeV, branching ratios above 10% are excluded at 95% confidence level for values of $c$ times LLP mean proper lifetime in the range between 20 mm and 10 m depending on the model. Upper limits are also set on the cross-section times branching ratio for scalars with a mass of 60 GeV and for masses between 200 GeV and 1 TeV.
