Search
Results
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Combined search for the quarks of a sequential fourth generation
(2012)Physical Review DResults are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 fb−1 recorded by the CMS experiment at the LHC in 2011. A novel strategy has been developed for a combined search for quarks of the up and down type in decay channels with at least one isolated muon or electron. Limits on the mass of the fourth-generation quarks and the relevant ...Journal Article -
Observation of Z decays to four leptons with the CMS detector at the LHC
(2012)Journal of High Energy PhysicsThe first observation of the Z boson decaying to four leptons in proton-proton collisions is presented. The analyzed data set corresponds to an integrated luminosity of 5.02 fb−1 at s√=7 TeV collected by the CMS detector at the Large Hadron Collider. A pronounced resonance peak, with a statistical significance of 9.7 σ, is observed in the distribution of the invariant mass of four leptons (electrons and/or muons) with mass and width ...Journal Article -
Search for third-generation leptoquarks and scalar bottom quarks in pp collisions at √s=7TeV
(2012)Journal of High Energy PhysicsResults are presented from a search for third-generation leptoquarks and scalar bottom quarks in a sample of proton-proton collisions at s√=7TeV collected by the CMS experiment at the LHC, corresponding to an integrated luminosity of 4.7 fb−1. A scenario where the new particles are pair produced and each decays to a b quark plus a tau neutrino or neutralino is considered. The number of observed events is found to be in agreement with the ...Journal Article -
Measurement of the single-top-quark t-channel cross section in pp collisions at root s=7 TeV
(2012)Journal of High Energy PhysicsA measurement of the single-top-quark t-channel production cross section in pp collisions at s√=7 TeV with the CMS detector at the LHC is presented. Two different and complementary approaches have been followed. The first approach exploits the distributions of the pseudorapidity of the recoil jet and reconstructed top-quark mass using background estimates determined from control samples in data. The second approach is based on multivariate ...Journal Article -
Search for resonant t(t)over-bar production in lepton plus jets events in pp collisions at s √ =7 TeV
(2012)Journal of High Energy PhysicsA model-independent search for the production of heavy resonances decaying into top-antitop quark pairs is presented. The search is based on events containing one lepton (muon or electron) and at least two jets selected from data samples corresponding to an integrated luminosity of 4.4-5.0 fb−1 collected in pp collisions at s√=7 TeV. Results are presented from the combination of two dedicated searches optimized for boosted production and ...Journal Article -
Measurement of the top-quark mass in tt − events with lepton+jets final states in pp collisions at √s =7 TeV
(2012)Journal of High Energy PhysicsThe mass of the top quark is measured using a sample of tt¯ candidate events with one electron or muon and at least four jets in the final state, collected by CMS in pp collisions at s√=7 TeV at the LHC. A total of 5174 candidate events is selected from data corresponding to an integrated luminosity of 5.0 fb−1. For each event the mass is reconstructed from a kinematic fit of the decay products to a tt¯ hypothesis. The top-quark mass is ...Journal Article -
Observation of Sequential gamma Suppression in PbPb Collisions
(2012)Physical Review LettersThe suppression of the individual Υ(nS) states in PbPb collisions with respect to their yields in pp data has been measured. The PbPb and pp data sets used in the analysis correspond to integrated luminosities of 150 μb−1 and 230 nb−1, respectively, collected in 2011 by the CMS experiment at the LHC, at a center-of-mass energy per nucleon pair of 2.76 TeV. The Υ(nS) yields are measured from the dimuon invariant mass spectra. The suppression ...Journal Article -
A search for a doubly-charged Higgs boson in pp collisions at √s=7 TeV
(2012)The European Physical Journal CA search for a doubly-charged Higgs boson in pp collisions at s√=7 TeV is presented. The data correspond to an integrated luminosity of 4.9 fb−1, collected by the CMS experiment at the LHC. The search is performed using events with three or more isolated charged leptons of any flavor, giving sensitivity to the decays of pair-produced triplet components Φ ++ Φ −−, and Φ ++ Φ − from associated production. No excess is observed compared to ...Journal Article -
Ratios of dijet production cross sections as a function of the absolute difference in rapidity between jets in proton–proton collisions at √s=7 TeV
(2012)The European Physical Journal CA study of dijet production in proton–proton collisions was performed at s√=7~TeV for jets with p T>35 GeV and |y|<4.7 using data collected with the CMS detector at the LHC in 2010. Events with at least one pair of jets are denoted as “inclusive”. Events with exactly one pair of jets are called “exclusive”. The ratio of the cross section of all pairwise combinations of jets to the exclusive dijet cross section as a function of the rapidity ...Journal Article -
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