Searches for lepton number and lepton flavour violating phenomena in high energy electroweak interactions with the ATLAS experiment

学生将使用完整的Run-2质子-质子碰撞数据集在ATLAS实验中对高能电弱矢量玻色子融合/矢量玻色子散射相互作用中的一系列轻子数和轻子味违反现象进行新颖的搜索。第一份出版物将侧重于建立正在研究的双μ子终态的一般技术和模型，然后在随后的数据分析和出版物中探索双τ和混合轻子味终态。未来可能的扩展包括扩展研究计划，使用ATLAS结合AFP光谱仪探测光子融合相互作用中类似的新现象。为了支持这些搜索，特别是tau和混合轻子搜索，学生将在运行3和HL-LHC升级数据采集阶段的ATLAS实验中为增强tau重建和识别算法做出贡献。特别是，学生将开发新的机器学习工具，以协调tau ID到一个单一的算法分类五个不同的衰减模式和多射流背景，并最终提高性能。

The student will perform novel searches for a series of lepton number and lepton flavour violating phenomena in high-energy electroweak vector boson fusion / vector boson scattering interactions at the ATLAS experiment using the full Run-2 proton-proton collision dataset. The first publication will focus on establishment of the general techniques and models under study on the di-muon final state, before exploring di-tau and mixed lepton flavour final states in subsequent data analyses and publications. Potential future extensions include expansion of the research programme to probe similar new phenomena in photon-fusion interactions using ATLAS in conjunction with the AFP spectrometer.To support these searches, in particular the tau and mixed-lepton searches, the student will contribute to the enhancement of tau reconstruction and identification algorithms across the ATLAS experiment for Run-3 and HL-LHC upgrade data-taking phases. In particular, the student will develop new machine learning tools to harmonise tau ID into a single algorithm classifying five distinct decay modes and multijet backgrounds, and ultimately improve performance.