1,721,343 research outputs found
Resistive Plate Chambers in Avalanche Mode: a Comparison Between Model Predictions and Experimental Results
No full textDesign of a constant fraction discriminator for the VFAT3 front-end ASIC of the CMS GEM detector
No full textIn this work the design of a constant fraction discriminator (CFD) to be used in the VFAT3 chip for the read-out of the triple-GEM detectors of the CMS experiment, is described. A prototype chip containing 8 CFDs was implemented using 130 nm CMOS technology and test results are shown
Measurement of the properties of a Higgs boson in the four-lepton final state
No full textThe properties of a Higgs boson candidate are measured in the H -> ZZ -> 4l decay channel, with l = e, mu, using data from pp collisions corresponding to an integrated luminosity of 5.1 fb(-1) at the center-of-mass energy of root s = 7 TeV and 19.7 fb(-1) at ffiffiffi root s = 8 TeV, recorded with the CMS detector at the LHC. The new boson is observed as a narrow resonance with a local significance of 6.8 standard deviations, a measured mass of 125.6 +/- 0.4(stat) +/- 0.2(syst) GeV, and a total width <= 3.4 GeV at the 95% confidence level. The production cross section of the new boson times its branching fraction to four leptons is measured to be 0.93(-0.23)(+0.26) (stat)(-0.09)(+0.13) (syst) times that predicted by the standard model. Its spin-parity properties are found to be consistent with the expectations for the standard-model Higgs boson. The hypotheses of a pseudoscalar and all tested spin-1 boson hypotheses are excluded at the 99% confidence level or higher. All tested spin-2 boson hypotheses are excluded at the 95% confidence level or higher
Fiber Bragg Grating (FBG) sensors as flatness and mechanical stretching sensors
No full textA novel approach which uses Fiber Bragg Grating (FBG) sensors has been utilized to assess and monitor the flatness of Gaseous Electron Multipliers (GEM) foils. The setup layout and preliminary results are presented
Measurement of the production cross section in the dilepton channel in pp collisions at = 8 TeV
No full textErratum to: Search for new physics in events with same-sign dileptons and jets in pp collisions at (Formula presented.) = 8 TeV
No full textMeasurement of pseudorapidity distributions of charged particles in proton–proton collisions at (Equation Present) TeV by the CMS and TOTEM experiments
No full textPseudorapidity (eta) distributions of charged particles produced in proton-proton collisions at a centre-of-mass energy of 8 TeV are measured in the ranges vertical bar eta vertical bar < 2.2 and 5.3 < vertical bar eta vertical bar < 6.4 covered by the CMS and TOTEM detectors, respectively. The data correspond to an integrated luminosity of L = 45 mu b(-1). Measurements are presented for three event categories. The most inclusive category is sensitive to 91-96 % of the total inelastic proton-proton cross section. The other two categories are disjoint subsets of the inclusive sample that are either enhanced or depleted in single diffractive dissociation events. The data are compared to models used to describe high-energy hadronic interactions. None of the models considered provide a consistent description of the measured distributions
Development and performance of triple-gem detectors for the upgrade of the muon system of the cms experiment
No full textThe CMS Collaboration is evaluating GEM detectors for the upgrade of the muon system. This contribution will focus on the R&D performed on chambers design features and will discuss the performance of the upgraded detector
Search for a Higgs boson decaying into a Z and a photon in pp collisions at sqrt(s) = 7 and 8 TeV
No full textA search for a Higgs boson decaying into a Z boson and a photon is described. The analysis is performed using proton-proton collision datasets recorded by the CMS detector at the LHC. Events were collected at center-of-mass energies of 7 TeV and 8 TeV, corresponding to integrated luminosities of 5.0 and 19.6 inverse femtobarns, respectively. The selected events are required to have opposite-sign electron or muon pairs. No excess above standard model predictions has been found in the 120-160 GeV mass range and the first limits on the Higgs boson production cross section times the H to Z gamma branching fraction at the LHC have been derived. The observed at 95% confidence level limits are between about 4 and 25 times the standard model cross section times the branching fraction. For a standard model Higgs boson mass of 125 GeV the expected limit at the 95% confidence level is 10 and the observed limit is 9.5. Models predicting the Higgs boson production cross section times the Higgs to Z gamma branching fraction to be larger than one order of magnitude of the standard model prediction are excluded for most of the 125-157 GeV mass range
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