Speaker
Description
This contribution presents the status of an ongoing ATLAS analysis of jet substructure in Z+jet events in heavy-ion and proton-proton collisions at the energy of 5.36 TeV. The study utilizes Z bosons reconstructed through their dilepton decay channels and examines jet substructure observables to investigate modifications of the parton shower in the quark-gluon plasma – extremely hot and dense medium created in ultra-relativistic heavy-ion collisions. In particular, jets produced in association with a Z boson offer a clean experimental probe, as the electroweak boson does not interract with the medium via strong interaction and thus, it provides an estimate of the initial parton kinematics. In addition, Z-tagged jets are predominantly quark-initiated, which is extremely useful for testing QCD predictions for quark-jet substructure.