Publications by authors named "Dhondt J"

This paper presents a measurement of the inclusive 3-jet production differential cross section at a proton-proton centre-of-mass energy of 7 TeV using data corresponding to an integrated luminosity of 5[Formula: see text]collected with the CMS detector. The analysis is based on the three jets with the highest transverse momenta. The cross section is measured as a function of the invariant mass of the three jets in a range of 445-3270 GeV and in two bins of the maximum rapidity of the jets up to a value of 2.

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A search has been performed for long-lived particles that could have come to rest within the CMS detector, using the time intervals between LHC beam crossings. The existence of such particles could be deduced from observation of their decays via energy deposits in the CMS calorimeter appearing at times that are well separated from any proton-proton collisions. Using a data set corresponding to an integrated luminosity of 18.

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The purely electroweak (EW) cross section for the production of two jets in association with a Z boson, in proton-proton collisions at [Formula: see text], is measured using data recorded by the CMS experiment at the CERN LHC, corresponding to an integrated luminosity of 19.7[Formula: see text]. The electroweak cross section for the [Formula: see text] final state (with [Formula: see text] or [Formula: see text] and j representing the quarks produced in the hard interaction) in the kinematic region defined by [Formula: see text][Formula: see text], [Formula: see text][Formula: see text], transverse momentum [Formula: see text][Formula: see text], and pseudorapidity [Formula: see text], is found to be [Formula: see text], in agreement with the standard model prediction.

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Results are presented from a search for new decaying massive particles whose presence is inferred from an imbalance in transverse momentum and which are produced in association with a single top quark that decays into a bottom quark and two light quarks. The measurement is performed using 19.7  fb^{-1} of data from proton-proton collisions at a center-of-mass energy of 8 TeV, collected with the CMS detector at the CERN LHC.

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A search for new long-lived particles decaying to leptons is presented using proton-proton collisions produced by the LHC at √[s]=8  TeV. Data used for the analysis were collected by the CMS detector and correspond to an integrated luminosity of 19.7  fb(-1).

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A study of vector boson scattering in pp collisions at a center-of-mass energy of 8 TeV is presented. The data sample corresponds to an integrated luminosity of 19.4  fb(-1) collected with the CMS detector.

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The ratio between the prompt ψ(2S) and J/ψ yields, reconstructed via their decays into μ+ μ-, is measured in Pb-Pb and p-p collisions at sqrt[sNN]=2.76  TeV. The analysis is based on Pb-Pb and p-p data samples collected by CMS at the Large Hadron Collider, corresponding to integrated luminosities of 150  μb(-1) and 5.

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The 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 (p(T)) range of 80-250  GeV/c, and within pseudorapidity |η|<2.

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Results are presented from a search for the rare decays Bs(0)→μ+ μ- and B(0)→μ+ μ- in pp collisions at sqrt[s]=7 and 8 TeV, with data samples corresponding to integrated luminosities of 5 and 20  fb(-1), respectively, collected by the CMS experiment at the LHC. An unbinned maximum-likelihood fit to the dimuon invariant mass distribution gives a branching fraction B(Bs(0)→μ+ μ-)=(3.0(-0.

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The first observation of the associated production of a single top quark and a W boson is presented. The analysis is based on a data set corresponding to an integrated luminosity of 12.2 fb(-1) of proton-proton collisions at sqrt[s] = 8 TeV recorded by the CMS experiment at the LHC.

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Article Synopsis
  • A study was conducted measuring the production rates of W and Z bosons in proton-proton collisions at a collision energy of 8 TeV, using data from the CMS detector.
  • The results indicated a total inclusive cross-section for W bosons of 12.21 nb and for Z bosons of 1.15 nb, with small associated uncertainties.
  • These findings are consistent with advanced theoretical predictions and represent the first measurement of these bosons at this energy level in such collisions.
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Spin correlations and polarization in the top quark-antiquark system are measured using dilepton final states produced in pp collisions at the LHC at sqrt[s]=7  TeV. The data correspond to an integrated luminosity of 5.0  fb(-1) collected with the CMS detector.

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Article Synopsis
  • * Data was collected using the CMS detector at the LHC, involving 19.7 fb(-1) of proton-proton collisions at 8 TeV.
  • * The results show no excess events compared to standard model predictions, indicating no evidence for flavor-changing neutral currents, and a branching fraction greater than 0.05% is excluded at a 95% confidence level.
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  • A search was conducted for heavy partners of the top quark with a charge of 5/3, using data from the CMS experiment which had an integrated luminosity of 19.5 fb(-1) at a collision energy of 8 TeV.
  • No significant excess above the anticipated background was found, leading to the exclusion of top-quark partners with masses under 800 GeV at a 95% confidence level, assuming these partners decay only to tW.
  • This study provides the first limit on such particles from the Large Hadron Collider (LHC) and offers a stricter constraint compared to previous findings.
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Results are presented of a search for a "natural" supersymmetry scenario with gauge mediated symmetry breaking. It is assumed that only the supersymmetric partners of the top quark (the top squark) and the Higgs boson (Higgsino) are accessible. Events are examined in which there are two photons forming a Higgs boson candidate, and at least two b-quark jets.

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A measurement of the cross section for the production of top quark-antiquark pairs ([Formula: see text]) in association with a vector boson V (W or Z) in proton-proton collisions at [Formula: see text][Formula: see text] is presented. The results are based on a dataset corresponding to an integrated luminosity of 19.5 fb[Formula: see text] recorded with the CMS detector at the LHC.

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Searches for the direct electroweak production of supersymmetric charginos, neutralinos, and sleptons in a variety of signatures with leptons and [Formula: see text], [Formula: see text], and Higgs bosons are presented. Results are based on a sample of proton-proton collision data collected at center-of-mass energy [Formula: see text] with the CMS detector in 2012, corresponding to an integrated luminosity of 19.5 [Formula: see text].

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Article Synopsis
  • The study measures the production cross section of top quark-antiquark pairs in proton-proton collisions at the LHC, specifically looking at how this varies with the number of jets produced.
  • It utilizes data from both dilepton and lepton+jets decay channels, analyzing events with an integrated luminosity of 5.0 fb⁻¹.
  • Results indicate that the observed data aligns well with predictions made by quantum chromodynamics, showing no significant discrepancies.
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A 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 [Formula: see text] quark pair. The searches use the 8 [Formula: see text] pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.

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Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at [Formula: see text][Formula: see text] 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 [Formula: see text], [Formula: see text] or [Formula: see text], [Formula: see text], or [Formula: see text]). The results are based on data corresponding to an integrated luminosity of 18.

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A study of color coherence effects in pp collisions at a center-of-mass energy of 7[Formula: see text] is presented. The data used in the analysis were collected in 2010 with the CMS detector at the LHC and correspond to an integrated luminosity of 36 pb[Formula: see text]. Events are selected that contain at least three jets and where the two jets with the largest transverse momentum exhibit a back-to-back topology.

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Spectra of identified charged hadrons are measured in pPb collisions with the CMS detector at the LHC at [Formula: see text]. Charged pions, kaons, and protons in the transverse-momentum range [Formula: see text]-1.7[Formula: see text] and laboratory rapidity [Formula: see text] are identified via their energy loss in the silicon tracker.

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Article Synopsis
  • - The mass of the top quark is determined using data from candidate events featuring at least six jets, collected by the CMS detector during proton-proton collisions at [Formula: see text] TeV in 2011, totaling an integrated luminosity of 3.54 [Formula: see text].
  • - Each event undergoes a kinematic fit of the jets to a [Formula: see text] hypothesis to accurately reconstruct the mass.
  • - The final measurement for the top-quark mass is reported as [Formula: see text] GeV, which is further refined by combining it with earlier measurements from different decay modes by CMS, resulting in a combined mass of [Formula: see text] GeV.
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  • The CMS experiment conducted a search for heavy right-handed neutrinos and right-handed [Formula: see text] bosons, which are part of theoretical extensions of the standard model of particle physics.
  • This search utilized data from proton-proton collisions at 8[Formula: see text] with an integrated luminosity of 19.7 [Formula: see text], focusing on two lepton plus two jet events.
  • The findings showed that the excluded mass region for these particles at a 95% confidence level is significantly larger than previous studies, especially in the range of neutrino masses below the [Formula: see text] boson mass.
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  • * A data-driven isolation template method was employed to accurately determine the prompt diphoton yield, specifically focusing on photons with transverse energies above certain thresholds.
  • * The results, including cross sections as a function of various parameters, are compared against theoretical predictions from quantum chromodynamics (QCD) at different order levels to assess their alignment with experimental data.
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