Jonathan Butterworth, an experimental particle physicist, is head of the Physics and Astronomy Department at University College London. His current research is on the ATLAS experiment at the CERN Large Hadron Collider (LHC), where he has led a UCL group that contributed to the tracking, trigger, and software for the experiment. His work has focused on physics processes at the LHC that will help us discover more about electroweak symmetry breaking, or basically “why some things have mass.” This included searching for the Higgs boson, discovered in July 2012. Butterworth won the Chadwick Prize from the Institute of Physics in 2013 for his pioneering experimental and phenomenological work in high-energy particle physics, especially in the understanding of hadronic jets. He writes regularly for the Guardian; his book “Most Wanted Particle,” on the discovery of the Higgs, was published in 2014.