Title Information
Title
Inclusive Search for a Lorentz-Boosted Higgs Boson Decaying into Bottom Quarks
Name: Personal
Name Part
Kwok, Ka Hei Martin
Role
Role Term: Text
creator
Name: Personal
Name Part
Landsber, Greg
Role
Role Term: Text
Advisor
Name: Personal
Name Part
Fan, Jiji
Role
Role Term: Text
Reader
Name: Personal
Name Part
Cutts, David
Role
Role Term: Text
Reader
Name: Corporate
Name Part
Brown University. Department of Physics
Role
Role Term: Text
sponsor
Origin Information
Copyright Date
2020
Physical Description
Extent
xxxviii, 231 p.
digitalOrigin
born digital
Note: thesis
Thesis (Ph. D.)--Brown University, 2020
Genre (aat)
theses
Abstract
Since the discovery of the Higgs boson in 2012, significant efforts have been put into establishing its coupling to fermions, which is an essential feature of the Higgs boson in the standard model of particle physics. Although the Higgs boson has the largest branching fraction for a decay into bottom quarks, the measurements in this decay mode have to rely on associated production with vector bosons to overcome the overwhelming QCD jet backgrounds. This thesis presents a novel approach that searches for inclusive $\mathrm{H}\to\mathrm{b}\overline{\mathrm{b}}$ decays using jet substructure variables and a b tagging technique based on a deep neural network. This approach explores Higgs boson production at high transverse momentum, which is a complementary phase space region to that in conventional measurements. Results are compared with the latest theoretical predictions at full next-to-leading order accuracy, including finite top quark mass effects. The data sample was collected by the CMS experiment at the LHC at $\sqrt{s}=13~\mathrm{TeV}$, and corresponds to an integrated luminosity of $137~\mathrm{fb}^{-1}$. The method is validated with $\mathrm{Z}\to\mathrm{b}\overline{\mathrm{b}}$ decays. For a Higgs boson mass of $125~\mathrm{GeV}$, an excess of events above the expected background is observed (expected) with a local significance of 2.54 (0,71) standard deviations. The corresponding signal strength is measured to be $\mu_\mathrm{H} = 3.68 \pm 1.20(\mathrm{stat})_{-0.66}^{+0.63}(\mathrm{syst})_{-0.46}^{+0.81}(\mathrm{thy})$ with respect to the standard model predictions. Additionally, an unfolded differential cross section, as a function of the Higgs boson transverse momentum is presented.
Subject
Topic
LHC
Subject
Topic
CMS Experiment
Subject (fast) (authorityURI="http://id.worldcat.org/fast", valueURI="http://id.worldcat.org/fast/00955984")
Topic
Higgs bosons
Subject
Topic
btagging
Language
Language Term (ISO639-2B)
English
Record Information
Record Content Source (marcorg)
RPB
Record Creation Date (encoding="iso8601")
20210607
Type of Resource (primo)
dissertations