Leptoquarks at Atlas Run 3

轻子夸克是携带夸克和轻子量子数的粒子。轻子和夸克扇区的相似性在理论上激发了轻子夸克。它们是许多超越标准模型的模型的一个特征，特别是处理统一的模型：超对称性（SUSY），Technicolor等。他们也可以有助于μ子g-2异常磁矩的理论和实验之间的差异。博士项目的目的是进行一个新的leptoquark对搜索，使用多变量技术，并专注于多TeV的质量制度，以获得最好的运行III数据集。分析将包括所有可能的轻子-夸克组合，除了那些与第三代费米子的组合-总共将研究25种可能的衰变。轻子夸克衰变与中微子将被包括在内。在高能量下μ子动量分辨率较差，这些将被包括在分析中。对分析的主要改进是使用多变量技术。以前，两个leptoquark的平均质量被用作最终判别。这在分析得到优化的低质量状态下是足够的。对于新的分析，在高质量状态下，计划使用多输入观测值，通过多变量技术和可能的图形神经网络，可以更好地区分信号和背景事件。在涉及中微子或μ子分辨率差的衰变中，质量不能完全重建，而是必须将几个最终状态观测值进行优化组合。ATLAS的目标是将当前基于RNN的Tau ID和衰变模式分类算法升级为基于GNN的架构。目前，有两种解决方案：TauJetGraph和GNTau。作为鉴定任务的一部分，将对两种GNN进行研究，以评估性能差异。目标是正式实施并部署到ATLAS框架中，之后需要进行基于数据的评估

Leptoquarks are particles that carry both quark and lepton quantum numbers. Leptoquarks are theoretically motivated by similarities in the lepton and quark sector. They are a feature of many models that go beyond the Standard Model, particularly models dealing with unification: SUSY (Supersymmetry), Technicolor, etc. Leptoquarks are a possible explanation of anomalies observed in B-meson decays, given their unique ability to mediate lepton flavour universality violation. They can also contribute to the muon g-2 anomalous magnetic moment discrepancy between theory and experiment.The PhD project aims to conduct a new leptoquark pair search that uses multi-variant techniques and focus on the multi-TeV mass regime to get the best out of the Run III dataset. The analysis will include all possible lepton-quark combinations apart from those with third generation fermions - a total of 25 possible decays will be investigated. Leptoquark decays with neutrinos will be included. Muon momentum resolution is poor at high energy, these will be included in the analysis.The major improvement to the analysis is to use multivariant techniques. Previously, the average mass of the two leptoquarks was used as the final discriminant. This was adequate in the low mass regime where the analysis was optimised. For the new analysis, in the high mass regime, the plan is to use multiple input observables that can better discriminate signal from background events through multivariate techniques and possible graph neural networks. The mass cannot be fully reconstructed in decays involving neutrinos or where the muon resolution is poor, instead several final state observables must be optimally combined.ATLAS is aiming to upgrade the current RNN based algorithm for Tau ID and decay mode classification to a GNN based architecture. Currently, there are two proposed solutions: TauJetGraph and GNTau. As part of the qualification task, a study of the two GNN's will be conducted to evaluate the performance differences. The goal is to implement and deploy officially into the ATLAS framework, subsequent to this a data-based evaluation will need to be performed