{"id":{"repo_id":"lancaster","oai_identifier":"oai:eprints.lancs.ac.uk:132061"},"canonical_url":"https://search.dev.ndltd.org/etd/lancaster/oai:eprints.lancs.ac.uk:132061","repository":{"repo_id":"lancaster","name":"Lancaster University","base_url":"https://eprints.lancs.ac.uk/cgi/oai2"},"display":{"title":"Beyond the standard model searches with b-jets and hadronically decaying τ-leptons with the ATLAS detector","abstract":"This thesis describes the search for resonant and non-resonant Higgs boson pair production in the b ¯bτ +τ − decay channel. The main focus of this document is on the final state where both τ -leptons decay hadronically. The search is performed using 36.1 fb−1 of data collected by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV during 2015 and 2016. The cross-section for non-resonant di-Higgs production is found to be 16.4 times the Standard Model prediction in the fully hadronic channel at a 95% confidence level. Combining the result with the semi-leptonic channel produces a measured signal strength of µ = 12.7 at a 95% confidence level when compared to the Standard Model prediction. Resonant Higgs boson pair production excludes bulk Randall-Sundrum gravitons GKK in the mass range 325 GeV < mGKK < 885 GeV for k/MP L = 1. For the simplified hMSSM minimal supersymmetric model for tan β = 2, resonances are excluded in the mass range 305 GeV < mH < 402 GeV. Finally, a re-interpretation of the Higgs boson pair production analysis is presented as a search for third-generation scalar leptoquarks. Pair-produced third-generation scalar leptoquarks decaying to bτ bτ are excluded at 95% confidence level for mLQ < 1030 GeV.","abstract_html":"This thesis describes the search for resonant and non-resonant Higgs boson pair production in the b ¯bτ +τ − decay channel. The main focus of this document is on the final state where both τ -leptons decay hadronically. The search is performed using 36.1 fb−1 of data collected by the ATLAS detector in proton-proton collisions at a centre-of-mass energy of 13 TeV during 2015 and 2016. The cross-section for non-resonant di-Higgs production is found to be 16.4 times the Standard Model prediction in the fully hadronic channel at a 95% confidence level. Combining the result with the semi-leptonic channel produces a measured signal strength of µ = 12.7 at a 95% confidence level when compared to the Standard Model prediction. Resonant Higgs boson pair production excludes bulk Randall-Sundrum gravitons GKK in the mass range 325 GeV &lt; mGKK &lt; 885 GeV for k/MP L = 1. For the simplified hMSSM minimal supersymmetric model for tan β = 2, resonances are excluded in the mass range 305 GeV &lt; mH &lt; 402 GeV. Finally, a re-interpretation of the Higgs boson pair production analysis is presented as a search for third-generation scalar leptoquarks. Pair-produced third-generation scalar leptoquarks decaying to bτ bτ are excluded at 95% confidence level for mLQ &lt; 1030 GeV.","abstract_has_math":false,"creators":["Parker, Adam Jackson","Fox, Harald"],"institution":"Lancaster University","degree_name":"Ph.D.","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2019,"date_issued":"2019","date_published":"2019","updated_at":"2026-07-24T02:48:50Z","subjects":[],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Parker, Adam Jackson","Fox, Harald"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2019"]},{"key":"dc:date.issued","label":"Date","values":["2019"]},{"key":"dc:publisher.commercial","label":"Dc Publisher Commercial","values":["Lancaster University"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["Physics"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["Lancaster University"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://eprints.lancs.ac.uk/id/eprint/132061/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["Ph.D."]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://eprints.lancs.ac.uk/id/eprint/132061/4/2019parkerphd.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This thesis describes the search for resonant and non-resonant Higgs boson pair production in the b ¯bτ +τ − decay channel. 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