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Search for Top-Quark Partners with Charge 5/3 in the Same-Sign Dilepton Final State
(2014)Physical Review LettersA search for the production of heavy partners of the top quark with charge 5/3 is performed in events with a pair of same-sign leptons. The data sample corresponds to an integrated luminosity of 19.5fb−1 and was collected at √s = 8 TeV by the CMS experiment. No significant excess is observed in the data above the expected background, and the existence of top-quark partners with masses below 800 GeV is excluded at a 95% confidence level, ...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 -
Measurement of four-jet production in proton-proton collisions at √s =7TeV
(2014)Physical Review DMeasurements of the differential cross sections for the production of exactly four jets in proton-proton collisions are presented as a function of the transverse momentum pT and pseudorapidity η, together with the correlations in azimuthal angle and the pT balance among the jets. The data sample was collected in 2010 at a center-of-mass energy of 7 TeV with the CMS detector at the LHC, with an integrated luminosity of 36 pb−1. The cross ...Journal Article -
Measurements of t¯t Spin Correlations and Top-Quark Polarization Using Dilepton Final States in pp Collisions at √s=7 TeV
(2014)Physical Review LettersSpin correlations and polarization in the top quark–antiquark system are measured using dilepton final states produced in pp collisions at the LHC at √s=7 TeV. The data correspond to an integrated luminosity of 5.0 fb−1 collected with the CMS detector. The measurements are performed using events with two oppositely charged leptons (electrons or muons), a significant imbalance in transverse momentum, and two or more jets, where at least ...Journal Article -
Search for baryon number violation in top-quark decays
(2014)Physics Letters BA search for baryon number violation (BNV) in top-quark decays is performed using pp collisions produced by the LHC at s=8 TeV. The top-quark decay considered in this search results in one light lepton (muon or electron), two jets, but no neutrino in the final state. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.5 fb-1. The event selection is optimized for top quarks produced ...Journal Article -
Measurement of the top-quark mass in all-jets tt events in pp collisions at √s = 7 TeV
(2014)The European Physical Journal CThe mass of the top quark is measured using a sample of tt¯ candidate events with at least six jets in the final state. The sample is selected from data collected with the CMS detector in pp collisions at s√=7 TeV in 2011 and corresponds to an integrated luminosity of 3.54 fb−1. The mass is reconstructed for each event employing a kinematic fit of the jets to a tt¯ hypothesis. The top-quark mass is measured to be 173.49±0.69(stat.)±1.21(syst.) ...Journal Article -
Measurement of higher-order harmonic azimuthal anisotropy in PbPb collisions at √sNN=2.76 TeV
(2014)Physical Review CMeasurements are presented by the CMS Collaboration at the Large Hadron Collider (LHC) of the higher-order harmonic coefficients that describe the azimuthal anisotropy of charged particles emitted in √sNN=2.76 TeV PbPb collisions. Expressed in terms of the Fourier components of the azimuthal distribution, the n=3–6 harmonic coefficients are presented for charged particles as a function of their transverse momentum (0.3<pT<8.0GeV/c), ...Journal Article -
Measurements of the t¯t charge asymmetry using the dilepton decay channel in pp collisions at √s = 7 TeV
(2014)Journal of High Energy PhysicsThe tt¯ charge asymmetry in proton-proton collisions at s√ = 7 TeV is measured using the dilepton decay channel (ee, eμ, or μμ). The data correspond to a total integrated luminosity of 5.0 fb−1, collected by the CMS experiment at the LHC. The tt and lepton charge asymmetries, defined as the differences in absolute values of the rapidities between the reconstructed top quarks and antiquarks and of the pseudorapidities between the positive ...Journal Article -
Event activity dependence of Y(nS) production in √sNN =5.02 TeV pPb and √s=2.76 TeV pp collisions
(2014)Journal of High Energy PhysicsThe production of Y(1S), Y(2S), and Y(3S) is investigated in pPb and pp collisions at centre-of-mass energies per nucleon pair of 5.02 TeV and 2.76 TeV, respectively. The datasets correspond to integrated luminosities of about 31 nb−1 (pPb) and 5.4 pb−1 (pp), collected in 2013 by the CMS experiment at the LHC. Upsilons that decay into muons are reconstructed within the rapidity interval |y CM| < 1.93 in the nucleon-nucleon centre-of-mass ...Journal Article -
Modification of jet shapes in PbPb collisions at sNN=2.76TeV
(2014)Physics Letters BThe first measurement of jet shapes, defined as the fractional transverse momentum radial distribution, for inclusive jets produced in heavy-ion collisions is presented. Data samples of PbPb and pp collisions, corresponding to integrated luminosities of 150 mu b(-1) and 5.3 pb(-1) respectively, were collected at a nucleon-nucleon centre-of-mass energy of root s(NN) = 2.76 TeV with the CMS detector at the LHC. The jets are reconstructed ...Journal Article