Type

Text

Type

Dissertation

Advisor

Essig, Rouven | Hobbs, John | Kiryluk, Joanna | Bishai, Mary

Date

2017-12-01

Keywords

associated production | Particle physics | ATLAS | Physics | bottom pair production | higgs boson | particle physics | vector boson

Department

Department of Physics

Language

en_US

Source

This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.

Identifier

http://hdl.handle.net/11401/78288

Publisher

The Graduate School, Stony Brook University: Stony Brook, NY.

Format

application/pdf

Abstract

A Higgs boson has been found in multiple decay modes, but not yet in the mode with the largest standard model (SM) branching fraction: $h\rightarrow b\bar{b}$. This thesis details a search for the SM Higgs when produced with an associated $W$ boson. This search is performed with the ATLAS detector using data from Run 2 of the Large Hadron Collider operating at a center-of-mass energy of 13 TeV and corresponding to an integrated luminosity of 36.1 $fb^{-1}$. The final state of the $W$ boson is its leptonic decay with an electron or muon. The measured signal strength relative to the SM Higgs prediction is $\mu = 1.35^{+0.40}_{-0.39}$(stat.)$^{+0.56}_{-0.47}$(syst.) and the probability that observed data arises from a background fluctuation only gives a gaussian equivalent of 2.30 standard deviations compared to the expected value of 1.80 standard deviations. Combined with additional leptonic modes of associated vector boson production with a $Z$ boson, the significance of $H\rightarrow b\bar{b}$ is observed at 3.5 standard deviations compared to an expected 3.0 standard deviations with a signal strength of $\mu = 1.20^{+0.24}_{-0.23}$(stat.)$^{+0.34}_{-0.28}$(syst.) The combined search demonstrates evidence for both the Higgs boson's decay to $b$-quarks and for its production in association with a vector boson. | 153 pages

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