JOURNAL OF HIGH ENERGY PHYSICS, no.5, 2012 (SCI-Expanded)
A search for quark compositeness using dijet angular distributions from pp collisions at root s = 7TeV is presented. The search has been carried out using a data sample corresponding to an integrated luminosity of 2 : 2 fb(-1), recorded by the CMS experiment at the LHC. Normalized dijet angular distributions have been measured for dijet invariant masses from 0.4TeV to above 3TeV and compared with a variety of contact interaction models, including those which take into account the effects of next-to-leading-order QCD corrections. The data are found to be in agreement with the predictions of perturbative QCD, and lower limits are obtained on the contact interaction scale, ranging from 7.5 up to 14.5TeV at 95% confidence level.