Search for new Physics in the dijet mass spectrum and dijet ratio in pp Collisions at sqrt(s) = 7 TeV

A search for new Physics is performed with inclusive dijet final states in pp collisions, using data corresponding to an integrated luminosity of $120\pm13$~nb$^{-1}$ collected by the CMS experiment at LHC. Generic upper limits at the 95\% confidence level (CL) are presented on the product of the resonance cross section, branching fraction into dijets, and acceptance, separately for decays into quark-quark, quark-gluon, or gluon-gluon pairs. The data exclude new particles predicted in the following models at the 95\% CL: string resonances, with mass less than $1.67$~TeV, excited quarks, with mass less than $0.59$~TeV and axigluons and colorons with mass less than $0.52$ TeV. A search for quark compositeness in the form of quark contact interactions is conducted using the dijet centrality ratio, which quantifies the angular distribution of the dijets. The measurement is found to agree with the predictions of the Standard Model and the statistical analysis of the data provides a lower limit on the energy scale of quark contact interactions of $1.9$~TeV at the 95\% confidence level. The above results extend previously published limits on these models.