[PDF] Top 20 Measurement of the top-quark mass in all-jets tt events in pp collisions at root s=7 TeV

... colleagues in the CERN accelerator departments for the excellent performance of the LHC and thank the technical and administrative staffs at CERN and at other CMS ... See full document

... After the subtraction of the backgrounds, an unfolding procedure is used to correct the re- constructed distributions for detector-specific effects, ...to the parton or particle level. ... See full document

... 70% of the selected tt events belong to the lepton+jets final state at generator ...level. The reconstructed top quark is matched to the ... See full document

... and at least two jets. Both the lepton-based asymmetry A `` C and the t¯ t asymmetry A t¯ C t are extracted in three channels: ee, eµ and ...µµ. The mea- surement of A t¯ ... See full document

... response of the CMS calorimetric system to neutral ...well-measured in the tracker and in the ECAL, and do not need such ...However, the resulting jets require ... See full document

... produced at the Large Hadron Collider (LHC) primarily through gluon-gluon ...fusion. The measurements of the tt production cross section and branch- ing fractions are important ... See full document

... and the number of b-tagged ...excess of events is observed above the expected standard model ...set at 95% confidence level for simplified models of direct top ... See full document

... range of jet multiplicities without the need to measure all the additional ...description of multiple-parton radiation is still lacking in perturbative QCD ...account in ... See full document

... section of t-channel single-top-quark production has been measured in pp collisions using 2011 data in semileptonic top-quark decay modes with improved ... See full document

... feature of the Compact Muon Solenoid (CMS) detector is a superconducting solenoid, 13 m in length and 6 m in diameter, which provides a uniform axial magnetic field of ...T. The ... See full document

... and the MLM prescription [18] is used for matching of matrix-element jets to parton ...showers. The Lund string model [19] is used for the simulation of the hadronization, ... See full document

... From the list of possible reconstructions in each event, we choose the hypothesis that best matches the assumption of a tt ...interpretation. In simulated tt ... See full document

... exploits the long lifetime and relatively large mass of b hadrons to provide optimized b-quark jet ...discrimination. The CSV algorithm combines information about impact parameter ... See full document

... Z(``)+jets events, in which the Z bosons have kinematic properties very similar to those in the search sample, after correcting for the difference in acceptance ... See full document

... pair events relies on detector simula- tion. To evaluate the uncertainty event-based efficiency values are instead constructed from single-muon ...efficiencies. The single-muon efficiencies are ... See full document

... study, the level of the background is best estimated using a data-driven method, rather than by MC simulation where the number of events is low and the backgrounds may be ... See full document

... that the fits are unbiased and return correct statistical uncertain- ties. The widths of pull distributions are consistent with ...to the use of Pythia to generate templates and mc@nlo ... See full document

... simulated events. The MADGRAPH5 ...parton-level events with a W boson and up to four partons on the basis of matrix-element (ME) ...used the ALPGEN generator [18].) The ... See full document

... model top quark and a vector-like quark partner T has been ...presented. The data used in this search were recorded with the CMS detector at the LHC at √ ... See full document

... system of two equations, expressing the number of W + 1 jet events and W + 2 jets events before and after b-tagging, can be written with six independent flavour fractions as ... See full document