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Beam-Spin Asymmetry Of Exclusive Coherent Electroproduction Of The Π0 Off 4he, Frank Thanh Cao

Doctoral Dissertations

To understand the partonic structure of nucleons in nuclei, measuring the beam spin asymmetry (BSA) from exclusive processes is important to get at the so-called Generalized Parton Distributions (GPDs) that describe the partons’ behavior inside the nucleon. In particular, BSA in Deeply Virtual Meson Production (DVMP) can offer valuable constraints on the transverse GPDs which are not accessible with other exclusive processes. Furthermore, DVMP measurements on bound nucleons can offer insights into structure modification due to the nuclear environment.

The interpretation of this bounded nucleon DVMP on nuclear targets rests on the assumption of factorization and that higher-order effects are …

D-Terms In Bosonic And Fermionic Systems, Jonathan Hudson

Doctoral Dissertations

The most fundamental information about a particle is contained in the matrix elements of its energy-momentum tensor (EMT): the mass and spin. But the EMT contains more information than that. Equally important yet far less known is the D-term and with it, the information contained in the spatial components of the EMT. The D-term and the spatial components of the EMT show in detail how the strong forces inside the nucleon balance to form a bound state and provides unique insights on the nucleon structure. The goal of this thesis is to contribute to a better understanding of the physics …

Electric Form Factor Of The Neutron From Asymmetry Measurements, Richard Frederick Obrecht Jr

Doctoral Dissertations

The overwhelming majority of visible mass in the universe is composed of protons and neutrons, collectively known as nucleons, which are arguably the most important strongly interacting systems to study. A nucleon may naively be thought of as a composite object built out of three non-interacting sub-objects, known as quarks, in the large energy limit; however, the structure of the nucleon is much more complicated, and consequently far richer, than a simple valence-quark picture. There are sea quarks in addition to valence quarks that interact strongly via the exchange of gluons resulting in a complex vacuum structure, and the collective …

Detecting Conceptual Change With Latent Transition Analysis, Glen Davenport

Doctoral Dissertations

To uphold the core premise of cognitive diagnostic assessment, it is necessary to align different aspects of assessment design. The structure of the test, the measurement model, and the score reporting must align with each other and with the construct being targeted. Conceptual knowledge, as targeted by the Force and Motion Conceptual Evaluation (FMCE), can be modeled as a set of overlapping categorical states. As such, latent class analysis (LCA) is the most appropriate measurement model—where students have a probabilistic membership within classes that tend to match with observed mental models.

This dissertation focuses on one particular application of conceptual …

Molecular Ionization From The Ground And Excited States Of I2 By Intense Laser Fields, Hui Chen

Doctoral Dissertations

Exposing molecules to strong laser fields produces a variety of effects, which has led to considerable work in many areas, such as enhanced ionization, high harmonic generation, nonsequential double ionization, and coherent control. However, these strong-field experiments start with neutral ground-state molecules at their equilibrium internuclear separation. In this dissertation, we experimentally investigate the internuclear-separation-dependent ionization of different molecular orbitals in neutral I₂. With a pump-probe scheme, a vibrational wavepacket is launched in the B state of I₂ by promoting an electron from the highest occupied molecular orbital (HOMO) to the lowest unoccupied molecular orbital (LUMO), and …