Studies of jet shapes and substructure with ATLAS

The internal structure of jets produced in proton-proton collisions at 7 TeV centre-of-mass energy at the LHC provides a direct test of QCD calculations of gluon and quark radiation, and is sensitive to soft QCD effects, such as hadronisation or underlying event. The transverse energy distribution around the jet core, as well as the fragmentation of a jet into charged particles, have been measured with the ATLAS detector. Jet shapes - including the jet mass - and jet substructure have the potential to identify jets coming from massive, boosted particles decaying hadronically. After applying techniques developed for reducing the sensitivity of jet properties to soft QCD and to multiple proton-proton collisions, a selection of variables is measured and compared to a range of QCD calculations and phenomenological models.