Search for Narrow Resonances using the Dijet Mass Spectrum in pp Collisions at sqrt s of 7 TeV

We present a search for new particles decaying to a pair of jets %studying the dijet mass spectrum in pp collisions at $\sqrt{s}=7$~TeV. The data sample for events with dijet invariant mass above 0.9 TeV corresponds to an integrated luminosity of 5 fb$^{-1}$ collected by the CMS detector at the LHC. In order to extend the sensitivity in the 0.6--0.9~TeV range, a complementary low-mass analysis is performed employing a special dataset with reduced event content, corresponding to an integrated luminosity of 0.13 fb$^{-1}$ and collected in the last days of the 2011 data taking period. %has been used for the low mass analysis. %The dijet mass distribution of the two leading jets is measured %and compared to QCD predictions from PYTHIA propagated %through the CMS detector simulation. %after requiring the pseudorapidity separation of the two jets %to satisfy $|\Delta\eta| < 1.3$ with each jet inside the region %$|\eta|< 2.5$. The measured dijet mass spectrum is fitted with a smooth, empirical %parametrization which well describes the prediction from simulated QCD dijet events. %We search for narrow dijet resonances and we see no significant excess %of events above the background expectation in the entire mass range explored. %We therefore set upper limits at 95\% confidence level on the %resonance cross section times branching fraction in dijets times acceptance. %By comparing these generic limits with theoretical leading-order predictions for the %cross section of several models of new particles, We set specific lower limits on the mass of string resonances, excited quarks, axigluons, colorons, s8 resonances, $\mbox{E}_{6}$ diquarks, W' and Z' bosons, and RS gravitons in the 0.6--4.3 \TeV range, most of which extend previous exclusions from the dijet mass search technique.