Dissertation
Evidence of the Standard Model Higgs boson decaying to two muons
University of Iowa
Doctor of Philosophy (PhD), University of Iowa
Summer 2021
DOI: 10.17077/etd.005845
Abstract
Previous measurements at CMS and ATLAS observed the Higgs boson coupling to third generation fermions. The study of the Higgs boson decaying to two muons extends the investigation to its coupling to second generation fermions. A search for the Standard Model Higgs boson decaying into a pair of oppositely charged muons is presented. The search uses proton-proton collision data at sqrt(s)=13 TeV recorded by the CMS experiment at the CERN LHC in 2016, 2017, and 2018, corresponding to an integrated luminosity of 137.2 fb^-1. Combined with the CMS Run 1 results, the observed (expected) significance over the background only expectation for a 125.38 GeV Higgs boson is 3.0 (2.5). This result constitutes the first experimental evidence for the Higgs boson decaying to a pair of muons. An upgrade to the CMS Outer Tracker in preparation for the HL-LHC, and improvements to the CMS forward Hadron Calorimeter are also presented.
Details
- Title: Subtitle
- Evidence of the Standard Model Higgs boson decaying to two muons
- Creators
- Mohammad Alhusseini
- Contributors
- Yasar Onel (Advisor)Jane Nachtman (Committee Member)Wayne Polyzou (Committee Member)Mary Hall Reno (Committee Member)Leonard Spiegel (Committee Member)
- Resource Type
- Dissertation
- Degree Awarded
- Doctor of Philosophy (PhD), University of Iowa
- Degree in
- Physics
- Date degree season
- Summer 2021
- DOI
- 10.17077/etd.005845
- Publisher
- University of Iowa
- Number of pages
- xix, 111 pages
- Copyright
- Copyright 2021 Mohammad Alhusseini
- Language
- English
- Description illustrations
- color illustrations
- Description bibliographic
- Includes bibliographical references (pages 93-99).
- Public Abstract (ETD)
The Standard Model of particle physics aims to list the elementary particles and explain the forces that govern them. An important characteristic of all elementary particles, which some people take for granted, is their mass. While most people learn the mass of the electron in their chemistry class and believe the photon to be massless, only a few question how this property comes to be.
The Standard Model is able to explain why particles like the electron have mass, and why photons are massless. The Standard Model theory explains this through the Higgs mechanism, and predicts the mechanism to be mediated by a particle called the Higgs boson. The Higgs mechanism and Higgs boson are somewhat analogous to the electromagnetic force and its mediator, the photon.
In order to test the Standard Model theory, a particle collider was built at CERN in Geneva, Switzerland. This collider, called the LHC, collides protons together to produce highly energetic and massive particles, such as the Higgs boson. Through this research, the LHC collisions are studied using data collected by the CMS experiment, and a search for the Higgs boson is undergone. More specifically, we look for the specific interaction of the Higgs boson with another elementary particle, the muon, which can be thought of as a heavier version of the electron. Our results give us the first experimental evidence that the Higgs boson interacts with the muon as theorized by the Standard Model.
- Academic Unit
- Physics and Astronomy
- Record Identifier
- 9984124471102771
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