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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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At least 253 records · Page 14
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

100 TeV pp collisions, Higgs type, PYTHIA6 generator: tev100pp_pythia6_higgs_zz_4l

Higgs production to ZZ* in Pythia6.4. Z-boson decays to e+e- or mu+mu-. This sample uses older Pythia version for detector performance studies and creation of full simulated samples. No slimming. The sample is not recommended for physics studies since uses outdated PDF built-in in Pythai6.4 1k events per file. The full simulation is based on SiD detector to check performance issues.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for anomalous production of prompt same-sign lepton pairs and pair-produced doubly charged Higgs bosons with $ \sqrt{s}=8 $ TeV pp collisions using the ATLAS detector

A low-background inclusive search for new physics in events with same-sign dileptons is presented. The search uses proton-proton collisions corresponding to 20.3 fb -1 of integrated luminosity taken in 2012 at a centre-of-mass energy of 8 TeV with the ATLAS detector at the LHC. Pairs of isolated leptons with the same electric charge and large transverse momenta of the type e ± e ± , e ± μ ± , and μ ± μ ± are selected and their invariant mass distribution is examined. No excess of events above the expected level of Standard Model background is found. The results are used to set upper limits on the cross-sections for processes beyond the Standard Model. Limits are placed as a function of the dilepton invariant mass within a fiducial region corresponding to the signal event selection criteria. Exclusion limits are also derived for a specific model of doubly charged Higgs boson production.[Figure not available: see fulltext.]

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Evidence for the Higgs-boson Yukawa coupling to tau leptons with the ATLAS detector

Results of a search for H → ττ decays are presented, based on the full set of proton-proton collision data recorded by the ATLAS experiment at the LHC during 2011 and 2012. The data correspond to integrated luminosities of 4.5 fb –1 and 20.3 fb –1 at centre-of-mass energies of √s=7 TeV and √s=8 TeV respectively. All combinations of leptonic (τ → ℓνν¯ with ℓ = e, μ) and hadronic (τ → hadrons ν) tau decays are considered. An excess of events over the expected background from other Standard Model processes is found with an observed (expected) significance of 4.5 (3.4) standard deviations. This excess provides evidence for the direct coupling of the recently discovered Higgs boson to fermions. The measured signal strength, normalized to the Standard Model expectation, of μ = 1.43 –0.37 +0.43 is consistent with the predicted Yukawa coupling strength in the Standard Model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Search for the standard model Higgs boson produced in association with a vector boson and decaying into a tau pair in p p collisions at s = 8 TeV with the ATLAS detector

A search for the standard model Higgs boson produced in association with a vector boson with the decay H → τ τ is presented. The data correspond to 20.3 fb -1 of integrated luminosity from proton-proton collisions at √ s = 8 TeV recorded by the ATLAS experiment at the LHC during 2012.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2017

Vectorlike leptons: Muon g - 2 anomaly, lepton flavor violation, Higgs boson decays, and lepton nonuniversality

Here, we discuss the Standard Model (SM) with one family of vectorlike (VL) leptons, which couple to all three families of the SM leptons. We study the constraints on this model coming from the heavy-charged lepton mass bound, electroweak precision data, the muon anomalous magnetic moment, lepton flavor violation, Higgs boson decay constraints, and a recently measured lepton nonuniversality observable, R K * 0 , along with R K . We find that the strongest constraints are coming from the muon g - 2 , R μ μ = Γ ( h → μ μ ) / Γ ( h → μ μ ) SM , R γ γ and BR ( μ → e γ ) . While VL leptons couple to all three families of the SM leptons, the ratio of electron-VL to muon-VL coupling is constrained to be 〈 λ e / λ μ 〉 ≲ 10 - 4 . We also find that this model cannot fit the lepton nonuniversality discrepancies.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for Higgs Boson pair production in the γ γ b b ¯ final state using p p collision data at s = 8 TeV from the ATLAS Detector

Searches are performed for resonant and nonresonant Higgs boson pair production in the γγbb¯ final state using 20 fb⁻¹ of proton-proton collisions at a center-of-mass energy of 8 TeV recorded with the ATLAS detector at the CERN Large Hadron Collider. A 95% confidence level upper limit on the cross section times branching ratio of nonresonant production is set at 2.2 pb, while the expected limit is 1.0 pb. The difference derives from a modest excess of events, corresponding to 2.4 standard deviations from the background-only hypothesis. The limit observed in the search for a narrow X → hh resonance ranges between 0.7 and 3.5 pb as a function of the resonance mass.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2015

Search for direct pair production of a chargino and a neutralino decaying to the 125 GeV Higgs boson in √s = 8 TeV pp collisions with the ATLAS detector

A search is presented for the direct pair production of a chargino and a neutralino pp→ χ~± 1 χ ~0 2 , where the chargino decays to the lightest neutralino and the W boson, χ ~± 1 →χ ~0 1 (W ± → ℓ ± ν), while the neutralino decays to the lightest neutralino and the 125 GeV Higgs boson, χ ~0 2 →χ ~0 1 (h → bb/γγ/ℓ ± νqq). The final states considered for the search have large missing transverse momentum, an isolated electron or muon, and one of the following: either two jets identified as originating from bottom quarks, or two photons, or a second electron or muon with the same electric charge. The analysis is based on 20.3 fb -1 of √s=8 TeV proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with the Standard Model expectations; limits are set in the context of a simplified super-symmetric model.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Search for the Higgs Boson and for Anomalous Quartic Gauge Boson Couplings in the WW Channel with Dielectron Events with the D0 Experiment at the Tevatron; Recherche du boson de Higgs et de couplages de jauge quartiques anormaux dans le canal WW en électrons dans l'expérience D0 au Tevatron

Le paysage de la physique des particules a subi des changements majeurs entre le début de cette thèse, en septembre 2010, et sa n en juin 2013. On peut notamment qualier l'année 2012 de date-clé dans l'histoire de la physique des particules. En 2012, une nouvelle particule a été découverte au LHC [1, 2], dont la majeure partie de la communauté s'accorde aujourd'hui à dire qu'il s'agit très probablement du boson de Higgs. Cet événement est intervenu peu après une sorte de passage de relais entre le Tevatron, arrêté le 30 septembre 2011, et le LHC, dont les toutes premières collisions sont intervenues le 23 novembre 2009.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗