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Author ORCID Identifier
https://orcid.org/0000-0002-2204-5731
AccessType
Open Access Dissertation
Document Type
dissertation
Degree Name
Doctor of Philosophy (PhD)
Degree Program
Physics
Year Degree Awarded
2023
Month Degree Awarded
September
First Advisor
Verena Martinez Outschoorn
Second Advisor
Rafael Coelho Lopes de Sa
Subject Categories
Elementary Particles and Fields and String Theory
Abstract
The discovery of the Higgs boson has opened up new possibilities for investigating physics beyond the Standard Model (SM). New particles may interact with the SM through the Higgs boson, and deviations from SM predictions can indicate the presence of new physics. This dissertation focuses on the search for exotic Higgs decay, $H\rightarrow aa \rightarrow (b\bbar)(b\bbar)$ where a is a new scalar boson and focuses on the case where the Higgs boson is produced in association with a Z boson. The data were collected by the ATLAS detector at the Large Hadron Collider at center-of-mass energy $\sqrt{s} =~13~\TeV$ from 2015 to 2018 with a total integrated luminosity of 140 fb^{-1}. A new general-purpose low-mass double-b tagging algorithm was developed and applied in the search. With new machine-learning reconstruction techniques, the search is able to set a strong limit on the branching ratio of Br($H\rightarrow aa \rightarrow (b\bbar)(b\bbar)$). Furthermore, the search also considers models with two new scalars of different masses, $a_{1}$ and $a_{2}$, and sets the limits on the branching ratio of Br($H\rightarrow a_{1}a_{2} \rightarrow (b\bbar)(b\bbar)$)
DOI
https://doi.org/10.7275/35921565
Recommended Citation
Chou, Yuan-Tang, "Search for exotic Higgs boson decay to multiple b-quarks with the ATLAS detector at LHC using machine learning methods" (2023). Doctoral Dissertations. 2972.
https://doi.org/10.7275/35921565
https://scholarworks.umass.edu/dissertations_2/2972