UID:
almahu_9949500735202882
Format:
XV, 193 p. 135 illus., 118 illus. in color.
,
online resource.
Edition:
1st ed. 2023.
ISBN:
9783031304668
Series Statement:
Springer Theses, Recognizing Outstanding Ph.D. Research,
Content:
This work describes a search for exotic decays of the Higgs boson to two long-lived, neutral, spin-0 particles which subsequently decay to pairs of b quarks, giving the striking signature of displaced hadronic jets in the ATLAS inner detector. Several other ATLAS searches have probed this decay topology previously, excluding branching ratios of the Higgs boson to long-lived particles (LLPs) of more than 10% for proper lifetimes greater than 100mm. These searches relied on dedicated triggers designed to select events with LLPs decaying in the ATLAS calorimeter or muon spectrometer. The lack of an equivalent trigger for LLP decays in the ATLAS inner detector has been a limiting factor in probing LLP lifetimes less than 100mm. To circumvent the difficulty of triggering on LLP decays, the search presented in this thesis exploits the ZH associated production mode, relying on leptonic trigger signatures to select interesting events. This is the first search for Higgs boson decays into LLPs to exploit this analysis methodology and additionally makes use of several novel methods for both background rejection and background estimation. No excess over Standard Model predictions is observed, and upper limits are set on the branching ratio of the Higgs boson to LLPs . Depending on the mass of the LLP, branching ratios greater than 10% are excluded for lifetimes as small as 4mm and as large as 100mm, probing an important gap in the ATLAS exotic Higgs decay programme. In comparison to the previous searches for Higgs decays to LLPs, these are among the most stringent limits placed on this scenario, and for LLPs with masses below 40 GeV these results represent the strongest existing constraints on the branching ratio of the Higgs boson to LLPs in this lifetime regime.
Note:
The Standard Model -- Physics Beyond the Standard Model -- The Large Hadron Collider and the ATLAS Detector -- Event Reconstruction -- Reconstruction of Long-Lived Particle Decays.
In:
Springer Nature eBook
Additional Edition:
Printed edition: ISBN 9783031304651
Additional Edition:
Printed edition: ISBN 9783031304675
Additional Edition:
Printed edition: ISBN 9783031304682
Language:
English
DOI:
10.1007/978-3-031-30466-8
URL:
https://doi.org/10.1007/978-3-031-30466-8
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