Measurement of dijet production with a jet veto at ATLAS

This contribution to the 2011 Low-x meeting presents ATLAS measurements that provide accurate tests of perturbative QCD radiation models in dijet systems in two limits: large jet rapidity separation and large jet transverse momentum. Two observables are studied with LHC proton-proton collisions at sqrt{s} = 7 TeV: in the rapidity region bounded by the dijet system the mean jet multiplicity and the fraction of dijet events that do not contain an additional jet are measured. The analysis was performed using 38 +- 4 pb^{-1} of data taken by ATLAS in the year 2010.