Bin Norisam, Raif Rafideen;
(2025)
Search for Resonant Production from HH → bb ̄bb ̄ Final states in ATLAS Detector using Boosted and Superboosted Analysis.
Doctoral thesis (Ph.D), UCL (University College London).
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Abstract
This thesis presents a search for resonant Higgs boson pair production in the HH → b¯bb¯b final state via gluon-gluon fusion (ggF), using 139 fb−1 of ATLAS Run-2 data. The analysis is performed using two reconstruction strategies: the Boosted and Superboosted approaches. The primary objective is to search for new resonances (X_R) predicted by Beyond the Standard Model (BSM) theories, decaying into pairs of Higgs bosons. Two benchmark BSM theories are considered: excited massive Kaluza–Klein gravitons from the Randall–Sundrum model and heavy neutral scalar bosons from the Two-Higgs-Doublet Model (2HDM), both of which offer potential solutions to the hierarchy problem in the Standard Model (SM). The resonant HH searches in the HH → b¯bb¯b channel are organized into three reconstruction strategies: Resolved, Boosted, and Superboosted. The Resolved strategy targets Higgs boson pairs with mild to intermediate Lorentz boosts, cov- ering resonance masses in the range 251–1600 GeV. The Boosted strategy focuses on intermediate to high-boost Higgs boson pairs, probing masses between 900–5000 GeV. The Superboosted strategy, newly developed for this work, is designed for extremely high-boost Higgs boson pairs, with sensitivity to resonance masses in the 1600–5000 GeV range. The sensitivity to the process σ (pp → XR → HH → b¯bb¯b) is evaluated using the Boosted and Superboosted strategies with 139 fb−1 of data. Results are expressed in terms of 95% confidence level (CL) upper limits on the production cross-section as a function of resonance mass. No significant excess is observed, and 95% CL upper limits are established. The combination of the Resolved and Boosted strategies reveals no significant deviation from SM predictions.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | Ph.D |
| Title: | Search for Resonant Production from HH → bb ̄bb ̄ Final states in ATLAS Detector using Boosted and Superboosted Analysis |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Copyright © The Author 2025. Original content in this thesis is licensed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International (CC BY-NC 4.0) Licence (https://creativecommons.org/licenses/by-nc/4.0/). Any third-party copyright material present remains the property of its respective owner(s) and is licensed under its existing terms. Access may initially be restricted at the author’s request. |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10209175 |
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