Speaker: Ibrahim Chahrour, University of Michigan 

Title: QCD Jets 

Abstract: The substructure of QCD jets has garnered significant attention with the advent of infrared and collinear safe clustering algorithms and observables. A key question emerging from these studies is how in-jet emissions at soft and hard energy scales, across various angles, differ with the mass of the emitting parton. The Lund jet plane (LJP) is a perturbatively well-defined substructure observable that maps the radiation pattern of jets onto a 2D plane, visually distinguishing emissions with different kinematics. Comparing the LJP for jets containing hadrons of low versus high mass enables the testing of QCD splitting functions from first-principles calculations across both soft and hard regimes and at different radiation angles. An experimental representation of the LJP is constructed by reclustering jets using the Cambridge/Aachen algorithm and then declustering them along the hardest/heavy-flavor branch, recording each consecutive emission. In this talk, I will present the first measurement of the LJP for charm- and beauty-initiated jets at $sqrt{s} = 13$ TeV at LHCb. Mass effects are observed in the collinear region of the LJP through the dead cone effect.