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

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.