Search
Results
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Evidence of b -Jet Quenching in PbPb Collisions at √sNN =2.76 TeV
(2014)Physical Review LettersThe production of jets associated to bottom quarks is measured for the first time in PbPb collisions at a center-of-mass energy of 2.76 TeV per nucleon pair. Jet spectra are reported in the transverse momentum (pT) range of 80-250GeV/c, and within pseudorapidity |η|<2. The nuclear modification factor (RAA) calculated from these spectra shows a strong suppression in the b-jet yield in PbPb collisions relative to the yield observed in pp ...Journal Article -
Measurement of top quark-antiquark pair production in association with a W or Z boson in pp collisions at √s=8 TeV
(2014)The European Physical Journal CA measurement of the cross section for the production of top quark–antiquark pairs (tt¯) in association with a vector boson V (W or Z) in proton-proton collisions at s√=8 TeV is presented. The results are based on a dataset corresponding to an integrated luminosity of 19.5 fb−1 recorded with the CMS detector at the LHC. The measurement is performed in three leptonic (e and μ) channels: a same-sign dilepton analysis targeting tt¯W events, ...Journal Article -
Search for the associated production of the Higgs boson with a top-quark pair
(2014)Journal of High Energy PhysicsA search for the standard model Higgs boson produced in association with a top-quark pair (tt¯H) is presented, using data samples corresponding to integrated luminosities of up to 5.1 fb−1 and 19.7 fb−1 collected in pp collisions at center-of-mass energies of 7 TeV and 8 TeV respectively. The search is based on the following signatures of the Higgs boson decay: H → hadrons, H → photons, and H → leptons. The results are characterized by ...Journal Article -
Measurement of prompt J/ψ pair production in pp collisions at √s = 7 Tev
(2014)Journal of High Energy PhysicsProduction of prompt J/ψ meson pairs in proton-proton collisions at s√ = 7 TeV is measured with the CMS experiment at the LHC in a data sample corresponding to an integrated luminosity of about 4.7 fb−1. The two J/ψ mesons are fully reconstructed via their decays into μ + μ − pairs. This observation provides for the first time access to the high-transverse-momentum region of J/ψ pair production where model predictions are not yet established. ...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 -
Measurement of WZ and ZZ production in pp collisions at √s = 8TeV in final states with b-tagged jets
(2014)The European Physical Journal CMeasurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at s√=8 TeV in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either W→eν, μν or Z→e+e−, μ+μ−, or νν¯¯¯). The results are based on data corresponding to an integrated luminosity of 18.9 fb−1 collected with the CMS detector at the Large Hadron Collider. The ...Journal Article -
Search for invisible decays of Higgs bosons in the vector boson fusion and associated ZH production modes
(2014)The European Physical Journal CA search for invisible decays of Higgs bosons is performed using the vector boson fusion and associated ZH production modes. In the ZH mode, the Z boson is required to decay to a pair of charged leptons or a bb¯¯¯ quark pair. The searches use the 8┬áTeV pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.7┬áfb−1. Certain channels include data from 7┬áTeV collisions corresponding ...Journal Article -
Measurement of jet multiplicity distributions in tt production in pp collisions at √s = 7TeV
(2014)The European Physical Journal CThe normalised differential top quark-antiquark production cross section is measured as a function of the jet multiplicity in proton-proton collisions at a centre-of-mass energy of 7TeV at the LHC with the CMS detector. The measurement is performed in both the dilepton and lepton+jets decay channels using data corresponding to an integrated luminosity of 5.0fb−1. Using a procedure to associate jets to decay products of the top quarks, the ...Journal Article -
Evidence for the direct decay of the 125 GeV Higgs boson to fermions
(2014)Nature PhysicsThe discovery of a new boson with a mass of approximately 125 GeV in 2012 at the Large Hadron Collider1,2,3 has heralded a new era in understanding the nature of electroweak symmetry breaking and possibly completing the standard model of particle physics4,5,6,7,8,9. Since the first observation in decays to γγ, WW and ZZ boson pairs, an extensive set of measurements of the mass10,11 and couplings to W and Z bosons11,12,13, as well as ...Journal Article -
Search for massive resonances in dijet systems containing jets tagged as W or Z boson decays in pp collisions at √s = 8 TeV
(2014)Journal of High Energy PhysicsA search is reported for massive resonances decaying into a quark and a vector boson (W or Z), or two vector bosons (WW, WZ, or ZZ). The analysis is performed on an inclusive sample of multijet events corresponding to an integrated luminosity of 19.7 fb−1, collected in proton-proton collisions at a centre-of-mass energy of 8 TeV with the CMS detector at the LHC. The search uses novel jet-substructure identification techniques that provide ...Journal Article