Studies of the underlying event with ATLAS

Particle distributions sensitive to the underlying event have been measured with the ATLAS detector at the LHC. Charged particle multiplicity, charged and inclusive sum transverse momentum (pT) densities and mean charged-particle pT in the regions of each event, azimuthally transverse to the hardest jet, are presented. The underlying event properties are investigated for soft minimum bias events, events with hard jets and events associated with Z boson production. When compared to the predictions of different Monte Carlo models, the data show sensitivity to the modeling of the underlying event.