• Search for dark matter produced in association with a Z boson in the ATLAS detector at the Large Hadron Collider 

  McLean, Kayla Dawn (2021-03-01)

  This dissertation presents a search for dark matter particles produced in association with a Z boson in proton-proton collisions. The dataset consists of 139 fb^{-1} of collision events with centre-of-mass energy of 13 ...
• Mass assembly in star formation via interstellar filaments 

  Chen, Michael Chun-Yuan (2021-01-28)

  Understanding how diffuse molecular clouds at large scales (~10 pc) assemble mass into dense, star-forming cores at small scales (~ 0.1 pc) is crucial to building a holistic theory of star formation. While recent observations ...
• The first stars and the convective-reactive regime 

  Clarkson, Ondrea (2021-01-11)

  Due to their initially metal-free composition, the fi rst stars in the Universe, which are termed Population III (Pop III) stars, were fundamentally different than later generations of stars. As of now, we have yet to ...
• Chemo-dynamics of newly discovered metal-poor stars and improved spectroscopic tools 

  Kielty, Collin Louis (2021-01-07)

  This dissertation presents two chemo-dynamical analyses of metal-poor stars found within the Milky Way. 115 metal-poor candidate stars, including 28 confirmed very metal-poor stars, selected from the narrow-band Pristine ...
• Search for Higgs boson decays to beyond-the-Standard-Model light bosons in four-lepton events with the ATLAS detector at the LHC 

  Chiu, Justin (2020-12-22)

  This thesis presents the search for the dark sector process h -> Zd Zd -> 4l in events collected by the ATLAS detector at the Large Hadron Collider in 2015--2018. In this theorized process, the Standard Model Higgs boson ...
• Dynamics of gas and dust in protoplanetary disks: planet formation from observational and numerical perspectives 

  Bi, Jiaqing (2020-12-21)

  Dust and gas in protoplanetary disks are the building blocks of planets. In this thesis, we study the dynamics of the gas and dust, which are crucial for the planet formation theory, using observational and numerical ...
• Fossils of the distant Galaxy: NGC 5466 and its stellar stream 

  Jensen, Jaclyn (2020-12-07)

  The stellar halo of the Milky Way is populated by mostly old and metal-poor stars. As dynamical timescales are of order ~Gyrs at these large distances, accreted stellar substructures, such as dwarf galaxies or globular ...
• Studying a fire from its ashes: white dwarfs as probes of Milky Way evolution 

  Fantin, Nicholas J. (2020-12-01)

  As the remnants of stars with initial masses < 8 M⊙, white dwarfs contain valuable information regarding the formation histories of stellar populations. This dissertation focuses on using white dwarfs as tracers of Galactic ...
• Contrast agent imaging using an optimized table-top x-ray fluorescence and photon-counting computed tomography imaging system 

  Dunning, Chelsea Amanda Saffron (2020-11-04)

  Contrast agents are often crucial in medical imaging for disease diagnosis. Novel contrast agents, such as gold nanoparticles (AuNPs) and lanthanides, are being ex- plored for a variety of clinical applications. Preclinical ...
• Magnetic excitations of finite systems: edge effects on spin waves 

  Beairsto, Seamus (2020-09-25)

  This thesis explores finite-size effects on the spin-wave excitations of one-dimensional ferromagnetic and antiferromagnetic systems. Specifically, it presents a theoretical study of the scattering function, the physical ...
• A deep polarimetric analysis of the debris disk HD 106906 

  Crotts, Katie (2020-08-28)

  HD 106906 is a young, binary stellar system, located at ~103.3 parsecs away in the Lower Centaurus Crux (LCC) group. This system is completely unique among known systems in that it contains an asymmetrical debris disk, as ...
• Hybrid macro-particle moment accelerator tracking algorithm 

  Jung, Paul Matthew (2020-08-27)

  A particle accelerator simulation which straddles the gap between multi-particle and moment codes is derived. The hybrid approach represents the beam using macro-particles which contain discrete longitudinal coordinates and ...
• Probing galaxy evolution through numerical simulations: mergers, gas, and star formation 

  Hani, Maan H. (2020-08-27)

  Large observational surveys have compiled substantial galaxy samples with an array of different properties across cosmic time. While we have a broad understanding of how galaxies grow and build their observable properties, ...
• Does size matter? Exploring the viability of measuring the charge radius of the first excited nuclear state in muonic zirconium 

  Wilkinson-Zan, Benjamin (2020-08-25)

  From the point of view of the electromagnetic interaction, empirical descriptions of the nucleus involve only a few parameters, one of the most important being the nuclear charge radius. This has been well measured for ...
• Constraints effecting stability and causality of charged relativistic hydrodynamics 

  Hoult, Raphael E (2020-08-05)

  First-order viscous relativistic hydrodynamics has long been thought to be unsta- ble and acausal. This is not true; it is only with certain definitions of the hydrody- namic variables that the equations of motion display ...
• Morphological and kinematic indicators of structural transformation in galaxies 

  Bottrell, Connor (2020-08-05)

  The observed properties of galaxies are intricately connected to their respective evolutionary histories. Establishing these connections – tying the morphologies, dynamics, and other properties of galaxies to the dominant ...
• Theoretical investigation of size effects in multiferroic nanoparticles 

  Allen, Marc Alexander (2020-08-05)

  Over the last two decades, great progress has been made in the understanding of multiferroic materials, ones where multiple long-range orders simultaneously exist. However, much of the research has focused on bulk systems. ...
• Exoplanet imaging speckle subtraction: current limitations and a path forward 

  Gerard, Benjamin Lionel (2020-05-20)

  The direct detection and detailed characterization of exoplanets using extreme adaptive optics (ExAO) is a key science case of both current and future telescopes. However, both quasi-static and residual atmospheric wavefront ...
• Cosmological constraints on sub-GeV dark vectors 

  Coffey, John (2020-04-21)

  The purpose of this thesis is to recognize the effects of electromagnetic energy injection into the early Universe from decaying sub-GeV dark vectors. Decay widths and energy spectra for the most prominent channels in ...
• A comparison of the effects of local and global environment on galaxy evolution in low redshift galaxy clusters 

  Howard, Brittany (2020-01-03)

  Using the redMaPPer catalog of 21709 galaxy clusters and photometric information for 455946 galaxies from SDSS DR8, we study the effects of local and global environment on galaxy evolution within clusters in the redshift ...

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