Physics Commons^™

Fermi-Unsmearing In Single Charged Pion Electroproduction Cross-Section Measurements For The Neutron And Proton In Deuterium, Gary Hollis

Theses and Dissertations

Electron scattering cross-sections for two different reaction channels, e- + p→ e- + n + ϖ + and e- + n → e- + p ϖ - using an unpolarized deuterium target, were extracted from Jefferson Lab experiment E1E data with a beam energy of 2.039 GeV, providing a (W;Q2) coverage of 1.1 GeV < W < 1.9 GeV and0.4 GeV2< Q2 2. Although there has already been an analysis of this same data set for the second reaction channel listed above [1], more of the cross-section domain has been covered in this analysis due to applying a new technique called Fermi-unsmearing. Fermi-smearing is a distortion in a cross-section measurement which occurs whenever the target is erroneously assumed to be at rest but is in fact a bound nucleon as part of a larger nucleus (and thus is in Fermi-motion). Fermi-unsmearing is a Monte Carlo method presented in this work for generating a correction factor that removes the Fermi-smearing effect from an existing cross-section measurement that suffers from Fermi-smearing. Using Fermi-unsmearing can have the advantage of significantly larger statistical sample sizes given the same data set due to allowing less strict final data selection criteria, as occurs in a Fermi-unsmeared analysis of the e- + n→ e- + p + ϖ- channel in contrast to a fully-exclusive analysis of the same channel. The same Fermi-unsmearing method is applied to the first channel after having established the efficacy of the method using the second channel.

Methods For Cancellation Of Apparent Cerenkov Radiation Arising From Sme Models And Separability Of Schrödinger’S Equation Using Exotic Potentials In Parabolic Coordinates, Richard Henry Decosta

Theses and Dissertations

In an attempt to merge the two prominent areas of physics: The Standard Model and General Relativity, there have been many theories for the underlying physics that may lead to Lorentz- and CPT-symmetry violations. At the present moment, technology allows numerous types of Planck-sensitive tests of these symmetries in a range of physical systems.

We address a curiosity in isotropic CPT- and Lorentz-violating electrodynamics where there is a kinematic allowance for Cerenkov radiation of a charged particle in a vacuum moving with uniform motion. This however, should not be the case as it is known that constant motion in a …

Neutrino Induced Coherent-Pion: Precision Measurement In Nomad And Uses In Oscillation Experiments, Bing Guo

Theses and Dissertations

In the era of high precision oscillation measurements, lead by DUNE and Hyper-K, the Near Detector (ND) faces unprecedented challenges and opportunities. Among the various neutrino events in ND, Coherent meson production plays a special role. It is a non-negligible background to the oscillation signal. However the cross-section models for neutrino induced Coherent meson currently being used are old and imprecise. On the other hand, Coherent meson has a simple experimental signature with minimal nuclear effect making it unique among neutrino-nucleon interactions. Furthermore, the cross section for Coherent meson is the same in neutrino and antineutrino modes. It, thus, potentially …

Cosmic Metal Evolution During The First ∼1 Billion Years After The Big Bang Using Damped/Sub-Damped Lyman-Alpha Absorbers, Suraj Poudel

Theses and Dissertations

Metal abundance measurements throughout the cosmic ages track the history of galaxy formation and evolution. Measuring abundances during the first ∼1 billion years is especially important, as they are influenced by the nucleosynthetic signatures from the early stars. Evolution of metallicity of Damped/sub-Damped Lyman-alpha Absorbers (DLAs/sub-DLAs) detected in the spectra of quasars is a powerful tracer of the cosmic star formation history. A sudden drop in DLA metallicity at z>4.7 was reported in some recent studies. However, these studies were primarily based on refractory elements such as Fe and Si. We present ten new abundance measurements of the elements …

Probing The Interstellar Medium Of Galaxies Using Gravitationally Lensed Sight Lines And The Relevant Atomic Physics, Frances Cashman

Theses and Dissertations

Absorption spectroscopy of gravitationally lensed quasars (GLQs) enables study of spatial variations in the interstellar and/or circumgalactic medium (ISM, CGM) of foreground galaxies. In this work I present observations of 4 GLQs, each with two images separated by 0.8-3.000, that show strong absorbers at redshifts 0.4 abs< 1.3 in their spectra, including some at the lens redshift. The H I Lyman lines were measured in five absorbers using HST-STIS, and metal lines with either the MagE spectrograph or the Sloan Digital Sky Survey. These data, combined with the literature, show no strong correlation between absolute values of differences in NH I, NFe II, or [Fe/H] and sight line separations at absorber redshifts. The measured abundance gradients show a tentative anti-correlation with abundances at galaxy centers.

A study of the lens galaxy foreground to the doubly lensed quasar SBS 0909+532 reveals a large difference in H I and metal column densities between sight lines. Using archival HST-STIS and Keck HIRES spectra, log N _{H I} 18.18 cm−2 and log N _{H I} = 20.38±0.02 cm⁻²were measured, resulting …

What Can Scattered Light Tell You About Your Favorite Magnetic Material?: A Magneto Optical Investigation Of The Magnetic Properties Of Aligned Janus Fiber Agglomerates.Influence Of Dynamic Multiaxial Transverse Loading On Ultrahigh Molecular Weight Polyethylene Single Fiber Failure, Cory John Dolbashian

Theses and Dissertations

Here we seek to take a traditional Magneto Optic Kerr Effect (MOKE) experimental design, useful for local magnetization measurements, and apply it to measuring aligned multiferroic Janus nano fiber agglomerates. In order to achieve this we modify the traditional MOKE geometry by measuring our Kerr rotation from collimated scattered light, rather than the conventional specular reflection. Using various techniques to improve signal to noise ratio (SNR), we extend the application of this scattered MOKE geometry to build families of First Order Reversal Curves (FORC). Using an alternative analysis technique, FORC curves are processed and become a FORC diagram, which is …