Author: Mathis FrahmPublisher:
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Languages : en
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Book Description
Search for Non-resonant Higgs Boson Pair Production in the Lepton+jets Final State of the BbWW Decay Mode at CMS
Author: Mathis FrahmStudying the Boosted Regime in a Search for Non-resonant Higgs Boson Pair Production in the Lepton+jets Final State of the BbWW Decay Mode at CMS
Author: Janek MölsSearch for the Higgs Boson in Lepton, Tau, and Jets Final States
Author: Publisher:
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Languages : en
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Book Description
We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with two or more jets using 9.7 fb-1 of Run II Fermilab Tevatron Collider data collected with the D0 detector. The analysis is sensitive to Higgs boson production via gluon fusion, associated vector boson production, and vector boson fusion, followed by the Higgs boson decay to tau lepton pairs or to W boson pairs. The ratios of 95% C.L. upper limits on the cross section times branching ratio to those predicted by the standard model are obtained for orthogonal subsamples that are enriched in either H → [tau] [tau] decays or H → WW decays, and for the combination of these subsample limits. The observed and expected limit ratios for the combined subsamples at a Higgs boson mass of 125 GeV are 11.3 and 9.0 respectively.
Search for Higgs Boson Pair Production in the Γγbb ̄ Final State Using Pp Collision Data at √s
Author: Publisher:
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Languages : en
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Book Description
A search for Higgs boson pair production \(pp \rightarrow hh\) is performed with 19.5 fb\(^{-1}\) of proton-proton collision data at \(\sqrt{s}=8\) TeV, which were recorded by the ATLAS detector at the Large Hadron Collider in 2012. The decay products of each Higgs boson are reconstructed as a high-momentum \(b\bar{b}\) system with either a pair of small-radius jets or a single large-radius jet, the latter exploiting jet substructure techniques and associated b-tagged track-jets. No evidence for resonant or non-resonant Higgs boson pair production is observed. The data are interpreted in the context of the Randall-Sundrum model with a warped extra dimension as well as the two-Higgs-doublet model. An upper limit on the cross-section for \(pp\rightarrow G^{*}_{\mathrm {KK}} \rightarrow hh \rightarrow b\bar{b}b\bar{b} \) of 3.2 (2.3) fb is set for a Kaluza-Klein graviton \(G^{*}_{\mathrm {KK}}\) mass of 1.0 (1.5) TeV, at the 95 % confidence level. The search for non-resonant Standard Model hh production sets an observed 95 % confidence level upper limit on the production cross-section \(\sigma (pp \rightarrow hh \rightarrow b\bar{b}b\bar{b})\) of 202 fb, compared to a Standard Model prediction of \(\sigma (pp \rightarrow hh \rightarrow b\bar{b}b\bar{b}) = 3.6 \pm 0.5\) fb.
Search for Nonresonant Higgs Boson Pair Production in Final States with Two Bottom Quarks and Two Photons in Proton-proton Collisions at √s
Author: Albert M. SirunyanSearch for W' $\to $ Tb Decays in the Lepton + Jets Final State in Pp Collisions at $\sqrt{s}$
Author: Publisher:
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Languages : en
Pages : 35
Book Description
Results are presented from a search for the production of a heavy gauge boson W' decaying into a top and a bottom quark, using a data set collected by the CMS experiment at sqrt(s) = 8 TeV and corresponding to an integrated luminosity of 19.5 inverse femtobarns. Various models of W'-boson production are studied by allowing for an arbitrary combination of left- and right-handed couplings. The analysis is based on the detection of events with a lepton (e, mu), jets, and missing transverse energy in the final state. No evidence for W'-boson production is found and 95% confidence level upper limits on the production cross section times branching fraction are obtained. For W' bosons with purely right-handed couplings, and for those with left-handed couplings assuming no interference effects, the observed 95% confidence level limit is M(W')> 2.05 TeV. For W' bosons with purely left-handed couplings, including interference effects, the observed 95% confidence level limit is M(W')> 1.84 TeV. The results presented in this paper are the most stringent limits published to date.
Search for Resonant Pair Production of Higgs Bosons in the Bb ̄bb ̄ Final State Using Pp Collisions at S
Author: [Study Group] ATLAS Collaboration CERNPublisher:
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Languages : en
Pages : 0
Book Description
Abstract: A search for resonant Higgs boson pair production in the b ̄bb ̄b final state is presented. The analysis uses 126 fb−1-139 fb−1 of pp collision data at √s=13 TeV collected with the ATLAS detector at the Large Hadron Collider. The analysis is divided into two channels, targeting Higgs boson decays which are reconstructed as pairs of small-radius jets or as individual large-radius jets. Spin-0 and spin-2 benchmark signal models are considered, both of which correspond to resonant HH production via gluon-gluon fusion. The data are consistent with Standard Model predictions. Upper limits are set on the production cross section times branching ratio to Higgs boson pairs of a new resonance in the mass range from 251 GeV to 5 TeV
Search for Resonant and Nonresonant Higgs Boson Pair Production in the Bb ̄lνlν Final State in Proton-proton Collisions at S√
Author: Identification of $\tau$ Leptons and Higgs Boson Search in the $\mu+\tau$ Final State at the D0 Experiment at the Tevatron
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Languages : en
Pages : 274
Book Description
The gauge symmetry is the heart of our understanding of the electroweak interaction and describes all the current experimental results. However, the intrinsic incompatibility between the gauge invariance and the mass of particles leads to the introduction of a new particle, the Higgs boson, for which we have no experimental evidence as of today. This thesis describes the Higgs boson search in the [mu] + [tau] final state in 7.3 fb-1 of pp collisions at √s = 1.96 TeV collected by the DØ detector at the Tevatron. This analysis completes the golden channels (dimuons, electron-muon, dielectrons) exploiting the decay chain H → WW → lvlv , which is the main Higgs boson decay mode in the mass window accessible to the Tevatron. Since the final state includes a lepton, work was done to improve their identification among jets. An increase of 15% was achieved thanks to the the following : changing tuning parameters for the identification neural network, use of the kinematical dependence of the algorithm performances, incorporation of the [tau] lepton life time information and full study of the additionnal information coming from the central preshower measurements. Then, since the dominant background of the [mu] + [tau] Higgs boson search is W+jets (where one jet fakes a [tau] ), a method was developed to obtain good modeling of this background, not provided by the default simulation. This method is based, among other things, on the charge correlation between the muon and the [tau] candidate which allows for calibration of this background in the data excluding the signal region. Finally, all the kinematic and/or topological differences between the signal and the background were exploited to optimize this search, reaching an (observed) expected sensitivity of 7.8 (6.6) times the Standard Model for mH = 165 GeV=c2. In addition, this result was also interpreted in a fourth fermion generation scenario. For the first time, this analysis is included in the D and Tevatron combinations, both presented at Moriond EW and EPS 2011.
Author: Nikolina Ilic