Physical Sciences and Mathematics Commons^™

Magnetic Spin Transport Coils For The N2edm Experiment, David C. Bowles

Theses and Dissertations--Physics and Astronomy

The n2EDM experiment is being construct at Paul Scherrer Institute to measure the electric dipole moment of the neutron (nEDM), in a search for new physics which could help explain the baryon asymmetry of the universe. To reach the experimental sensitivity goal of $d_n \sim 10^{-27}$, over an order of magnitude improvement from the current world limit, a spin polarization transfer efficiency of 99\% for ultracold neutrons entering or exiting the precession chamber is required, placing a stringent requirement on the adiabaticity of the magnetic field taper in the neutron guide system. The spin transport fields transition from 5~T (longitudinal) …

Qcd Analysis Of Flavor-Nonchanging Hadronic Weak Processes Through Next-To-Leading Order, Girish Lingadahalli Muralidhara

Theses and Dissertations--Physics and Astronomy

Studies in quantum chromodynamics (QCD), the fundamental theory of the strong interactions, of low-energy hadronic weak processes utilize an effective Hamiltonian framework. Below the weak-mass scale, an effective Hamiltonian contains a series of Wilson coefficients and four-quark operators that come from the operator product expansion in the Standard Model. The effective hadronic Hamiltonian pertinent to a weak process is then obtained via a renormalization group analysis in QCD from the weak-mass scale to the low-energy scale of O(2 GeV). In this thesis, the construction and phenomenological implications of such an effective Hamiltonian for flavor-conserving, parity-violating quark processes in the Standard …

Exploring The Hot And Gaseous Universe From Infrared To X-Ray, Chamani Gunasekera

Theses and Dissertations--Physics and Astronomy

Over 90% of baryonic matter in the universe exists as astrophysical plasmas. The gas
is often far from thermodynamic equilibrium, so numerical non-equilibrium spectral
synthesis simulations are used to understand observations. cloudy simulates vari-
ous physical conditions, providing spectra predictions. This thesis aims to meet the
challenge of new observatories like the JWST (James Webb Space Telescope) and
XRISM (X-Ray Imaging Spectroscopy Mission). These simulations are no better
than the underlying atomic and molecular database and the fourth chapter details
a long-needed update to an evolving database. The predicted spectra are strongly
affected by the composition of the gas, which …

Measurements Of The Binding Energies Of Ions On Plastic Surfaces In Liquid Nitrogen, Ashok Timsina

Theses and Dissertations--Physics and Astronomy

To improve the present limit of the neutron electric dipole moment (nEDM) from 1.8*10^-26 e. cm to ~ 3*10^-28 e. cm, the nEDM@SNS experiment plans to increase neutron density by storing ultracold neutrons in superfluid helium-4. In this experiment, the central part of the apparatus consists of two deuterated tetraphenyl butadiene (dTPB) coated poly(methyl methacrylate) (PMMA) cells, which are sandwiched between grounded and high-voltage electrodes. To achieve such precision, the externally applied electric field has to be stable at the 1% level over a time period of about 1000 s. Several sources of ambient ionizing radiation generate charged …

The Radial Quenching Progression Of Nearby Galaxies, Chenyu Zhao

Theses and Dissertations--Physics and Astronomy

In this dissertation, we explore the spatial distribution of quiescent regions within galaxies using data from the Sloan Digital Sky Survey IV Mapping Nearby Galaxies at Apache Point Observatory (SDSS-IV MaNGA). Our analysis focuses on a radial range spanning from 0.3 R e to 1.2 R e and involves the development of innovative data selection and processing methods. Through this investigation, we identify two prominent types of transition galaxies: central-star-forming galaxies (C-SF galaxies) and central-quiescent galaxies (C-Q galaxies). Notably, we observe a correlation between galaxy mass and the predominant type of transition, with more massive galaxies tending to be C-Q …

Aspects Of Topology In Moiré Graphene, Ahmed Khalifa

Theses and Dissertations--Physics and Astronomy

Moiré materials, such as twisted bilayer graphene, have provided a rich platform for fundamental physics and potential technological applications. Superconductivity,
correlated insulators, and Chern insulators are examples of phenomena that have been found experimentally in moiré systems. The interplay of strong electron-electron interactions and topology lies at the heart of the mechanism driving these phenomena. In this work, we study the topological aspects of moiré graphene materials, such as the valley Chern and Chern insulating phases. To study the topological response of these phases, we construct models to describe the edge states which are the telltale signs of nontrivial topology. …

Symbolic Computation Of Squared Amplitudes In High Energy Physics With Machine Learning, Abdulhakim Alnuqaydan

Theses and Dissertations--Physics and Astronomy

The calculation of particle interaction squared amplitudes is a key step in the calculation of cross sections in high-energy physics. These complex calculations are currently performed using domain-specific symbolic algebra tools, where the computational time escalates rapidly with an increase in the number of loops and final state particles. This dissertation introduces an innovative approach: employing a transformer-based sequence-to-sequence model capable of accurately predicting squared amplitudes of Standard Model processes up to one-loop order when trained on symbolic sequence pairs. The primary objective of this work is to significantly reduce the computational time and, more importantly, develop a model that …

Beam Dynamics Simulations And Systematic Studies For The Muon G-2 Experiment At Fermilab, Abel M. Lorente Campos

Theses and Dissertations--Physics and Astronomy

The first results of the positive muon anomalous magnetic moment from the Muon g-2 Experiment at Fermilab differs from the Standard Model prediction by 3.3 standard deviations, with an experimental uncertainty of 0.46 ppm. Combining this result with the previous measurement from the Brookhaven National Laboratory, it sets the difference between experiment and theory at 4.2 standard deviations. The goal of the Muon g-2 Experiment at Fermilab is to increase this discrepancy to 5 standard deviations, which would require unprecedented precision in the measurements of 0.14 ppm. Of significant importance to achieving this precision, beam and spin dynamics simulations are …

Design Of The Highly Uniform Magnetic Field And Spin-Transport Magnetic Field Coils For The Los Alamos National Lab Neutron Electric Dipole Moment Experiment, Jared Brewington

Theses and Dissertations--Physics and Astronomy

Charge-Parity (CP) violation is one of Sakharov's three conditions which serve as guidelines for the generation of a matter-antimatter asymmetry in the early universe. The Standard Model (SM) of particle physics contains sources of CP violation which can be used to predict the baryon asymmetry. The observed baryon asymmetry is not predicted from SM calculations, meaning there must be additional sources of CP violation beyond the Standard Model (BSM) to generate the asymmetry. Permanent electric dipole moments (EDMs), which are inherently parity- and time reversal- violating, present a promising avenue for the discovery of new sources of CP violation to …

The Design Of Primary Holding Magnet For The Lanl Neutron Electric Dipole Moment Experiment, Piya Amara Palamure

Theses and Dissertations--Physics and Astronomy

The measurement of the permanent electric dipole moment of the neutron (nEDM) plays a significant role in searching for sources of beyond standard model CP violating physics. The goal of the Los Alamos National Laboratory (LANL) nEDM experiment is to push the upper limit of the nEDM to < 3 × 10−27 e·cm (68 % CL). A highly uniform magnetic field is key to achieving this sensitivity for the nEDM measurement by reducing the systematic uncertainties associated with the magnetic field non-uniformity. The B0 coil was designed to achieve a field uniformity of < 0.3 nT·m−1 at a nominal holding field of 1 µT. This document will outline a novel technique employed in the construction of the B0 coil using printed circuit boards (PCBs) and will present preliminary field maps obtained with the B0 coil housed in a magnetically shielded room (MSR) at LANL.

As Ultra Cold Neutrons (UCNs) move from the source to the measurement cells, the UCNs experience a large magnetic field gradient in the region between the layers of the MSR. This large gradient would otherwise cause depolarization of the UCNs. To mitigate this, a double cos θ coil will serve as the …

A Multidimensional View On The Emission-Line Diagnostics Of The Warm Ionized Gas In Nearby Galaxies, Xihan Ji

Theses and Dissertations--Physics and Astronomy

The baryonic cycle, being a fundamental process that shapes the cosmic ecosystem, describes the transformation and migration of baryonic matter in different phases. The warm ionized interstellar medium (ISM), defined as low-density gas that has temperature of the order of 10,000 K, represents an important link of the baryonic cycle and can be produced by a variety of energetic activities in galaxies, such as star formations, active galactic nuclei, and so forth. More importantly, the formation and evolution of the warm ionized gas not only traces the ongoing activities of the galaxies, but also reveals the past evolution of galaxies …

Stellar Parameter Determination For The Mastar Stellar Library, Daniel J. Lazarz

Theses and Dissertations--Physics and Astronomy

Empirical libraries of stellar spectra represent a key ingredient needed for modeling the integrated spectra of stellar populations, such as galaxies, through a process called stellar population synthesis (SPS). In order to make use of such libraries, accurate stellar atmospheric parameter estimates are required. Here, I present a methodology that was developed to build a stellar parameter catalog to accompany the MaNGA stellar library (MaStar), a comprehensive collection of empirical, medium-resolution stellar spectra. This parameter catalog was constructed using a multicomponent χ² fitting approach to match the MaStar spectra to models generated by interpolating the ATLAS9-based BOSZ models. The …

Energy Integrated Ratio Analysis Of The Anomalous Precession Frequency In The Fermilab Muon G-2 Experiment, Ritwika Chakraborty

Theses and Dissertations--Physics and Astronomy

The muon’s anomalous magnetic moment, a_μ, provides a unique way for probing physics beyond the standard model experimentally as it gathers contributions from all the known and unknown forces and particles in nature. The theoretical prediction of a_μ has been in greater than 3 σ tension with the experimental measurement since the results of the Muon g-2 Experiment at the Brookhaven National Laboratory (E-821) were published in the early 2000s with a precision of 540 ppb. To settle this tension, the new Fermilab Muon g - 2 Experiment (E-989) is currently taking data with the aim of …

Constraining The Star Formation Histories Of Galaxies In The Swift/Uvot + Manga (Swim) Value-Added Catalog, Nikhil Ajgaonkar

Theses and Dissertations--Physics and Astronomy

Although our understanding about galaxy evolution has improved in the past few
decades, we still do not understand how galaxies suddenly stop forming stars and move towards a quiescent phase. In order to do that, we must derive the Star Formation Histories (SFHs) of galaxies, that trace the change in Star Formation (SF) inside the galaxy over the cosmic timescale. This is achieved by using a set of spatially resolved near-ultraviolet (NUV) and optical spectroscopic images of the galaxies. We generate the Swift/UVOT + MaNGA value added catalog (SwiM VAC; Molina et al., 2020b) which comprises 150 galaxies having a …

Magnetization Dynamics In A Modified Square Artificial Spin Ice, Amrit Kaphle

Theses and Dissertations--Physics and Astronomy

Artificial spin ices are magnetic metamaterials consisting of nanomagnet arrays in a 2-D lattice. Typically, these nanomagnet arrays are binary macrospins that can only be in an up or down state similar to the Ising spins. They have been intensively used to study magnetic frustration and ordering phenomena in a controlled environment. The hexagonal artificial spin ice and square artificial spin ice are among the most heavily studied systems. In this dissertation, we designed a modified square artificial spin ice system by an ordered substitution of a double-segment for a nanomagnet array in the unit cell of square artificial spin …

Neutron Spectroscopy Of The Parity-Violating 0.734 Ev Neutron Resonance In Lanthanum-139 In Preparation For The Noptrex Time Reversal Violation Experiment, Danielle Schaper

Theses and Dissertations--Physics and Astronomy

One of the most outstanding questions in physics is the matter-antimatter asymmetry of the Universe, resulting from excess baryogenesis processes during the early moments of the formation of the Universe. At present, the types of processes needed to explain this matter excess, so-called `CP-violating processes' are known to exist within the present framework of the Standard Model of particle physics. However, decades of research has shown that our understanding of the origin of these processes is incomplete, as we do not presently know of enough sources of CP-violating processes to account for the large baryon asymmetry that we observe. The …

An Energy-Integrated Analysis For Measuring The Anomalous Precession Frequency For The Muon G − 2 Experiment At Fermilab, Laura Kelton

Theses and Dissertations--Physics and Astronomy

In the search for physics beyond the Standard Model, the Muon g − 2 Experiment at Fermilab (E989) will make the most precise measurement of the anomalous magnetic moment of the muon, a_μ. Improvements in precision come from both increased statistics and new techniques to significantly reduce previous systematic uncertainties. The muon a_μ is determined by extracting both the anomalous spin precession frequency, ω_a, and the average magnetic field sampled by the muons, B. Traditionally an energy threshold analysis method which requires reconstruction of decay positrons from the muon decay, μ⁺ → e^{+ …}

Enhancements To Uniformity Of Magnetic Fields At The Sns Nedm Experiment, Ahmad Saftah

Theses and Dissertations--Physics and Astronomy

The nEDM experiment at the Spallation Neutron Source (SNS) aims to increase
experimental sensitivity to hadronic CP violation by nearly two orders of magnitude.To do that the nEDMSNS experiment requires an extremely uniform magnetic field to maintain ³He polarization during transit to the measurement cell. The Magnetic Shield Enclosure (MSE) coil provides the required field. However, the superconducting shield distorts the MSE field.

This thesis discusses a magnetic cloak for the nEDM@SNS experiment that can restore the MSE field uniformity and cos theta coils designed to test the magnetic cloak in the first part. The second part of this …

Extraction Of Deep Inelastic Cross Sections Using A 10.4 Gev Electron Beam And A Polarized Helium-3 Target, Murchhana Roy

Theses and Dissertations--Physics and Astronomy

Experiment E12-06-121 at Jefferson Lab aims to do a precision measurement of the neutron spin structure function g₂ using inclusive inelastic scattering of electrons over a large kinematic range of x and Q². The third moment of the linear combination of the spin structure functions g₁ and g₂, d₂, is one of the cleanest higher twist observables and contains information on quark-gluon correlations. It is connected to the "color polarizability" or "color Lorentz force" of the nucleon. The experimental data taking was successfully conducted in Hall C using a longitudinally polarized electron …

Milky Way Morphology Probed By 6d Astrometric Data From The Gaia Space Telescope, Joshua Taylor Harry

Theses and Dissertations--Physics and Astronomy

At varying height above and below the plane of the Milky Way, I have used astrometric methods to classify stars of different galactic components of the Milky Way - the thin disk, thick disk, and stellar halo. This work complements prior study of Milky Way sub-structure - notably involving number density and/or pairwise correlations - which demonstrate non-steady state effects in the galaxy, such as axial/north-south symmetry breaking or more complex phenomena like the Gaia snail. This has motivated my exploration of stellar population changes with height about the Milky Way mid-plane, and the study of symmetry in such changes …

Cryogenic Magnetic Field Monitoring System In The Sns Neutron Edm Experiment, Umit Hasan Coskun

Theses and Dissertations--Physics and Astronomy

A permanent neutron electric dipole moment (nEDM), d_n, would violate charge-conjugation and parity (CP) symmetry. The neutron electric dipole moment currently has a global limit of d_n < 1.8 x 10^-26 e cm (90% CL). This limit is intended to be improved by two orders of magnitude by the nEDM experiment at the Spallation Neutron Source (SNS nEDM), d_n ~ 10^-28 e cm. The magnetic field non-uniformities within the experimental region must be precisely monitored and managed in order to suppress systematic effects in the experiment caused by magnetic field gradients. The estimation of magnetic field components within …

First Steps In The Small-Scale Structure Formation In The Universe: The Emergence Of Galaxies, Da Bi

Theses and Dissertations--Physics and Astronomy

Galactic morphology in the contemporary universe results from the convergence of a long list of physical processes, not all of them yet fully understood and quantified. The universe exhibits a hierarchical structure: galaxies grow being immersed in dark matter (DM) halos, which in turn are fed by diffuse and filamentary accretion. I use a suite of very high-resolution zoom-in cosmological simulations of galaxies in order to study the assembly of galaxies at high redshifts, z ≥ 2, to quantify the role of environment and of the parent DM halos in this procss. My models have been chosen to lie within …

Elastic And Inelastic Compton Scattering From Deuterium At 61 Mev, Danula Godagama

Theses and Dissertations--Physics and Astronomy

A Compton scattering experiment using deuteron as target nuclei was carried out at the HIγS free electron laser facility at Durham, NC, with the goal of extracting the electromagnetic scalar polarizabilities of the neutron, α_n and β_n. A beam of 61~MeV gamma photons with a narrow energy spread was incident on a liquid deuterium target. The scattered gamma rays were detected at three scattering angles, 55^o, 115^o and 150^o. Backward-scattered gamma rays were detected using two large-volume NaI spectrometers with energy resolution (σ_E/E) better than 2%. The combined effect of …

Angular Distribution Of Electron-Helium Scattering In The Presence Of A 1.17 Ev Laser Field, Brian N. Kim

Theses and Dissertations--Physics and Astronomy

We have measured relative differential cross sections for 350 eV electrons scattered by a helium target in the presence of 1.17 eV photons from an Nd:YAG laser. We report an angular distribution of free-free electrons that were scattered elastically at angles between 15^o and 80^o and of free-free electrons that underwent the process of electron-impact excitation of helium to its unresolved (1s2s)¹S and (1s2p)¹P excited states at angles between 1^o and 80^o. Our experiments test the momentum transfer dependence and the relationship between elastic and inelastic scattering in the Kroll-Watson approximation. …

Understanding The Physics Of Galaxy Clusters Out To Their Virial Radii And Beyond, Arnab Sarkar

Theses and Dissertations--Physics and Astronomy

In the hierarchical structure formation model, galaxy clusters grow and evolve via mergers and accretion from the surrounding cosmic web, leaving distinctive marks in the gas properties, metallicity, and dynamical state at the outskirts of clusters, which needs to be probed to better understand the growth of a cluster. I probed the gas properties of four nearby galaxy groups MKW4, Antlia, RXJ1159, and ESO3060170 out to their virial radii using deep Suzaku and mostly snapshot Chandra observations. I found the gas entropy profiles of MKW4 follow a power-law at its outskirts - as expected from purely gravitational structure formation model. …

Thermalization And Quantum Information In Conformal Field Theory, Ashish Kakkar

Theses and Dissertations--Physics and Astronomy

The consequences of the constraints of conformal symmetry are far-reaching within
theoretical physics. In this dissertation we address a series of questions in conformal
field theory: 1) We calculate the spectrum of qKdV charges in a large central charge
expansion. 2) We determine the corrections to bulk information geometry from 1/N
contributions to holographic correlators. 3) We study the higher genus partitions
functions of CFTs associated with classical and quantum error-correcting codes.

Studies Of Time Variations Of The Magnetic Field In The Nedm@Sns Experiment, Mojtaba Behzadipour

Theses and Dissertations--Physics and Astronomy

It is thought that equal quantities of matter and antimatter were generated at the moment of the Big Bang. However, observations of the Universe show that there is a significant excess of matter over antimatter. The matter-antimatter asymmetry in the Universe (baryon to photon ratio) is observed to be of the order of 10^-10 [1]. Baryogenesis is a possible explanation for the matter-antimatter asymmetry of the universe. In 1967, Sakharov proposed three criteria necessary for Baryogenesis. The three conditions are: 1) baryon number violation, 2) C and CP violation and 3) departure from thermal equilibrium. However, the Standard Model's …

High Performance Data Acquisition And Analysis Routines For The Nab Experiment, David Mathews

Theses and Dissertations--Physics and Astronomy

Probes of the Standard Model of particle physics are pushing further and further into the so-called “precision frontier”. In order to reach the precision goals of these experiments, a combination of elegant experimental design and robust data acquisition and analysis is required. Two experiments that embody this philosophy are the Nab and Calcium-45 experiments. These experiments are probing the understanding of the weak interaction by examining the beta decay of the free neutron and Calcium-45 respectively. They both aim to measure correlation parameters in the neutron beta decay alphabet, a and b. The parameter a, the electron-neutrino correlation coefficient, is …

Data Acquisition, Analysis And Simulations For The Fermilab Muon G−2 Experiment, Fang Han

Theses and Dissertations--Physics and Astronomy

The goal of the new Muon g-2 E989 experiment at Fermi National Accelerator Laboratory (FNAL) is a precise measurement of the muon anomalous magnetic moment, a_μ ≡ (g-2)/2. The previous BNL experiment measured the anomaly a_μ(BNL) with an uncertainty of 0.54 parts per million (ppm). The discrepancy between the current standard model calculation of the a_μ(SM) and the previous measurement a_μ(BNL) is over 3σ. The FNAL Muon g-2 experiment aims at increasing the precision to 140 parts per billion (ppb) to resolve the discrepancy between the theoretical …

Understanding The Degradation Mechanism In Methyl Ammonium Lead Halide Perovskite And Black Phosphorene Via Electrical Transport Study, Huda Saleh Aljeailan

Theses and Dissertations--Physics and Astronomy

This work seeks to understand the degradation mechanism of technically important material systems such as black phosphorene (BP), arsenic phosphorene (AsP) and Methyl ammonium lead iodide (CH₃NH₃PbI₃) perovskite. Degradation studies were conducted by studying the in-situ electrical transport properties (resistance and thermoelectric power (TEP)) of these materials in vacuum (under annealed condition) and after exposure to the ambient air.

BP and both exhibited p-type semiconducting (positive TEP) behavior under annealed conditions and the changes in their transport properties upon exposure to ambient air can be explained as due to the charge transfer between the …