Search
Results
-
Measurement of the tt¯ production cross section in the dilepton channel in pp collisions at √s=7 TeV
(2012)Journal of High Energy PhysicsThe tt¯ production cross section (σtt¯) is measured in proton-proton collisions at s√=7 TeV in data collected by the CMS experiment, corresponding to an integrated luminosity of 2.3 fb−1. The measurement is performed in events with two leptons (electrons or muons) in the final state, at least two jets identified as jets originating from b quarks, and the presence of an imbalance in transverse momentum. The measured value of σtt¯ for a ...Journal Article -
Search for exclusive or semi-exclusive photon pair production and observation of exclusive and semi-exclusive electron pair production in pp collisions at √s=7 TeV
(2012)Journal of High Energy PhysicsA search for exclusive or semi-exclusive γγ production, pp → p(*) + γγ + p(*) (where p* stands for a diffractively-dissociated proton), and the observation of exclusive and semi-exclusive e+e− production, pp → p(*) + e+e− + p(*), in proton-proton collisions at s√=7 TeV, are presented. The analysis is based on a data sample corresponding to an integrated luminosity of 36 pb−1 recorded by the CMS experiment at the LHC at low instantaneous ...Journal Article -
Search for electroweak production of charginos and neutralinos using leptonic final states in pp collisions at √s=7 TeV
(2012)Journal of High Energy PhysicsThe 2011 dataset of the CMS experiment, consisting of an integrated luminosity of 4.98 fb−1 of pp collisions at s√=7 TeV, enables expanded searches for direct electroweak pair production of charginos and neutralinos in supersymmetric models as well as their analogs in other models of new physics. Searches sensitive to such processes, with decays to final states that contain two or more leptons, are presented. Final states with three ...Journal Article -
Search for new physics with long-lived particles decaying to photons and missing energy in pp collisions at √s=7 TeV
(2012)Journal of High Energy PhysicsA search is performed for long-lived neutral particles decaying into a photon and invisible particles. An example of such a signature is the decay of the lightest neutralino with nonzero lifetime into a gravitino and a photon in gauge-mediated supersymmetry, with the neutralino as the next-to-lightest supersymmetric particle and the gravitino as the lightest. The search uses events containing photons, missing transverse energy, and jets. ...Journal Article -
Search for charge-asymmetric production of W′ bosons in top pair + jet events from pp collisions at √s = 7 TeV
(2012)Physics Letters BA search is presented for charge-asymmetric production of a W' boson that has been proposed to accommodate the forward-backward asymmetry observed in the production of top-antitop quark pairs at the Tevatron. The new heavy W' boson would be produced in association with a top quark and would decay into top and down quarks. The data correspond to an integrated luminosity of 5.0 fb(-1) in pp collisions at a center-of-mass energy of 7 TeV, ...Journal Article -
Study of the inclusive production of charged pions, kaons, and protons in pp collisions at √s=0.9, 2.76, and 7 TeV
(2012)The European Physical Journal CSpectra of identified charged hadrons are measured in pp collisions at the LHC for s√=0.9,2.76, and 7 TeV. Charged pions, kaons, and protons in the transverse-momentum range p T≈0.1–1.7 GeV/c and for rapidities |y|<1 are identified via their energy loss in the CMS silicon tracker. The average p T increases rapidly with the mass of the hadron and the event charged-particle multiplicity, independently of the center-of-mass energy. The fully ...Journal Article -
Search for heavy Majorana neutrinos in μ±μ±+jets and e±e±+jets events in pp collisions at √s =7 TeV
(2012)Physics Letters BA search for excited leptons is carried out with the CMS detector at the LHC, using 36 pb-1 of pp collision data recorded at s=7 TeV. The search is performed for associated production of a lepton and an oppositely charged excited lepton pp→ℓℓ*, followed by the decay ℓ*→ℓγ, resulting in the ℓℓγ final state, where ℓ=e,μ. No excess of events above the standard model expectation is observed. Interpreting the findings in the context of ℓ* ...Journal Article -
Inclusive and differential measurements of the ttˉ charge asymmetry in proton–proton collisions at 7 TeV
(2012)Physics Letters BThe tt- charge asymmetry is measured in events containing a charged lepton (electron or muon) and at least four jets, one of which is identified as originating from b-quark hadronization. The analyzed dataset corresponds to an integrated luminosity of 5.0 fb -1 collected with the CMS detector at the LHC. An inclusive and three differential measurements of the tt- charge asymmetry as a function of rapidity, transverse momentum, and invariant ...Journal Article -
Measurement of the top-quark mass in tt events with dilepton final states in pp collisions at s√ =7 TeV
(2012)The European Physical Journal CThe top-quark mass is measured in proton-proton collisions at s√=7 TeV using a data sample corresponding to an integrated luminosity of 5.0 fb−1 collected by the CMS experiment at the LHC. The measurement is performed in the dilepton decay channel tt¯→(ℓ+νℓb)(ℓ−ν¯¯¯ℓb¯¯¯), where ℓ=e,μ. Candidate top-quark decays are selected by requiring two leptons, at least two jets, and imbalance in transverse momentum. The mass is reconstructed with ...Journal Article -
Performance of CMS muon reconstruction in pp collision events at √s = 7 TeV
(2012)Journal of InstrumentationThe performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 pb−1 of data collected in pp collisions at √s = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV/c is above 95% over ...Journal Article