Search for QCD Instantons at the LHC using the ATLAS detector

一系列尚未解决的实验和理论问题表明，标准模型并不是关于物质和力的最终理论。超对称（SUSY）是标准模型的一个受欢迎的扩展，它解决了许多当前的问题。该理论预测每个费米子都有一个玻色子伴侣，反之亦然。如果存在这样的超对称伴侣粒子，它们应该具有TeV尺度的质量，应该在大型强子对撞机中产生，并且可以通过ATLAS找到。最近ATLAS对希格斯玻色子的发现进一步增加了tev尺度超对称的动机。这个研究项目扩展了ATLAS对这类粒子的搜索。目标：发现新的超对称伙伴；探索结果的现象学后果目标：为ATLAS探测器的维护和运行做出贡献改善lhc Run-3的物理对象的触发或重建为一篇或多篇搜索论文提供主要贡献在超对称模型中为这些结果提供一种或多种解释研究将使用最近完成的Run-2数据集结合最新的最先进的机器学习技术来提高灵敏度。它将扩展牛津ATLAS小组最近的研究成果，包括对higgsinos、夸克、睡眠子和胶子的研究。在某些参数空间区域，LHC实验在收集了140/fb的综合光度后，才开始达到超过上一代LEP e+e-实验的灵敏度。特别是在这些区域，例如以低横截面和压缩的质谱为特征，预计大部分研究将集中在这些区域。其他可能性包括规范中介模型或违反r宇称的模型。该研究是与我们在欧洲核子研究中心的ATLAS实验上的全球合作伙伴合作进行的。ATLAS是大型强子对撞机的两个通用探测器之一。牛津大学的研究小组为ATLAS探测器的建造做出了贡献，并继续集中参与其操作，特别是在半导体跟踪器、丢失动量触发算法以及射流、丢失动量和μ子的重建方面。

A range of unresolved experimental and theoretical issues suggest that the Standard Model is not the final theory of matter and forces. Supersymmetry (SUSY) is one example of a favoured extension of the Standard Model, and one which solves many of its current problems. The theory predicts that every fermion has a bosonic partner and vice-versa. If such supersymmetric partner particles exist, they ought to have masses at the TeV scale, and should be produced in the LHC and can be found by ATLAS. The recent discovery by ATLAS of a Higgs boson further increases the motivation for TeV-scale supersymmetry. This research programme extends the ATLAS searches for such particles.Aims:Discovery new supersymmetric partners, or place tight experimental constraints the theoretical models which propose themExplore the phenomenological consequences of the resultsObjectives:Contribute to the maintenance and operation of the ATLAS detectorImprove the triggering or reconstruction of physics objects for Run-3 of the LHCProvide a leading contribution to one or more search papersContribute to one or more interpretations of these results within supersymmetric modelsThe research will use the recently completed Run-2 dataset from the LHC together with the latest in state-of-the-art machine learning techniques to increase sensitivity. It will extend recent results in which the Oxford ATLAS group has had a central role, including searches for higgsinos, squarks, sleptons and gluinos. There are regions of parameter space in which the LHC experiments, after collectiong 140/fb of integrated luminosity are only starting to achieve sensitivity beyond the previous generation of LEP e+e- experiments. It is particularly in these regions, characterised for example by low cross-sections and compressed mass spectra, in which it is anticipated that the bulk of the research will be focused. Other possibilities include gauge-mediate models or models with R-parity violation.Any companies or collaborations involvedThe research is performed in collaboration with our global partners on the ATLAS experiment at CERN. ATLAS is one of two general-purpose detectors at the LHC. The Oxford group contributed to the construction of the ATLAS detector, and continues to be centrally involved in its operation, particularly in the semiconductor tracker, the missing-momentum trigger algorithms, and the reconstruction of jets, missing momentum and muons.