New long-lived particles (LLPs) are a feature of many extensions to the Standard Model (SM), and their unique detector signatures may elude searches for promptly decaying particles. If a new, neutral LLP decays hadronically in the outer layers of the calorimeter, it produces sprays of collimated particles called “displaced” jets, with unusual features compared to their SM counterparts. This seminar aims to provide an introduction to the field of LLP searches in collider experiments. This is further illustrated by presenting an analysis of data collected in pp collisions at √s = 13 TeV with the ATLAS detector focusing on identifying displaced jets produced in association with a SM W boson decaying leptonically.