Search for Resonant Higgs Boson Pair Production in the Bb̄WW* Decay Channel in the Boosted 1-lepton Final State Using the Full Run 2 ATLAS Dataset
Search for Resonant Higgs Boson Pair Production in the Bb̄WW* Decay Channel in the Boosted 1-lepton Final State Using the Full Run 2 ATLAS Dataset

Author: Kira Abeling

Publisher:

Published: 2022

Total Pages:

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Despite the great success of the Standard Model of Particle Physics in explaining physics phenomena over a wide range of energy scales, many open questions remain and it is known that this model of nature is incomplete. The Higgs boson as the most recent discovered particle has completed the Standard Model. With its coupling to mass, it is an excellent candidate to shed light on physics beyond the Standard Model. This thesis presents the search for resonant Higgs boson pair (HH) production as well as resonant production of a Higgs boson in association with another additional scalar particle...

Search for Resonant Pair Production of Higgs Bosons in the Bb ̄bb ̄ Final State Using Pp Collisions at S
Search for Resonant Pair Production of Higgs Bosons in the Bb ̄bb ̄ Final State Using Pp Collisions at S

Author: [Study Group] ATLAS Collaboration CERN

Publisher:

Published: 2022

Total Pages: 0

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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 a Standard Model Higgs Boson in the Channel $VH\to VWW$ with Leptons and Hadronic $\tau$ in the Full CDF Run II Data Set
Search for a Standard Model Higgs Boson in the Channel $VH\to VWW$ with Leptons and Hadronic $\tau$ in the Full CDF Run II Data Set

Author:

Publisher:

Published: 2015

Total Pages: 106

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We present the results of the CDF search for a Standard Model Higgs boson decaying into a pair of W bosons with electrons, muons and hadronically decaying taus in the final state. In particular, we investigate a channel with three objects, two leptons and a tau. In 9.7 fb-1 of data we expect 40.0 ± 5.4 background events and 0.54 ± 0.05 signal events for a Higgs mass hypothesis of 160 GeV/c2, whereas in data we count 28 events. We set a 95% C.L. upper limit on [sigma]/[sigma]SM of 12.6 for a Higgs mass hypothesis of 160 GeV/c2. The expected 95% C.L. upper limit for the same mass is 12.4. Results for other ninete 0 GeV/c2 to 200 GeV/c2 are also presented.

Measurement of Higgs Boson Production and Properties in the WW Decay Channel with Leptonic Final States
Measurement of Higgs Boson Production and Properties in the WW Decay Channel with Leptonic Final States

Author:

Publisher:

Published: 2014

Total Pages: 86

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A search for the standard model Higgs boson decaying to a W-boson pair at the LHC is reported. The event sample corresponds to an integrated luminosity of 4.9 and 19.4 inverse femtobarns collected with the CMS detector in pp collisions at √s = 7 and 8 TeV, respectively. The Higgs boson candidates are selected in events with two or three charged leptons. An excess of events above background is observed, consistent with the expectation from the standard model Higgs boson with a mass of around 125 GeV. The probability to observe an excess equal or larger than the one seen, under the background-only hypothesis, corresponds to a significance of 4.3 standard deviations for mH = 125.6 GeV. The observed signal cross section times the branching fraction to WW for mH = 125.6 GeV is 0.72+0.20-0.18 times the standard model expectation. The spin-parity JP=0+ hypothesis is favored against a narrow resonance with JP=2+ or JP=0- that decays to a W-boson pair. Lastly, this result provides strong evidence for a Higgs-like boson decaying to a W-boson pair.

Heavy Higgs Boson Search in the Four Lepton Decay Channel with the ATLAS Detector
Heavy Higgs Boson Search in the Four Lepton Decay Channel with the ATLAS Detector

Author: Denys Denysiuk

Publisher:

Published: 2017

Total Pages: 0

ISBN-13:

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The thesis is focused on the heavy Higgs boson search in four lepton decay channelwith Run-2 data from the ATLAS detector at the Large Hadron Collider. The analysis publishedat ICHEP 2016 conference that is based on 14.8 fb-1 of 13 TeV data is described in details, whilethe updated results that include 36.1 fb-1 of 13 TeV data are shown as well. The heavy Higgssearch is carried out in a model independent way and it is covering different signal widthhypotheses: narrow width approximation that assumes the signal natural width to be negligiblecomparing to the detector resolution, and the large width assumption including an effect of theinterference with the Standard Model backgrounds. The search that benefits from additionalkinematic discriminant under the scalar signal assumption is presented as well. Thismodification allows to increase the analysis sensitivity up to 25%.The thesis also discusses an upgrade of the ATLAS Muons Spectrometer, namely the NewSmall Wheel project. In particular, simulation of the cavern background that will affect theupgraded detector and commissioning of the Micromegas modules produced at CEA-Saclay forthe New Small Wheel are described.

Search for the Higgs Boson in Lepton, Tau, and Jets Final States
Search for the Higgs Boson in Lepton, Tau, and Jets Final States

Author:

Publisher:

Published: 2013

Total Pages:

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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.