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Author ORCID Identifier
https://orcid.org/0000-0002-4690-0528
AccessType
Open Access Dissertation
Document Type
dissertation
Degree Name
Doctor of Philosophy (PhD)
Degree Program
Physics
Year Degree Awarded
2021
Month Degree Awarded
September
First Advisor
Ben Brau
Second Advisor
Carlo Dallapiccola
Third Advisor
Jordy de Vries
Fourth Advisor
Alexandra Pope
Subject Categories
Elementary Particles and Fields and String Theory
Abstract
A novel search for exotic decays of the Higgs boson to pairs of long-lived neutral particles, each decaying to a bottom quark pair, is performed using 139 fb-1 of sqrt{s} = 13 TeV proton-proton collision data collected with the ATLAS detector at the LHC. Events consistent with the production of a Higgs boson in association with a leptonically-decaying Z boson are analyzed. Long-lived particle (LLP) decays are reconstructed from inner detector tracks as displaced vertices with high mass and track multiplicity relative to Standard Model processes. The analysis selection requires the presence of at least two displaced vertices, effectively suppressing Standard Model backgrounds. The residual background contribution is estimated using a data driven technique. No excess over Standard Model predictions is observed, therefore upper limits are set on the branching ratio of the Higgs boson to LLPs. Branching ratios of 10% are excluded for LLP mean proper lifetimes as small as 4 mm and as large as 110 mm. For LLP masses below 40 GeV, these results represent the most stringent constraint in this lifetime regime.
DOI
https://doi.org/10.7275/24060127
Recommended Citation
Burzynski, Jackson, "A Search for Exotic Higgs Decays or: How I Learned to Stop Worrying and Love Long-lived Particles" (2021). Doctoral Dissertations. 2279.
https://doi.org/10.7275/24060127
https://scholarworks.umass.edu/dissertations_2/2279
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.