Search
Results
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Alignment of the CMS tracker with LHC and cosmic ray data
(2014)Journal of InstrumentationThe central component of the CMS detector is the largest silicon tracker ever built. The precise alignment of this complex device is a formidable challenge, and only achievable with a significant extension of the technologies routinely used for tracking detectors in the past. This article describes the full-scale alignment procedure as it is used during LHC operations. Among the specific features of the method are the simultaneous ...Journal Article -
Measurement of the production cross sections for a Z boson and one or more b jets in pp collisions at sqrt(s) = 7 TeV
(2014)Journal of High Energy PhysicsThe production of a Z boson, decaying into two leptons and produced in association with one or more b jets, is studied using proton-proton collisions delivered by the LHC at a centre-of-mass energy of 7 TeV. The data were recorded in 2011 with the CMS detector and correspond to an integrated luminosity of 5 fb−1. The Z(ℓℓ) + b-jets cross sections (where ℓℓ = μμ or ee) are measured separately for a Z boson produced with exactly one b jet ...Journal Article -
Measurement of the t-channel single-top-quark production cross section and of the |V tb| CKM matrix element in pp collisions at √s = 8 TeV
(2014)Journal of High Energy PhysicsMeasurements are presented of the t-channel single-top-quark production cross section in proton-proton collisions at s√ = 8 TeV. The results are based on a data sample corresponding to an integrated luminosity of 19.7 fb−1 recorded with the CMS detector at the LHC. The cross section is measured inclusively, as well as separately for top (t) and antitop (t¯), in final states with a muon or an electron. The measured inclusive t-channel cross ...Journal Article -
Measurement of the triple-differential cross section for photon + jets production in proton-proton collisions at √s = 7 TeV
(2014)Journal of High Energy PhysicsA measurement of the triple-differential cross section, d3σ/(dpγTdηγdηjet), in photon + jets final states using a data sample from proton-proton collisions at s√ = 7 TeV is presented. This sample corresponds to an integrated luminosity of 2.14 fb−1 collected by the CMS detector at the LHC. Photons and jets are reconstructed within a pseudorapidity range of |η| < 2.5, and are required to have transverse momenta in the range 40 < pjetT < ...Journal Article -
Search for new physics in the multijet and missing transverse momentum final state in proton-proton collisions at √s = 8 TeV
(2014)Journal of High Energy PhysicsA search for new physics is performed in multijet events with large missing transverse momentum produced in proton-proton collisions at s√ = 8 TeV using a data sample corresponding to an integrated luminosity of 19.5 fb−1 collected with the CMS detector at the LHC. The data sample is divided into three jet multiplicity categories (3-5, 6-7, and ≥8 jets), and studied further in bins of two variables: the scalar sum of jet transverse momenta ...Journal Article -
Search for pair production of excited top quarks in the lepton + jets final state
(2014)Journal of High Energy PhysicsA search is performed for pair-produced spin-3/2 excited top quarks (t∗t¯∗), each decaying to a top quark and a gluon. The search uses data collected with the CMS detector from pp collisions at a center-of-mass energy of s√ = 8 TeV, selecting events that have a single isolated muon or electron, an imbalance in transverse momentum, and at least six jets, of which one must be compatible with originating from the fragmentation of a b quark. ...Journal Article -
Measurement of Inclusive W and Z Boson Production Cross Sections in pp Collisions at √s =8 Te V
(2014)Physical Review LettersA measurement of total and fiducial inclusive W and Z boson production cross sections in pp collisions at √s=8 TeV is presented. Electron and muon final states are analyzed in a data sample collected with the CMS detector corresponding to an integrated luminosity of 18.2±0.5 pb−1. The measured total inclusive cross sections times branching fractions are σ(pp→WX)×B(W→ℓν)=12.21±0.03(stat)±0.24(syst)±0.32(lum) nb and σ(pp→ZX)×B(Z→ℓ+ℓ−)= ...Journal Article -
Measurement of the properties of a Higgs boson in the four-lepton final state
(2014)Physical Review DThe properties of a Higgs boson candidate are measured in the H→ZZ→4ℓ decay channel, with ℓ=e, μ, using data from pp collisions corresponding to an integrated luminosity of 5.1 fb−1 at the center-of-mass energy of √s=7 TeV and 19.7 fb−1 at √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, ...Journal Article -
Search for Flavor-Changing Neutral Currents in Top-Quark Decays t→Zq in pp Collisions at √s = 8 TeV
(2014)Physical Review LettersA search for flavor-changing neutral currents in top-quark decays t → Zq is performed in events produced from the decay chain t¯t → Zq + Wb, where both vector bosons decay leptonically, producing a final state with three leptons (electrons or muons). A data set collected with the CMS detector at the LHC is used, corresponding to an integrated luminosity of 19.7 fb−1 of proton-proton collisions at a center-of-mass energy of 8 TeV. No excess ...Journal Article -
Search for W´ → tb decays in the lepton + jets final state in pp collisions at √s = 8 TeV
(2014)Journal of High Energy PhysicsResults are presented from a search for the production of a heavy gauge boson W′ decaying into a top and a bottom quark, using a data set collected by the CMS experiment at s√ = 8 TeV and corresponding to an integrated luminosity of 19.5 fb−1. Various models of W′-boson production are studied by allowing for an arbitrary combination of left- and right-handed couplings. The analysis is based on the detection of events with a lepton (e, μ), ...Journal Article