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Measurement of the tt¯ production cross section in pp collisions at √s=8 TeV in dilepton final states containing one τ lepton
(2014)Physics Letters BThe top-quark pair production cross section is measured in final states with one electron or muon and one hadronically decaying τ lepton from the process tt→(ℓνℓ)(τντ)bb-, where ℓ=e,μ. The data sample corresponds to an integrated luminosity of 19.6 fb-1 collected with the CMS detector in proton-proton collisions at √s=8 TeV. The measured cross section σtt-=257±3 (stat)±24 (syst)±7 (lumi) pb, assuming a top-quark mass of 172.5 GeV, is ...Journal Article -
NA61/SHINE facility at the CERN SPS: beams and detector system
(2014)Journal of InstrumentationNA61/SHINE (SPS Heavy Ion and Neutrino Experiment) is a multi-purpose experimental facility to study hadron production in hadron-proton, hadron-nucleus and nucleus-nucleus collisions at the CERN Super Proton Synchrotron. It recorded the first physics data with hadron beams in 2009 and with ion beams (secondary 7Be beams) in 2011. NA61/SHINE has greatly profited from the long development of the CERN proton and ion sources and the ...Journal Article -
Search for anomalous production of events with three or more leptons in pp collisions at √s = 8 TeV
(2014)Physical Review DA search for physics beyond the standard model in events with at least three leptons is presented. The data sample, corresponding to an integrated luminosity of 19.5 fb−1 of proton-proton collisions with center-of-mass energy √s = 8 TeV, was collected by the CMS experiment at the LHC during 2012. The data are divided into exclusive categories based on the number of leptons and their flavor, the presence or absence of an opposite-sign, ...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 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 -
Online coupled regional meteorology chemistry models in Europe: current status and prospects
(2014)Atmospheric Chemistry and PhysicsOnline coupled mesoscale meteorology atmospheric chemistry models have undergone a rapid evolution in recent years. Although mainly developed by the air quality modelling community, these models are also of interest for numerical weather prediction and regional climate modelling as they can consider not only the effects of meteorology on air quality, but also the potentially important effects of atmospheric composition on weather. Two ...Journal Article -
Measurement of the ratio B(t→Wb)/B(t→Wq) in pp collisions at √s = 8 TeV
(2014)Physics Letters BThe ratio of the top-quark branching fractions R = B(t --> Wb)/B(t --> Wq), where the denominator includes the sum over all down-type quarks (q = b, s, d), is measured in the t (t) over bar dilepton final state with proton-proton collision data at root s = 8 TeV from an integrated luminosity of 19.7 fb(-1), collected with the CMS detector. In order to quantify the purity of the signal sample, the cross section is measured by fitting the ...Journal Article -
Observation of a peaking structure in the J/ψφ mass spectrum from B±→J/ψφK± decays
(2014)Physics Letters BA peaking structure in the J/ψφ mass spectrum near threshold is observed in B ±→J/ψφK± decays, produced in pp collisions at √s=7 TeV collected with the CMS detector at the LHC. The data sample, selected on the basis of the dimuon decay mode of the J/ψ, corresponds to an integrated luminosity of 5.2 fb-1. Fitting the structure to an S-wave relativistic Breit-Wigner lineshape above a three-body phase-space nonresonant component gives a ...Journal Article -
Measurement of the production cross section for a W boson and two b jets in pp collisions at √s=7 TeV
(2014)Physics Letters BThe production cross section for a W boson and two b jets is measured using proton-proton collisions at √s=7 TeV in a data sample collected with the CMS experiment at the LHC corresponding to an integrated luminosity of 5.0 fb-1. The W+bb- events are selected in the W→μν decay mode by requiring a muon with transverse momentum pT > 25 GeV and pseudorapidity |η| < 2.1, and exactly two b-tagged jets with pT > 25 GeV and |η| < 2.4. The measured ...Journal Article -
Search for pair production of third-generation scalar leptoquarks and top squarks in proton-proton collisions at √s = 8 TeV
(2014)Physics Letters BA search for pair production of third-generation scalar leptoquarks and supersymmetric top quark partners, top squarks, in final states involving tau leptons and bottom quarks is presented. The search uses events from a data sample of proton–proton collisions corresponding to an integrated luminosity of 19.7 fb−1, collected with the CMS detector at the LHC with s=8 TeV. The number of observed events is found to be in agreement with the ...Journal Article