Jet Production Measurements at CMS (1312.1813v1)

Abstract: Jet production cross-section measurements are presented. The measurements are done with the data from Large Hadron Collider (LHC) proton-proton collisions, collected with the Compact Muon Solenoid (CMS) detector. The inclusive jet production measurements are carried out with data collected $\rm \sqrt{s} ~= ~7 ~TeV$ and $\rm 8~TeV$ with total integrated luminosity ($\mathcal{L}{int}$) $\rm 5.0~ fb^{-1}$ and $\rm 10.71~ fb^{-1}$ respectively. The dijet production measurements are carried out with the $\rm \sqrt{s}~ =~ 7 ~TeV$ dataset. Jets are reconstructed with the anti-$k_T$ clustering algorithm with size parameter $R=0.7$. The measured cross sections are corrected for detector effects and compared to perturbative QCD predictions at NLO, corrected for NP factors, using various sets of PDF. The inclusive jet cross-section ratio of the jets reconstructed with the anti-$k_T$ (AK) algorithm and two radius parameter $\rm R~=~0.5$ and $\rm R~=~0.7$ are also presented. The data used is $\rm \sqrt{s}~ =~ 7 ~TeV$ CMS data corresponding to $\rm \mathcal{L}{int}~=~5.0 ~fb^{-1}$. Significant discrepancies are found comparing the data to leading order calculations and to fixed order calculations at NLO, corrected for NP effects, whereas simulations with NLO matrix elements matched to the parton showers describe the data quite well. A study of color coherence effects in pp collisions has been performed with the data collected at $\rm \sqrt{s}~ =~ 7~TeV$ and $\rm\mathcal{L}_{int}~=~ 36~pb^{-1}$. The measurement of the azimuthal angular correlation between the second and third jets is compared to the predictions of Monte Carlo models with different implementations of color coherence effects.