High-pT dijet angular distributions in pp interactions at $\sqrt{s}=$7 TeV measured with the ATLAS detector at the LHC

Dijet angular distributions from the first proton-proton collisions at center-of-mass energy $\sqrt{s}=$7 TeV have been measured with the ATLAS detector at the LHC. The data set used for this analysis represents an integrated luminosity of 61 ± 7 nb$^{−1}$, collected from March to July 2010. Dijet angular distributions and occupancy ratio distributions have been measured. Comparisons of these distributions with predictions from QCD show good agreement between data and QCD. A search for quark contact interactions has been performed, showing that they are excluded above a distance scale of 2.3 × 10$^{−4}$ fm with the available data. In addition, the data have been compared to QCD distributions summed with a template for physics beyond the Standard Model, allowing generic limits to be set on non-resonant new physics with isotropic dijet final states. For dijet masses between 520 and 680 GeV a ratio of potential signal over QCD background greater than 8% is excluded at the 95% confidence limit.