Physical Review Letters
Dijet angular distributions are measured over a wide range of dijet invariant masses in pp collisions at ffiffi s p ¼ 7 TeV, at the CERN LHC. The event sample, recorded with the CMS detector, corresponds to an integrated luminosity of 36 pb 1. The data are found to be in good agreement with the predictions of perturbative QCD, and yield no evidence of quark compositeness. With a modified frequentist approach, a lower limit on the contact interaction scale for left-handed quarks of þ ¼ 5:6 TeV ( ¼ 6:7 TeV) for destructive (constructive) interference is obtained at the 95% confidence level.
Khachatryan, V., Sirunyan, A. M., Tumasyan, A., Adam, W., Bergauer, T., Dragicevic, M., . . . Weinberg, M. (2011). Measurement of dijet angular distributions and search for quark compositeness in pp collisions at √s=7TeV. Physical Review Letters, 106(20)