SEARCH · Engineering Papers
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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We study a model with partial quark-lepton universality that can naturally arise in grand unified theories. We find that constraints on the model can be reduced to a single condition on the Dirac CP phase δ in the neutrino sector. Using our current knowledge of the CKM and PMNS mixing matrices, we predict - 32 . 4 ° ≤ δ ≤ 32 . 0 ° at 2 σ .
CERN-LHC. Results from a search for supersymmetry in events with four or more leptons including electrons, muons and taus are presented. The analysis uses a data sample corresponding to 20.3 fb^{-1} of proton-proton collisions delivered by the Large Hadron Collider at sqrt(s) = 8 TeV and recorded by the ATLAS detector. Signal regions are designed to target supersymmetric scenarios that can be either enriched in or depleted of events involving the production of a Z boson. No significant deviations are observed in data from Standard Model predictions and results are used to set upper limits on the event yields from processes beyond the Standard Model. Exclusion limits at the 95% confidence level on the masses of relevant supersymmetric particles are obtained. In R-parity-violating simplified models with decays of the lightest supersymmetric particle to electrons and muons, limits of 1350 GeV and 750 GeV are placed on gluino and chargino masses, respectively. In R-parity-conserving simplified models with heavy neutralinos decaying to a massless lightest supersymmetric particle, heavy neutralino masses up to 620 GeV are excluded. Limits are also placed on other supersymmetric scenarios.
CERN-LHC. A generic search for anomalous production of events with at least three charged leptons is presented.
CERN-LHC. The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider (LHC) are reported.
CERN-LHC. The results of a search for top squark (stop) pair production in final states with one isolated lepton, jets, and missing transverse momentum are reported.
CERN-LHC. A search is presented for a narrow diboson resonances decaying to WW or WZ in the final state where one W boson decays leptonically (to an electron or a muon plus a neutrino) and the other W/Z boson decays hadronically.
CERN-LHC. Many extensions of the Standard Model posit the existence of heavy particles with long lifetimes. This article presents the results of a search for events containing at least one long-lived particle that decays at a significant distance from its production point into two leptons or into five or more charged particles.
CERN-LHC. The results of a search for vector-like top quarks using events with exactly one lepton, at least four jets, and large missing transverse momentum are reported.
CERN-LHC, ATLAS. Limits on pair production of a heavy vector-like T quark together with its antiparticle, where the T quark decays to a W boson and a b quark. The search is based on 36.1 +\- 1.2 fb^{-1} of pp collisions at sqrt{s} = 13 TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Data are analysed in the lepton plus jets final state, including at least one b-tagged jet and a large-radius jet identified as originating from the hadronic decay of a high-momentum W boson. The search is also sensitive to a heavy vector-like B quark, in particular in the decay to Wt and the results are thus reinterpreted to provide limits on the B mass. Mass limits on both T and B production are also set as a function of the decay branching ratios.
CERN-LHC. Search for a new heavy gauge-boson resonance decaying into a lepton and missing transverse momentum in 36/fb of pp collisions at sqrt{s} = 13 TeV with the ATLAS experiment
CERN-LHC. A search for new phenomena in final states characterized by high jet multiplicity, an isolated lepton (electron or muon) and either zero or at least three b-tagged jets is presented. The search uses 36.1 fb-1 of sqrt(s) = 13 TeV proton-proton collision data collected by the ATLAS experiment at the Large Hadron Collider in 2015 and 2016. The dominant sources of background are estimated using parameterized extrapolations, based on observables at medium jet multiplicity, to predict the b-tagged jet multiplicity distribution at the higher jet multiplicities used in the search. No significant excess over the Standard Model expectation is observed and 95% confidence-level limits are extracted constraining four simplified models of R-parity-violating supersymmetry that feature either gluino or top-squark pair production. The exclusion limits reach as high as 2.1 TeV in gluino mass and 1.2 TeV in top-squark mass in the models considered. In addition, an upper limit is set on the cross-section for Standard Model tttt production of 60 fb (6.5 times the Standard Model prediction) at 95% confidence level. Finally, model-independent limits are set on the contribution from new phenomena to the signal-region yields.
CERN-LHC. Measurements of the absolute and fiducial differential cross-sections for single leptons and the dilepton system in ttbar production at sqrt(s)=8 TeV, decaying to the e-mu bbbar nnubar final state.
CERN-ATLAS. Search for heavy resonances decaying into a W or Z boson and a Higgs boson in final states with leptons and b-jets in 36 1/fb of 13 TeV pp collisions with the ATLAS detector
A search for doubly-charged Higgs bosons with pairs of prompt, isolated, highly energetic leptons with the same electric charge is presented.
CERN-LHC, ATLAS HEP data for the Search for resonant W Z Production in the fully leptonic final state in Proton-Proton Collisions at sqrt(s) = 13 TeV with the ATLAS Detector.
Results from a search for supersymmetry in events with four or more charged leptons (electrons, muons and taus) are presented.
CERN-LHC, ATLAS. Limits on pair production of a heavy vector-like B quark together with its antiparticle, where the B quark decays to a W boson and a top quark. The search is based on 36.1 +\- 0.8 fb^{-1} of pp collisions at sqrt{s} = 13 TeV recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Data are analysed in the lepton plus jets final state, including at least four small jets out of which at least one is required to be b-tagged jet and a large-radius jet. Mass limits on B production are set as a function of the decay branching ratios.
A measurement of total production cross sections of the Higgs boson in proton-proton collisions is presented in the H -> tau tau decay channel. The analysis is performed using 36.1 fb-1 of data recorded by the ATLAS experiment at the Large Hadron Collider at a center-of-mass energy of 13 TeV. All combinations of leptonic and hadronic tau decays are considered. The H->tau tau signal over the expected background from other Standard Model processes is established with an observed (expected) significance of 4.4 (4.1) standard deviations. Combined with results using data taken at 7 and 8 TeV centre-of-mass energies, the observed (expected) significance amounts to 6.4 (5.4) standard deviations and constitutes an observation of H->tautau decays by the ATLAS experiment.