Degree Date: May, 2019
Salvatore Aiola's picture
Salvatore Aiola
John Harris

Jet and heavy-flavor measurements in pp and Pb–Pb collisions with ALICE

Quantum Chromo-Dynamics (QCD) is the field theory that describes the nuclear interactions, responsible for holding together quarks and gluons inside the atomic nuclei. Despite significant progress made in over four decades of experimental and theoretical work since QCD was established, there remain many open questions, especially regarding the fragmentation process of quarks and gluons and the behavior of QCD in the high-temperature regime. Jets are produced from hard-scattered quarks and... more
James Mulligan's picture
James Mulligan
John Harris

Inclusive jet measurements in Pb-Pb collisions with ALICE

Droplets of deconfined quarks and gluons, known as the quark-gluon plasma, are produced experimentally in ultrarelativistic heavy-ion collisions. Studying this deconfined matter may allow insight into a variety of open questions about the high temperature regime of QCD and the emergent behaviors of QCD. One major effort to probe the quark-gluon plasma is the study of high-momentum jets produced in an initial high momentum-transfer scattering of a heavy-ion collision. Measurements have... more
Michela Paganini's picture
Michela Paganini
Paul Tipton

Machine Learning in High Energy Physics: Applications to Electromagnic Shower Generation, Flavor Tagging, and the Search for di-Higgs Production

This thesis demonstrate the efficacy of designing and developing machine learning algorithms to selected use cases that encompass many of the outstanding challenges in the field of experimental high energy physics. Although simple implementations of neural networks and boosted decision trees have been used in high energy physics for a long time, the field of machine learning has quickly evolved by devising more complex, fast and stable implementations of learning algorithms. The complexity... more
William Clarke Smith's picture
William Clarke Smith
Michel Devoret

Design of Protected Superconducting Qubits

Controllable quantum systems that are shielded at a Hamiltonian level from the random fluctuations of their environments could provide a valuable resource for quantum information science. While these "protected qubits" promise unprecedentedly low error rates, this might come at the expense of ease of physical implementation. This thesis focuses on overcoming this apparent design problem in protected qubits within the context of superconducting circuits and their quantized... more
Lucie Tvrznikova's picture
Lucie Tvrznikova
Daniel McKinsey

Sub-GeV dark matter searches and electric field studies for the LUX and LZ experiments

Abundant evidence from cosmological and astrophysical observations suggests that the Standard Model does not describe 84% of the matter in our universe. The nature of this dark matter (DM) remains a mystery since it has so far eluded detection in the laboratory. To that end, the Large Underground Xenon (LUX) experiment was built to directly observe the interaction of DM with xenon target nuclei. LUX acquired data from April 2013 to May 2016 at the Sanford Underground Research Facility (SURF) in... more
Degree Date: December, 2018
Elizabeth Boulton's picture
Elizabeth Boulton
Daniel McKinsey

Applications of Two-Phase Xenon Time Projection Chambers: Searching for Dark Matter and Special Nuclear Materials

Over the past four decays, Liquid xenon has emerged as a popular medium for direct detection of dark matter. The Large Underground Xenon (LUX) experiment utilized a 300 kg two-phase xenon detector to set a world-leading limit on the WIMP spin-independent cross-section and WIMP mass parameter space with 332 live-days of data collection. This analysis proved especially challenging due to non-uniform, time-evolving drift fields during the WIMP search run, and it required the use of novel... more
Andrew Gasbarro's picture
Andrew Gasbarro
George Fleming

Studies of Conformal Behavior in Strongly Interacting Quantum Field Theories

In this dissertation, we present work towards characterizing various conformal and nearly-conformal quantum field theories nonperturbatively using a combination of numerical and analytical techniques. A key area of interest is the conformal window of four-dimensional gauge theories with Dirac fermions and its potential application to BSM model building. We advocate a research program in which the generic low energy physics of nearly-conformal gauge theories is characterized by combining... more
Elena Gramellini's picture
Elena Gramellini
Bonnie Fleming

Measurement of the negative pion and positive kaon total hadronic cross sections on argon at the LArIAT experiment

The Liquid Argon Time Projection Chamber (LArTPC) represents one of the most advanced experimental technologies for physics at the Intensity Frontier due to its full 3D-imaging, excellent particle identification and precise calorimetric energy reconstruction. By deploying a LArTPC in a dedicated calibration test beam line at Fermilab, LArIAT (Liquid Argon In A Testbeam) aims to experimentally calibrate this technology in a controlled environment and to provide physics results key to the... more
Junjiajia Long's picture
Junjiajia Long
Thierry Emonet

From Individual to Collective Behavior: The Role of Memory and Diversity in Bacterial Navigation

What is the best strategy to search in an unknown environment? Navigation with only local information available is a ubiquitous problem in nature, especially when local directional information is unreliable due to limited detection range and accuracy. Facing this challenge, many natural systems, including the chemotactic bacteria Escherichia coli, navigate by registering past information “in memory” and making temporal comparisons to bias their random walk up gradients of signal. In... more
Siddharth Prabhu's picture
Siddharth Prabhu
Walter Goldberger

Gluon and Graviton Radiation from the Classical Double Copy

Motivated by the BCJ double copy in quantum field theory, we demonstrate a correspondence between perturbative solutions of classical scalar, gauge and gravity theories. First, we show that classical Yang-Mills radiation from a system of colored particles can be obtained from classical bi-adjoint scalar radiation emitted by a corresponding system of bi-adjoint colored particles, via a simple set of color-kinematic substitution rules. This completes a two-fold double copy that can be used to... more
Jared Vasquez's picture
Jared Vasquez
Paul Tipton

Illuminating the Higgs boson: Measurement of the properties of the Higgs boson in the diphoton channel

This thesis presents results for measurements of the Standard Model Higgs boson properties and production as measured in the diphoton decay channel using 36.1/fb of proton–proton collision data collected at √s = 13 TeV by the ATLAS detector in 2015 and 2016. All the measurements are performed under the assumption that the Higgs boson mass is 125.09 GeV and are compared to Standard Model predictions. No significant deviations of the measurements to the Standard Model predictions are... more
Fangzhou Zhu's picture
Fangzhou Zhu
Nikhil Padmanabhan

Information Mining in the Large Scale Structure of the universe

The Baryon Acoustic Oscillations signal has been an important tool to study the properties of dark energy. Designing efficient and robust data analysis methods that optimize the extraction of information is crucial to realize the immense potential of current and future galaxy surveys. To achieve this goal, this thesis presents the development and implementation of the 'redshift weighting' (Zhu et al 2015, 2016) and 'BAO emulation', two techniques that promise to increase the... more
Degree Date: May, 2018
Jeremy Cushman's picture
Jeremy Cushman
Karsten Heeger

A search for neutrinoless double-beta decay in tellurium-130 with CUORE

The Cryogenic Underground Observatory for Rare Events (CUORE) is a ton-scale cryogenic experiment designed to search for neutrinoless double-beta decay in tellurium-130. The experiment consists of 988 ultracold tellurium dioxide bolometric crystals, which act as both the double-beta decay sources and detectors, in a close-packed configuration. This dissertation presents a search for neutrinoless double double-beta decay with the first two months of CUORE data. An observation of this decay would... more
Stefan Elrington's picture
Stefan Elrington
Sean Barrett

Developing new approaches to faster, high-spatial resolution Phosphorus-31 MR imaging of Bone

Magnetic resonance imaging (MRI) is the leading non-invasive imaging technique of soft tissues on anatomical and millimeter scales. In conventional MRI, hydrogen-1 in water and liquid fats are detected; the relatively narrow spectra of these signals are the key feature that enables MR imaging with high-spatial resolution (i.e., sub-mm in each dimension). The broad NMR spectra of solids would be much more difficult to use in MRI, and would ordinarily result in a low spatial resolution image.... more
Yvonne Gao's picture
Yvonne Gao
Robert Schoelkopf

Multi-cavity Operations in Circuit Quantum Electrodynamics

The eventual success of a quantum computer relies on our ability to robustly initialise, manipulate, and measure quantum bits in presence of the inevitable occurrence of errors. This requires us to encode quantum information redundantly in systems that are suitable for Quantum Error Correction (QEC). One promising implementation is to use three dimensional (3D) superconducting microwave cavities coupled to one or more non-linear ancillae in the circuit quantum electrodynamics (cQED) framework.... more