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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 -
Search for a W′ or Techni-ρ Decaying into WZ in pp Collisions at √s=7 TeV
(2012)Physical Review LettersA search is performed in pp collisions at √s=7 TeV for exotic particles decaying via WZ to final states with electrons and muons. The data sample corresponds to an integrated luminosity of approximately 5 fb−1. No significant excess is observed in the data above the expected standard model background. Upper bounds at 95% confidence level are set on the production cross section of the W′ boson described by the sequential standard model ...Journal Article -
Measurement of jet fragmentation into charged particles in pp and PbPb collisions at √sNN=2.76 TeV
(2012)Journal of High Energy PhysicsJet fragmentation in pp and PbPb collisions at a centre-of-mass energy of 2.76 TeV per nucleon pair was studied using data collected with the CMS detector at the LHC. Fragmentation functions are constructed using charged-particle tracks with transverse momenta p T > 4 GeV/c for dijet events with a leading jet of p T > 100 GeV/c. The fragmentation functions in PbPb events are compared to those in pp data as a function of collision centrality, ...Journal Article -
Search for New Physics in the Multijet and Missing Transverse Momentum Final State in Proton-Proton Collisions at √s=7 TeV
(2012)Physical Review LettersA search for physics beyond the standard model is performed in events with at least three jets and large missing transverse momentum produced in proton-proton collisions at a center-of-mass energy of √s=7 TeV. No significant excess of events above the expected backgrounds is observed in 4.98 fb−1 of data collected with the CMS detector at the Large Hadron Collider. The results are presented in the context of the constrained minimal ...Journal Article