Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.763095
Title: Search for Higgs boson pair production in the bƃbƃ final state at the Large Hadron Collider
Author: Falla, R. J.
ISNI:       0000 0004 7659 9937
Awarding Body: UCL (University College London)
Current Institution: University College London (University of London)
Date of Award: 2016
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Abstract:
The work presented in this thesis focuses on the search for resonant and non-resonant Higgs boson pair production in the bƃbƃ final state at the LHC. All of the searches require the use of high transverse momentum b-tagged jet systems. The first search presented is performed using a dataset of proton- proton collisions at √s = 8 TeV, collected in 2012 with the ATLAS detector, corresponding to an integrated luminosity of 19.5 fb^{-1}. The Higgs boson decay products are reconstructed as a pair of close- by small radius b-tagged jets with a high transverse momentum, known as "dijets". The resonant signals looked for are a Randall- Sundrum Kaluza-Klein graviton, G^*, and a heavy neutral scalar boson in the 2HDM model, H. A non-resonant search is also performed. No evidence for resonant or non-resonant Higgs boson pair production is observed. An upper limit on the cross-section for σ(pp → G^* →hh→bƃbƃ) of 3.2 fb is set for a G^* mass of 1.0 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 σ(pp → hh → bƃbƃ) of 202 fb, compared to a SM prediction of σ(pp → hh → bƃbƃ) = 3.6 ± 0.5 fb. In preparation for Run 2 and the HL-LHC simulation studies based on √s = 14 TeV are made. A non-resonant search using the dijet method used in Run 1 is presented. A resonant study is also presented which shows a new method for reconstructing pp → X →hh→bƃbƃ events. It uses the combination of many Higgs boson reconstruction techniques which vary with the Higgs boson transverse momentum and is shown to be excellent at providing a high signal efficiency.
Supervisor: Konstantinidis, N. Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.763095  DOI: Not available
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