Cargando…

Search for New Physics through Higgs-Boson-Pair Production at the LHC and Beyond

This thesis presents a search for resonant production of highly energetic Higgs boson pairs, with each Higgs boson decaying to a $b$-quark pair, with the ATLAS detector. This analysis uses the complete ATLAS run 2 dataset of 139.0 $\text{fb}^{-1}$ of proton-proton collisions at a centre-of-mass ene...

Descripción completa

Detalles Bibliográficos
Autor principal: Paredes Saenz, Santiago Rafael
Lenguaje:eng
Publicado: 2021
Materias:
Acceso en línea:http://cds.cern.ch/record/2752606
_version_ 1780969293645611008
author Paredes Saenz, Santiago Rafael
author_facet Paredes Saenz, Santiago Rafael
author_sort Paredes Saenz, Santiago Rafael
collection CERN
description This thesis presents a search for resonant production of highly energetic Higgs boson pairs, with each Higgs boson decaying to a $b$-quark pair, with the ATLAS detector. This analysis uses the complete ATLAS run 2 dataset of 139.0 $\text{fb}^{-1}$ of proton-proton collisions at a centre-of-mass energy of $\sqrt{s}= 13$ TeV. The expanded dataset, new flavour-tagging techniques, and novel subjet reconstruction algorithms provide better sensitivity than previous studies of the process. Two beyond-the-Standard-Model resonances are chosen as benchmarks for the result: a two-Higgs-doublet model scalar $S$ and Kaluza-Klein (KK) gravitons $G_{kk}^*$ predicted in the bulk Randall-Sundrum (RS) model. No significant deviations from Standard Model predictions are found, and upper limits are set on the production cross section of these resonances. A phenomenology study on the analysis strategy of this search in conditions of the future High Luminosity Large Hadron Collider is presented as well. This study shows proof-of-concept improvements in sensitivity by using a deep-learning approach to separate the $hh \to 4b$ signal, and discusses the optimization of the search to constrain the Higgs boson self-coupling parameter $\lambda_{hhh}$.
id cern-2752606
institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2021
record_format invenio
spelling cern-27526062022-01-31T15:06:51Zhttp://cds.cern.ch/record/2752606engParedes Saenz, Santiago RafaelSearch for New Physics through Higgs-Boson-Pair Production at the LHC and BeyondParticle Physics - ExperimentParticle Physics - PhenomenologyThis thesis presents a search for resonant production of highly energetic Higgs boson pairs, with each Higgs boson decaying to a $b$-quark pair, with the ATLAS detector. This analysis uses the complete ATLAS run 2 dataset of 139.0 $\text{fb}^{-1}$ of proton-proton collisions at a centre-of-mass energy of $\sqrt{s}= 13$ TeV. The expanded dataset, new flavour-tagging techniques, and novel subjet reconstruction algorithms provide better sensitivity than previous studies of the process. Two beyond-the-Standard-Model resonances are chosen as benchmarks for the result: a two-Higgs-doublet model scalar $S$ and Kaluza-Klein (KK) gravitons $G_{kk}^*$ predicted in the bulk Randall-Sundrum (RS) model. No significant deviations from Standard Model predictions are found, and upper limits are set on the production cross section of these resonances. A phenomenology study on the analysis strategy of this search in conditions of the future High Luminosity Large Hadron Collider is presented as well. This study shows proof-of-concept improvements in sensitivity by using a deep-learning approach to separate the $hh \to 4b$ signal, and discusses the optimization of the search to constrain the Higgs boson self-coupling parameter $\lambda_{hhh}$.CERN-THESIS-2020-280oai:cds.cern.ch:27526062021-02-19T18:21:03Z
spellingShingle Particle Physics - Experiment
Particle Physics - Phenomenology
Paredes Saenz, Santiago Rafael
Search for New Physics through Higgs-Boson-Pair Production at the LHC and Beyond
title Search for New Physics through Higgs-Boson-Pair Production at the LHC and Beyond
title_full Search for New Physics through Higgs-Boson-Pair Production at the LHC and Beyond
title_fullStr Search for New Physics through Higgs-Boson-Pair Production at the LHC and Beyond
title_full_unstemmed Search for New Physics through Higgs-Boson-Pair Production at the LHC and Beyond
title_short Search for New Physics through Higgs-Boson-Pair Production at the LHC and Beyond
title_sort search for new physics through higgs-boson-pair production at the lhc and beyond
topic Particle Physics - Experiment
Particle Physics - Phenomenology
url http://cds.cern.ch/record/2752606
work_keys_str_mv AT paredessaenzsantiagorafael searchfornewphysicsthroughhiggsbosonpairproductionatthelhcandbeyond