Search for New Physics in Dijet Mass Distributions in 0.81 fb^-1 of pp Collisions at sqrt(s) = 7 TeV

Invariant mass distributions of jet pairs (dijets) produced in LHC proton-proton collisions at a center-of-mass energy sqrt(s) = 7 TeV have been studied with the ATLAS detector using a data set acquired in 2011 with an integrated luminosity of 0.81 fb^-1. Dijet masses up to ∼4.0 TeV are observed in the data, and no evidence of resonance production over background is found. Improved limits have been set at 95% CL for several new physics hypotheses: excited quarks are excluded for masses below 2.91 TeV, axigluons are excluded for masses below 3.21 TeV, and color octet scalar resonances are excluded for masses below 1.91 TeV.