Evidence for Standard Model Higgs Boson Decays to Tau Lepton Pairs in the ATLAS Detector Supported by a Search in the Fully Hadronic Final State
Author: Edmund Noel Dawe
Publisher:
Published: 2014
Total Pages: 195
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Author: Edmund Noel Dawe
Publisher:
Published: 2014
Total Pages: 195
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DOWNLOAD EBOOKAuthor: Gebrüder Heller
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Published: 1995
Total Pages: 6
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DOWNLOAD EBOOKAuthor: Thomas Schwindt
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Published: 2015
Total Pages:
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DOWNLOAD EBOOKAuthor: Thomas Schwindt
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Published: 2015
Total Pages:
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DOWNLOAD EBOOKAuthor: Jessica Kristina Liebal
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Published: 2016
Total Pages:
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DOWNLOAD EBOOKAuthor: Daniele Zanzi
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Published: 2014
Total Pages: 164
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DOWNLOAD EBOOKAuthor: Michel Trottier-McDonald
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Published: 2014
Total Pages: 269
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DOWNLOAD EBOOKThis thesis reports the search for the Higgs boson decaying to a pair of tau leptons, where one tau decays leptonically and the other decays semi-hadronically. The search was conducted by the ATLAS experiment on the proton-proton collisions supplied by the LHC in 2012. It is complicated by background from a mix of known processes from the Standard Model of Particle Physics. It makes use of boosted decision trees to separate the Higgs signal from the background. The gluon-gluon fusion and the vector boson fusion production mechanisms are searched for separately. The statistical significance of the excess observed over the background-only hypothesis is 3.3 standard deviations, and reaches 4.1 standard deviations when combined with other ditau channels. The observed signal appears fully compatible with the Higgs boson of the Standard Model.
Author: Mark Andrew Pickering
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Published: 2016
Total Pages:
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DOWNLOAD EBOOKAuthor: Sebastian Stern
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Published: 2013
Total Pages: 0
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DOWNLOAD EBOOKAuthor: Laura Margaret Dodd
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Published: 2018
Total Pages: 0
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DOWNLOAD EBOOKA search for the standard model (SM) Higgs boson which decays to a pair of [tau] leptons is presented in this thesis using 35.9 f b−1 of 13 TeV data collected in 2016 by the CMS detector at CERN. The final states considered require that (1) one [tau] lepton decays leptonically while the other decays hadronically ([mu][tau]h or e[tau]h), (2) both taus decay hadronically ([tau]h[tau]h) or (3) one tau lepton decays to an electron while the other decays to a muon (e[mu]). This thesis specifically focuses on the details of the semi-hadronic decay channels ([mu][tau]h and e[tau]h), and presents the results of all channels combined. The signal strength, [mu], relative to the expectation for the SM Higgs boson is measured to be [mu] = 1.09+0.27−0.24. An excess is observed (expected) corresponding to 4.9 (4.7) [sigma] using 2016 data. The observed (expected) significance reaches 5.9 (5.9) [sigma] when combined with 7 and 8 TeV data collected at CMS. Subsequently following the SM search, a search for dark matter (DM) is presented and interpreted in two simplified Higgs-portal models: a baryonic dark matter model and a two Higgs-doublet model. In this thesis, the Higgs boson is required to decay to an opposite- sign tau pair. The tau pair final states considered are e[tau]h, [mu][tau]h, and [tau]h[tau]h. The expected 95% confidence level upper limits are produced and compared with the observed limit. No significant deviations beyond the SM prediction are observed.