Search for Higgs bosons with b-jets in the final state in proton-proton collisions with the ATLAS experiment

Hochschulschrift

Zusammenfassung: This thesis discusses searches for Higgs bosons in decays with b-quark jets in the final state in data from proton-proton collisions taken with the ATLAS detector at the Large Hadron Collider (LHC).First, a search for the Standard Model (SM) Higgs boson in the associated production with a vector boson and the decay to b-quarks, VH(bb), is presented. It is based on the data recorded during Run 1 of the LHC at a center-of-mass energy of sqrt(s) = 8 TeV, corresponding to an integrated luminosity of 20.3/fb. Other SM processes yield backgrounds with cross sections much larger than for the expected Higgs boson signal. Their contribution is efficiently separated from the signal using Boosted Decision Trees (BDT). The signal contribution is estimated using a profile likelihood fit of the BDT output distributions.The signal strength with respect to the SM expectation is measured to be 0.65+0.43-0.40, corresponding to an observed (expected) significance of 1.7 (2.5) standard deviations. In combination with the analysis performed using the data taken at sqrt(s) = 7 TeV the signal strength is measured to be 0.51+0.40-0.37, corresponding to an observed (expected) significance of 1.4 (2.6) standard deviations.Additionally, a sensitivity estimate of the SM Higgs boson produced in gluon-fusion and decaying to two b quarks, gg->H->bb, is presented. This feasibility study is based on the data taken at sqrt(s) = 8 TeV. The expected statistical significance has been estimated to be 0.7 standard deviations from a likelihood ratio based on the dijet mass.The second analysis presented in this thesis is a search for decays of the Higgs boson to Beyond Standard Model (BSM) particles that are invisible to the ATLAS detector. The search has been performed in the associated production with a hadronically decaying vector boson, V(qq)H(inv). Also this analysis is based on the data taken at sqrt(s) = 8 TeV.

Angaben zum Objekt

• Standort: Deutsche Nationalbibliothek Frankfurt am Main
• Umfang: Online-Ressource
• Sprache: Englisch
• Anmerkungen: Albert-Ludwigs-Universität Freiburg, Dissertation, 2016

Klassifikation und Themen

• Klassifikation: Physik
• Schlagwort: Physik ; Elementarteilchenphysik ; LHC ; ATLAS ; Higgs-Teilchen ; b-Quark

Beteiligte, Orts- und Zeitangaben

• Ereignis: Veröffentlichung
• (wo): Freiburg
• (wer): Universität
• (wann): 2016
• Urheber: Büscher, Daniel
• Beteiligte Personen und Organisationen: Jakobs, Karl

Weitere Informationen

• DOI: 10.6094/UNIFR/11321
• URN: urn:nbn:de:bsz:25-freidok-113210
• Rechteinformation: Der Zugriff auf das Objekt ist unbeschränkt möglich.
• Letzte Aktualisierung: 25.03.2025, 13:55 MEZ