Until 2004 I worked on ZEUS experiment at the HERA electron proton collider at DESY in Hamburg. I made first measurements of hadronic jet photoproduction. I was physics chair of the experiment in 2003-2004. I led efforts to translate HERA data to have an impact at the CERN Large Hadron Collider (LHC), including writing the widely used "JIMMY" programme to simulate multiparton interactions.

I now work on the ATLAS experiment at the LHC. I led a group which contributed to the tracking, trigger and software. My own work has focussed on physics processes at the LHC which will help us discover more about electroweak symmetry breaking, or basically "why some things have mass". This included searching for the infamous standard model Higgs boson, discovered in July 2012. I wrote some of the first papers on using the substructure of hadronic jets to identify the decays of boosted, massive particles - including the Higgs. I was convener of the ATLAS Monte Carlo group (2007-2009) and of the ATLAS Standard Model group (2010-2012).