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Studying Production of Multiple Higgs Bosons at the Large Hadron Collider
Studying Production of Multiple Higgs Bosons at the Large Hadron Collider
상세정보
- 자료유형
- 학위논문 서양
- 최종처리일시
- 20260202103645
- ISBN
- 9798314874714
- DDC
- 530
- 서명/저자
- Studying Production of Multiple Higgs Bosons at the Large Hadron Collider
- 발행사항
- [Sl] : University of Michigan, 2025
- 발행사항
- Ann Arbor : ProQuest Dissertations & Theses, 2025
- 형태사항
- 257 p
- 주기사항
- Source: Dissertations Abstracts International, Volume: 86-11, Section: B.
- 주기사항
- Advisor: Qian, Jianming.
- 학위논문주기
- Thesis (Ph.D.)--University of Michigan, 2025.
- 초록/해제
- 요약The discovery of the Higgs boson (h) in 2012 marked a significant milestone in confirming the Standard Model (SM) as a successful theory. Following this discovery, a key priority of the Large Hadron Collider (LHC) research program is to determine whether the properties of this narrow 125 GeV particle align with SM expectations or if it could be a gateway to physics beyond the Standard Model (BSM). Studying the simultaneous production of two or more Higgs bosons can provide key insights into these questions. This dissertation presents two searches for rare Standard Model processes resulting from proton-proton collisions at a center-of-mass energy of 13 TeV, using data collected with the ATLAS detector at CERN's LHC from 2015 to 2018. The first search investigates Higgs boson pair production (hh) produced in association with a vector boson V (W or Z). Leptonic decays of the vector boson are targeted, with both Higgs bosons decaying to b-quark pairs, resulting in three unique final states based on the number of leptons. The Vhh process involving both SM-like non-resonant and BSM-motivated resonant hh production are explored. Resonant hh production is examined within the context of a neutral heavy scalar resonance H that decays to hh (VH), and a resonant pseudoscalar A boson that decays into a Z and H boson (A → ZH). Upper limits are placed on SM-like non-resonant Vhh production, and constraints are derived on the Higgs boson tri-linear self-coupling and quartic-gauge coupling constants. Upper limits on resonant Higgs trahlung Vhh production cross-section are placed for an H mass in the range of 260-1000 GeV, and for A → ZH production for a scalar A mass in the range of 360-800 GeV with an H boson mass of 260-400 GeV. Overall, a slight excess of observed data over the SM background results in weaker observed constraints than expected. Constraints on A → ZH production are also interpreted in the context of the Two-Higgs-Doublet Model. The second is a search for triple-Higgs boson production (hhh) in the 6 b-quark final state, exploring both SM-like non-resonant and BSM-motivated resonant production. The non-resonant search uniquely constrains hhh production as a function of the trilinear and quartic self-coupling constants. The resonant cascade process X → Sh → hhh is considered primarily, where X and S are two new heavy scalars with masses of up to 1.5 and 1 TeV, respectively. Central to this analysis is the background estimation in the 6b final-state, which is dominated by QCD multi-jet processes. A novel, fully data-driven approach is employed, which features an extrapolation from a lower b-tag to a higher b-tag multiplicity region. In all interpretations, no evidence for hhh production is observed. Upper limits on the hhh production cross-sections are placed at the 95% confidence level and constraints on the trilinear and quartic self-couplings are derived. An upper limit for the Standard Model hhh production cross-section is set at 59 fb at a 95% confidence level.
- 일반주제명
- Physics
- 일반주제명
- Particle physics
- 일반주제명
- Theoretical physics
- 키워드
- Atlas experiment
- 키워드
- Leptons
- 기타저자
- University of Michigan Physics
- 기본자료저록
- Dissertations Abstracts International. 86-11B.
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
MARC
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■00520260202103645
■006m o d
■007cr#unu||||||||
■020 ▼a9798314874714
■035 ▼a(MiAaPQ)AAI32092610
■035 ▼a(MiAaPQ)umichrackham006127
■040 ▼aMiAaPQ▼cMiAaPQ
■0820 ▼a530
■1001 ▼aKyriacou, Nicholas Graves.
■24510▼aStudying Production of Multiple Higgs Bosons at the Large Hadron Collider
■260 ▼a[Sl]▼bUniversity of Michigan▼c2025
■260 1▼aAnn Arbor▼bProQuest Dissertations & Theses▼c2025
■300 ▼a257 p
■500 ▼aSource: Dissertations Abstracts International, Volume: 86-11, Section: B.
■500 ▼aAdvisor: Qian, Jianming.
■5021 ▼aThesis (Ph.D.)--University of Michigan, 2025.
■520 ▼aThe discovery of the Higgs boson (h) in 2012 marked a significant milestone in confirming the Standard Model (SM) as a successful theory. Following this discovery, a key priority of the Large Hadron Collider (LHC) research program is to determine whether the properties of this narrow 125 GeV particle align with SM expectations or if it could be a gateway to physics beyond the Standard Model (BSM). Studying the simultaneous production of two or more Higgs bosons can provide key insights into these questions. This dissertation presents two searches for rare Standard Model processes resulting from proton-proton collisions at a center-of-mass energy of 13 TeV, using data collected with the ATLAS detector at CERN's LHC from 2015 to 2018. The first search investigates Higgs boson pair production (hh) produced in association with a vector boson V (W or Z). Leptonic decays of the vector boson are targeted, with both Higgs bosons decaying to b-quark pairs, resulting in three unique final states based on the number of leptons. The Vhh process involving both SM-like non-resonant and BSM-motivated resonant hh production are explored. Resonant hh production is examined within the context of a neutral heavy scalar resonance H that decays to hh (VH), and a resonant pseudoscalar A boson that decays into a Z and H boson (A → ZH). Upper limits are placed on SM-like non-resonant Vhh production, and constraints are derived on the Higgs boson tri-linear self-coupling and quartic-gauge coupling constants. Upper limits on resonant Higgs trahlung Vhh production cross-section are placed for an H mass in the range of 260-1000 GeV, and for A → ZH production for a scalar A mass in the range of 360-800 GeV with an H boson mass of 260-400 GeV. Overall, a slight excess of observed data over the SM background results in weaker observed constraints than expected. Constraints on A → ZH production are also interpreted in the context of the Two-Higgs-Doublet Model. The second is a search for triple-Higgs boson production (hhh) in the 6 b-quark final state, exploring both SM-like non-resonant and BSM-motivated resonant production. The non-resonant search uniquely constrains hhh production as a function of the trilinear and quartic self-coupling constants. The resonant cascade process X → Sh → hhh is considered primarily, where X and S are two new heavy scalars with masses of up to 1.5 and 1 TeV, respectively. Central to this analysis is the background estimation in the 6b final-state, which is dominated by QCD multi-jet processes. A novel, fully data-driven approach is employed, which features an extrapolation from a lower b-tag to a higher b-tag multiplicity region. In all interpretations, no evidence for hhh production is observed. Upper limits on the hhh production cross-sections are placed at the 95% confidence level and constraints on the trilinear and quartic self-couplings are derived. An upper limit for the Standard Model hhh production cross-section is set at 59 fb at a 95% confidence level.
■590 ▼aSchool code: 0127.
■650 4▼aPhysics
■650 4▼aParticle physics
■650 4▼aTheoretical physics
■653 ▼aAtlas experiment
■653 ▼aLarge Hadron Collider
■653 ▼aLeptons
■653 ▼aSelf-coupling constants
■653 ▼aHiggs boson physics
■690 ▼a0605
■690 ▼a0798
■690 ▼a0753
■71020▼aUniversity of Michigan▼bPhysics.
■7730 ▼tDissertations Abstracts International▼g86-11B.
■790 ▼a0127
■791 ▼aPh.D.
■792 ▼a2025
■793 ▼aEnglish
■85640▼uhttp://www.riss.kr/pdu/ddodLink.do?id=T17358106▼nKERIS▼z이 자료의 원문은 한국교육학술정보원에서 제공합니다.
