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Searches for Sub-TeV Hadronic Resonances with the ATLAS Detector

The Large Hadron Collider has recently began colliding proton beams at a record center-of-mass energy $\sqrt{s}=13~\TeV$. This allows the LHC experiments to drastically improve searches for heavy new particles. However at the same time, the more complicated environment means an increase in the trigg...

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Autor principal: Krizka, Karol
Lenguaje:eng
Publicado: 2017
Materias:
Acceso en línea:http://cds.cern.ch/record/2258823
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author Krizka, Karol
author_facet Krizka, Karol
author_sort Krizka, Karol
collection CERN
description The Large Hadron Collider has recently began colliding proton beams at a record center-of-mass energy $\sqrt{s}=13~\TeV$. This allows the LHC experiments to drastically improve searches for heavy new particles. However at the same time, the more complicated environment means an increase in the trigger thresholds. Consequently a viable set of theories at lower energies remains unexplored. This thesis describes three ATLAS analyses that used different techniques to target new particles with sub-TeV mass. The first analysis searches for the Higgs boson produced via vector-boson fusion and decaying to two bottom quarks in in $\sqrt{s}=8~\TeV$ dataset. The presence of the extra jets from vector-boson fusion and $b$-tagging is used to reduce the event rate to a manageable level. The second analysis searches for generic resonances decaying to two $b$-quarks with masses between $600~\GeV$ to $1.2~\TeV$. The use of $b$-tagging in the trigger allows it to set unique limits in the sub-TeV mass range. The third analysis searches for hadronic resonances produced in associtaion with energetic initial state radiation (ISR). The use of the ISR as a trigger decorrelates the resonance mass from the trigger efficiency. The result is world-class limits on new particles with masses between $200~\GeV$ to $500~\GeV$. This space is interesting for particles mediating between the Standard Model and the dark sector. The dark matter relic density prefers $\order{100~\GeV}$ mediators, yet the most stringent constraints in this region previously came from the pre-LHC era.
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institution Organización Europea para la Investigación Nuclear
language eng
publishDate 2017
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spelling cern-22588232019-09-30T06:29:59Zhttp://cds.cern.ch/record/2258823engKrizka, KarolSearches for Sub-TeV Hadronic Resonances with the ATLAS DetectorParticle Physics - ExperimentThe Large Hadron Collider has recently began colliding proton beams at a record center-of-mass energy $\sqrt{s}=13~\TeV$. This allows the LHC experiments to drastically improve searches for heavy new particles. However at the same time, the more complicated environment means an increase in the trigger thresholds. Consequently a viable set of theories at lower energies remains unexplored. This thesis describes three ATLAS analyses that used different techniques to target new particles with sub-TeV mass. The first analysis searches for the Higgs boson produced via vector-boson fusion and decaying to two bottom quarks in in $\sqrt{s}=8~\TeV$ dataset. The presence of the extra jets from vector-boson fusion and $b$-tagging is used to reduce the event rate to a manageable level. The second analysis searches for generic resonances decaying to two $b$-quarks with masses between $600~\GeV$ to $1.2~\TeV$. The use of $b$-tagging in the trigger allows it to set unique limits in the sub-TeV mass range. The third analysis searches for hadronic resonances produced in associtaion with energetic initial state radiation (ISR). The use of the ISR as a trigger decorrelates the resonance mass from the trigger efficiency. The result is world-class limits on new particles with masses between $200~\GeV$ to $500~\GeV$. This space is interesting for particles mediating between the Standard Model and the dark sector. The dark matter relic density prefers $\order{100~\GeV}$ mediators, yet the most stringent constraints in this region previously came from the pre-LHC era.CERN-THESIS-2017-023oai:cds.cern.ch:22588232017-04-06T17:01:34Z
spellingShingle Particle Physics - Experiment
Krizka, Karol
Searches for Sub-TeV Hadronic Resonances with the ATLAS Detector
title Searches for Sub-TeV Hadronic Resonances with the ATLAS Detector
title_full Searches for Sub-TeV Hadronic Resonances with the ATLAS Detector
title_fullStr Searches for Sub-TeV Hadronic Resonances with the ATLAS Detector
title_full_unstemmed Searches for Sub-TeV Hadronic Resonances with the ATLAS Detector
title_short Searches for Sub-TeV Hadronic Resonances with the ATLAS Detector
title_sort searches for sub-tev hadronic resonances with the atlas detector
topic Particle Physics - Experiment
url http://cds.cern.ch/record/2258823
work_keys_str_mv AT krizkakarol searchesforsubtevhadronicresonanceswiththeatlasdetector