Abstract

The radiation in collider events, in particular within jets, contains much information. That radiation is exploited for studies of the Higgs sector, searches for new physics, understanding vacuum QCD, and investigating the properties of the quark-gluon plasma. Theorists have long used so-called Lund diagrams as a tool to help think about the kinematic regions within jets. A decade of work on devising observables for studying jets for Higgs and new-physics searches has recently led to the observation that one can formulate the Lund diagram as an experimental analysis tool. It provides a physically powerful representation of any given jet's structure and also remarkable insight also into features being learnt by AI-based jet tagging approaches.