Combination of Searches for WW, WZ, and ZZ Resonances in Pp Collisions at

Combination of Searches for WW, WZ, and ZZ Resonances in Pp Collisions at
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Total Pages: 21
Release: 2016
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In this study, the ATLAS experiment at the CERN Large Hadron Collider has performed searches for new, heavy bosons decaying to WW, WZ, and ZZ final states in multiple decay channels using 20.3 fb-12 of pp collision data at √s=8 TeV. In the current study, the results of these searches are combined to provide a more stringent test of models predicting heavy resonances with couplings to vector bosons. Direct searches for a charged diboson resonance decaying to WZ in the l?l'l' (l=?,e), llqq¯,l?qq¯ and fully hadronic final states are combined and upper limits on the rate of production times branching ratio to the WZ bosons are compared with predictions of an extended gauge model with a heavy W' boson. Also, direct searches for a neutral diboson resonance decaying to WW and ZZ in the llqq¯, l?qq¯, and fully hadronic final states are combined and upper limits on the rate of production times branching ratio to the WW and ZZ bosons are compared with predictions for a heavy, spin-2 graviton in an extended Randall–Sundrum model where the Standard Model fields are allowed to propagate in the bulk of the extra dimension.

Search for Massive Resonances Decaying Into WW, WZ Or ZZ Bosons in Proton-proton Collisions at Sqrt(s)

Search for Massive Resonances Decaying Into WW, WZ Or ZZ Bosons in Proton-proton Collisions at Sqrt(s)
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Release: 2016
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A search is presented for new massive resonances decaying to WW, WZ or ZZ bosons in l nu quark anti-quark and quark anti-quark quark anti-quark final states. Results are based on data corresponding to an integrated luminosity of 2.3-2.7 inverse femtobarns recorded in proton-proton collisions at sqrt(s) = 13 TeV with the CMS detector at the LHC. Decays of spin-1 and spin-2 resonances into two vector bosons are sought in the mass range 0.6-4.0 TeV. No significant excess over the standard model background is observed. Combining the results of the l nu quark anti-quark and quark anti-quark quark anti-quark final states, cross section and mass exclusion limits are set for models that predict heavy spin-1 and spin-2 resonances. This is the first search for a narrow-width spin-2 resonance at sqrt(s) = 13 TeV.

Search for New Resonances in W? and Z? Final States in Pp Collisions at {u221A} S

Search for New Resonances in W? and Z? Final States in Pp Collisions at {u221A} S
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Total Pages: 20
Release: 2014
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This Letter presents a search for new resonances decaying to final states with a vector boson produced in association with a high transverse momentum photon, V? , with V=W(→l?) or Z(→l+l-), where l=e or ?. The measurements use 20.3 fb-1 of proton–proton collision data at a center-of-mass energy of √s = 8 TeV recorded with the ATLAS detector. No deviations from the Standard Model expectations are found, and production cross section limits are set at 95% confidence level. Masses of the hypothetical aT and ?T states of a benchmark Low Scale Technicolor model are excluded in the ranges [275,960] GeV and [200,700]?[750,890] GeV, respectively. Limits at 95% confidence level on the production cross section of a singlet scalar resonance decaying to Z? final states have also been obtained for masses below 1180 GeV.

Search for Resonant WW and WZ Production in Ppbar Collisions At?s

Search for Resonant WW and WZ Production in Ppbar Collisions At?s
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Release: 2010
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The standard model of particle physics is expected to be a low energy effective theory valid for particle interactions below the TeV scale. Above this scale, extensions to the standard model (SM) augment the existing particle content, leading to enhanced production of many final states at colliders. Specifically, the production and decay of massive charged or neutral particles can produce an excess of W boson pairs for neutral particles or W and Z boson pairs for charged particles. We search for resonant WW or WZ production using up to 5.4 fb−1 of integrated luminosity collected by the D0 experiment in Run II of the Fermilab Tevatron Collider. The data are consistent with the standard model background expectation, and we set limits on a resonance mass using the sequential standard model (SSM) W(prime) boson and the Randall-Sundrum model graviton G as benchmarks. We exclude an SSM W(prime) boson in the mass range 180-690 GeV and a Randall-Sundrum graviton in the range 300-754 GeV at 95% CL.

Search for WZ Resonances in the Fully Leptonic Channel Using Pp Collisions at {u221A}s

Search for WZ Resonances in the Fully Leptonic Channel Using Pp Collisions at {u221A}s
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Total Pages: 21
Release: 2014
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A search for resonant WZ production in the l?l'l' (l,l'=e,?) decay channel using 20.3 fb-1 of √s = 8 TeV pp collision data collected by the ATLAS experiment at LHC is presented. No significant deviation from the Standard Model prediction is observed and upper limits on the production cross sections of WZ resonances from an extended gauge model W' and from a simplified model of heavy vector triplets are derived. As a result, a corresponding observed (expected) lower mass limit of 1.52 (1.49) TeV is derived for the W' at the 95% confidence level.

Search for High Mass Dilepton Resonances in Pp Collisions at $\sqrt{s}

Search for High Mass Dilepton Resonances in Pp Collisions at $\sqrt{s}
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Release: 2011
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This article presents a search for high mass e+e− or ?+?− resonances in pp collisions at √s = 7 TeV at the LHC. The data were recorded by the ATLAS experiment during 2010 and correspond to a total integrated luminosity of ̃40 pb−1. No statistically significant excess above the Standard Model expectation is observed in the search region of dilepton invariant mass above 110 GeV. Upper limits at the 95% confidence level are set on the cross section times branching ratio of Z' resonances decaying to dielectrons and dimuons as a function of the resonance mass. A lower mass limit of 1.048 TeV on the Sequential Standard Model Z' boson is derived, as well as mass limits on Z' and E6-motivated Z' models.

Search for Heavy Lepton Resonances Decaying to a Z Boson and a Lepton in Pp Collisions at \(\sqrt{s}

Search for Heavy Lepton Resonances Decaying to a Z Boson and a Lepton in Pp Collisions at \(\sqrt{s}
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Release: 2015
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A search for heavy leptons decaying to a Z boson and an electron or a muon is presented. The search is based on pp collision data taken at \(\sqrt{s}=8 \) TeV by the ATLAS experiment at the CERN Large Hadron Collider, corresponding to an integrated luminosity of 20.3 fb−1. Three high-transverse-momentum electrons or muons are selected, with two of them required to be consistent with originating from a Z boson decay. No significant excess above Standard Model background predictions is observed, and 95% confidence level limits on the production cross section of high-mass trilepton resonances are derived. The results are interpreted in the context of vector-like lepton and type-III seesaw models. For the vector-like lepton model, most heavy lepton mass values in the range 114-176 GeV are excluded. For the type-III seesaw model, most mass values in the range 100-468 GeV are excluded.

Search for a Dijet Resonance in Events with Jets and Missing Transverse Energy in Pp[over ̄] Collisions at Sqrt[s]

Search for a Dijet Resonance in Events with Jets and Missing Transverse Energy in Pp[over ̄] Collisions at Sqrt[s]
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Release: 2013
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We report on a search for a dijet resonance in events with only two or three jets and large imbalance in the total event transverse momentum. This search is sensitive to the possible production of a new particle in association with a W or Z boson, where the boson decays leptonically with one or more neutrinos in the final state. We use the full data set collected by the CDF II detector at the Tevatron collider at a proton-antiproton center-of-mass energy of 1.96 TeV. These data correspond to an integrated luminosity of 9.1 fb{̂-1}. We study the invariant mass distribution of the two jets with highest transverse energy. We find good agreement between data and standard model background expectations and measure the combined cross section for WW, WZ, and ZZ production to be 13.8{̂+3.0}_{-2.7} pb. No significant anomalies are observed in the mass spectrum and 95% credibility level upper limits are set on the production rates of a potential new particle in association with a W or Z boson.