Combination of Searches for Heavy Resonances Decaying to WW, WZ, ZZ, WH, and ZH Boson Pairs in Proton-proton Collisions at √s

Combination of Searches for Heavy Resonances Decaying to WW, WZ, ZZ, WH, and ZH Boson Pairs in Proton-proton Collisions at √s PDF Author: CMS Collaboration
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Languages : en
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Search for Heavy Resonances Decaying to Tau Lepton Pairs in Proton-proton Collisions at $\sqrt{s}$

Search for Heavy Resonances Decaying to Tau Lepton Pairs in Proton-proton Collisions at $\sqrt{s}$ PDF Author:
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Category :
Languages : en
Pages :

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A search for heavy resonances that decay to tau lepton pairs is performed using proton-proton collisions at \sqrt{s}$ = 13 TeV. The data were collected with the CMS detector at the CERN LHC and correspond to an integrated luminosity of 2.2 inverse femtobarns. The observations are in agreement with standard model predictions. An upper limit at 95% confidence level on the product of the production cross section and branching fraction into tau lepton pairs is calculated as a function of the resonance mass. For the sequential standard model, the presence of Z' bosons decaying into tau lepton pairs is excluded for Z' masses below 2.1 TeV, extending previous limits for this final state. For the topcolor-assisted technicolor model, which predicts Z' bosons that preferentially couple to third-generation fermions, Z' masses below 1.7 TeV are excluded, representing the most stringent limit to date.

Search for Pair-produced Resonances Decaying to Jet Pairs in Proton{u2013}proton Collisions at $\sqrt{s}$

Search for Pair-produced Resonances Decaying to Jet Pairs in Proton{u2013}proton Collisions at $\sqrt{s}$ PDF Author:
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Category :
Languages : en
Pages : 22

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Results are reported of a general search for pair production of heavy resonances decaying to pairs of hadronic jets in events with at least four jets. The study is based on up to 19.4 fb–1 of integrated luminosity from proton–proton collisions at a center-of-mass energy of 8 TeV, recorded with the CMS detector at the LHC. Limits are determined on the production of scalar top quarks (top squarks) in the framework of R-parity violating supersymmetry and on the production of color-octet vector bosons (colorons). First limits at the LHC are placed on top squark production for two scenarios. The first assumes decay to a bottom quark and a light-flavor quark and is excluded for masses between 200 and 385 GeV, and the second assumes decay to a pair of light-flavor quarks and is excluded for masses between 200 and 350 GeV at 95% confidence level. Furthermore, previous limits on colorons decaying to light-flavor quarks are extended to exclude masses from 200 to 835 GeV.

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) PDF Author:
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Category :
Languages : en
Pages :

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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.

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 PDF Author:
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ISBN:
Category :
Languages : en
Pages : 21

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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 Narrow High-mass Resonances in Proton{u2013}proton Collisions at $\sqrt{s}$

Search for Narrow High-mass Resonances in Proton{u2013}proton Collisions at $\sqrt{s}$ PDF Author:
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ISBN:
Category :
Languages : en
Pages : 23

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A search for a narrow, high-mass resonance decaying into Z and Higgs (H) bosons is presented. The final state studied consists of a merged jet pair and a ? pair resulting from the decays of Z and H bosons, respectively. This analysis is based on a data sample of proton–proton collisions at a center-ofmass energy of 8 TeV, collected with the CMS experiment in 2012, and corresponding to an integrated luminosity of 19.7 fb-1. In the resonance mass range of interest, which extends from 0.8 to 2.5 TeV, the Z and H bosons are produced with large momenta, which implies that the final products of the two quarks or the two ? leptons must be detected within a small angular interval. A combination of all possible decay modes of the ? leptons, production cross sections in a range between 0.9 and 27.8 fb are excluded at 95% confidence level, depending on the resonance mass.

Search for Pair-produced Resonances Decaying to Jet Pairs in Proton-proton Collisions at [arrow]"

Search for Pair-produced Resonances Decaying to Jet Pairs in Proton-proton Collisions at [arrow] Author:
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ISBN:
Category :
Languages : en
Pages : 31

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Book Description
Results are reported of a general search for pair production of heavy resonances decaying to pairs of jets in events with at least four jets. The study is based on up to 19.4 inverse femtobarns of integrated luminosity from proton-proton collisions at a center-of-mass energy of 8 TeV, recorded with the CMS detector at the LHC. Limits are determined on the production of scalar top quarks (top squarks) in the framework of R-parity violating supersymmetry and on the production of color-octet vector bosons (colorons). First limits at the LHC are placed on top squark production for two scenarios. The first assumes decay to a bottom quark and a light-flavor quark and is excluded for masses between 200 and 385 GeV, and the second assumes decay to a pair of light-flavor quarks and is excluded for masses between 200 and 350 GeV at 95% confidence level. Previous limits on colorons decaying to light-flavor quarks are extended to exclude masses from 200 to 835 GeV.

Search for Heavy Resonance Decays Into Top-quark Pairs Using a Lepton-plus-jets Final State in Proton-proton Collisions at √s

Search for Heavy Resonance Decays Into Top-quark Pairs Using a Lepton-plus-jets Final State in Proton-proton Collisions at √s PDF Author: Kyle Krowpman
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ISBN:
Category : Electronic dissertations
Languages : en
Pages : 0

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This thesis presents two studies in a search for new heavy resonances with 139 fb-1 of proton-proton collisions delivered by the Large Hadron Collider at √s = 13 TeV as measured by the ATLAS detector. In many Standard Model extensions, the top quark plays an important role in the dynamics of electroweak symmetry breaking, and so the studies presented here focus on heavy resonance searches in the top-antitop decay channel and their combination with searches for heavy resonances decaying into other final states. The first study detailed in this thesis is a search for new heavy resonances in a semileptonically decaying top-antitop final state where no significant excesses of data were observed with respect to the background prediction. That being so, exclusion limits at the 95% confidence level were placed on possible resonant masses for a Z′ in a leptophobic topcolor-assisted technicolor model and for a bulk Randall-Sundrum graviton at 4.2 TeV and 1.0 TeV, respectively. This top-antitop search was combined with searches in orthogonal final states performed by the ATLAS Collaboration from which limit contours were placed at the 95% confidence level in the space of couplings to Standard Model particles for the Heavy Vector Triplet model.

Search for Massive Resonances Decaying Into Pairs of Boosted Bosons in Semi-leptonic Final States at $\sqrt{s}

Search for Massive Resonances Decaying Into Pairs of Boosted Bosons in Semi-leptonic Final States at $\sqrt{s} PDF Author:
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ISBN:
Category :
Languages : en
Pages : 59

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Book Description
Our search for new resonances decaying to WW, ZZ, or WZ is presented. Final states are considered in which one of the vector bosons decays leptonically and the other hadronically. Results are based on data corresponding to an integrated luminosity of 19.7 fb-1 recorded in proton-proton collisions at √s = 8 TeV with the CMS detector at the CERN LHC. Techniques aiming at identifying jet substructures are used to analyze signal events in which the hadronization products from the decay of highly boosted W or Z bosons are contained within a single reconstructed jet. Upper limits on the production of generic WW, ZZ, or WZ resonances are set as a function of the resonance mass and width. We also increase the sensitivity of the analysis by statistically combining the results of this search with a complementary study of the all-hadronic final state. Upper limits at 95% confidence level are set on the bulk graviton production cross section in the range from 700 to 10 fb for resonance masses between 600 and 2500 GeV, respectively. These limits on the bulk graviton model are the most stringent to date in the diboson final state.

Search for Heavy Resonances Decaying to Two Higgs Bosons in Final States Containing Four B Quarks

Search for Heavy Resonances Decaying to Two Higgs Bosons in Final States Containing Four B Quarks PDF Author:
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Category :
Languages : en
Pages :

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Book Description
A search is presented for narrow heavy resonances X decaying into pairs of Higgs bosons (H) in proton-proton collisions collected by the CMS experiment at the LHC at sqrt(s)=8 TeV. The data correspond to an integrated luminosity of 19.7 inverse femtobarns. The search considers HH resonances with masses between 1 and 3 TeV, having final states of two b quark pairs. Each Higgs boson is produced with large momentum, and the hadronization products of the pair of b quarks can usually be reconstructed as single large jets. The background from multijet and t-tbar events is significantly reduced by applying requirements related to the flavor of the jet, its mass, and its substructure. The signal would be identified as a peak on top of the dijet invariant mass spectrum of the remaining background events. No evidence is observed for such a signal. Upper limits obtained at 95% confidence level for the product of the production cross section and branching fraction sigma(gg to X) B(X to HH to b-bbar b-bbar) range from 10 to 1.5 fb for the mass of X from 1.15 to 2.0 TeV, significantly extending previous searches. For a warped extra dimension theory with a mass scale Lambda[R] = 1 TeV, the data exclude radion scalar masses between 1.15 and 1.55 TeV.