29 research outputs found

    Search for Supersymmetry in pp Collisions at root s=13 TeV in the Single-Lepton Final State Using the Sum of Masses of Large-Radius Jets

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    Measurement of the B-+/- Meson Nuclear Modification Factor in Pb-Pb Collisions at root s(NN)=5.02 TeV

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    Measurements of the associated production of a Z boson and b jets in pp collisions at root s=8 TeV

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    Evidence for light-by-light scattering and searches for axion-like particles in ultraperipheral PbPb collisions at root s(NN)=5.02 TeV

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    Evidence for the light-by-light scattering process, gamma gamma -> gamma gamma, in ultraperipheral PbPb collisions at a centre-of-mass energy per nucleon pair of 5.02 TeV is reported. The analysis is conducted using a data sample corresponding to an integrated luminosity of 390 mu b(-1) recorded by the CMS experiment at the LHC. Light-by-light scattering processes are selected in events with two photons exclusively produced, each with transverse energy E-T(gamma) > 2 GeV, pseudorapidity vertical bar eta(gamma)vertical bar 5 GeV, diphoton transverse momentum p(T)(gamma gamma) gamma gamma) = 120 +/- 46(stat) +/- 28(syst) +/- 12(theo) nb, is consistent with the standard model prediction. The m(gamma gamma) distribution is used to set new exclusion limits on the production of pseudoscalar axion-like particles, via the gamma gamma -> a -> gamma gamma process, in the mass range m(a) = 5-90 GeV. (C) 2019 The Author(s). Published by Elsevier B.V.Peer reviewe

    Search for supersymmetry with photons in pp collisions at √s=8TeV

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    Two searches for physics beyond the standard model in events containing photons are presented. The data sample used corresponds to an integrated luminosity of 19.7  fb−1 of proton-proton collisions at √s=8  TeV, collected with the CMS experiment at the CERN LHC. The analyses pursue different inclusive search strategies. One analysis requires at least one photon, at least two jets, and a large amount of transverse momentum imbalance, while the other selects events with at least two photons and at least one jet, and uses the razor variables to search for signal events. The background expected from standard model processes is evaluated mainly from data. The results are interpreted in the context of general gauge-mediated supersymmetry, with the next-to-lightest supersymmetric particle either a bino- or wino-like neutralino, and within simplified model scenarios. Upper limits at the 95% confidence level are obtained for cross sections as functions of the masses of the intermediate supersymmetric particles

    Cross Section for b Jet Production in ppp\overline{p} Collisions at s\sqrt{s} = 1.8 TeV

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    Bottom quark production in pbar-p collisions at sqrt(s)=1.8 TeV is studied with 5 inverse picobarns of data collected in 1995 by the DO detector at the Fermilab Tevatron Collider. The differential production cross section for b jets in the central rapidity region (|y(b)| < 1) as a function of jet transverse energy is extracted from a muon-tagged jet sample. Within experimental and theoretical uncertainties, DO results are found to be higher than, but compatible with, next-to-leading-order QCD predictions. (arXiv

    Search for Higgs and Z boson decays to J/psi or Y pairs in the four-muon final state in proton-proton collisions at root s=13 TeV<bold> </bold>

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    A search for decays of the Higgs and Z boson to pairs of J/psi or Y(nS)(n = 1, 2, 3) mesons, with their subsequent decay to mu(+)mu(-) pairs, is presented. The analysis uses data from proton-proton collisions at root s = 13 TeV, collected with the CMS detector at the LHC in 2017 and corresponding to an integrated luminosity of 37.5 fb(-1). While an observation of such a decay with this sample would indicate the presence of physics beyond the standard model, no significant excess is observed. Upper limits at 95% confidence level are placed on the branching fractions of these decays. In the J/psi pair channel, the limits are 1.8 x 10(-3) and 2.2 x 10(-6) for the Higgs and Z boson, respectively, while in the combined Y(nS) pair channel, the limits are 1.4 x 10(-3) and 1.5 x 10(-6), respectively, when the mesons from the Higgs and Z boson decay are assumed to be unpolarized. When fully longitudinal and transverse polarizations are considered the limits reduce by about 22-29% and increase by about 10-13%, respectively. (C) 2019 The Author(s). Published by Elsevier B.V

    Combination of CMS searches for heavy resonances decaying to pairs of bosons or leptons

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    A statistical combination of searches for heavy resonances decaying to pairs of bosons or leptons is presented. The data correspond to an integrated luminosity of 35.9 fb(-1) collected during 2016 by the CMS experiment at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV. The data are found to be consistent with expectations from the standard model background. Exclusion limits are set in the context of models of spin-1 heavy vector triplets and of spin-2 bulk gravitons. For mass degenerate W' and Z' resonances that predominantly couple to the standard model gauge bosons, the mass exclusion at 95% confidence level of heavy vector bosons is extended to 4.5 TeV as compared to 3.8 TeV determined from the best individual channel. This excluded mass increases to 5.0 TeV if the resonances couple predominantly to fermions. (C) 2019 The Author(s). Published by Elsevier B.V

    Search for MSSM Higgs bosons decaying to <tex>\mu^{+}\mu^{-}</tex>inprotonprotoncollisionsat<tex>s</tex> in proton-proton collisions at <tex>\sqrt{s}</tex>=13TeV

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    Search for dark matter produced in association with heavy-flavor quark pairs in proton-proton collisions at s=13\sqrt{s}=13 TeV

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    International audienceA search is presented for an excess of events with heavy-flavor quark pairs ( tt{t}\overline{{t}} and bb{b} \overline{{b}} ) and a large imbalance in transverse momentum in data from proton–proton collisions at a center-of-mass energy of 13 TeV\,\text{TeV} . The data correspond to an integrated luminosity of 2.2 fb1\,\text{fb}^{-1} collected with the CMS detector at the CERN LHC. No deviations are observed with respect to standard model predictions. The results are used in the first interpretation of dark matter production in tt{t}\overline{{t}} and bb{b} \overline{{b}} final states in a simplified model. This analysis is also the first to perform a statistical combination of searches for dark matter produced with different heavy-flavor final states. The combination provides exclusions that are stronger than those achieved with individual heavy-flavor final states
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