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Search for Supersymmetry in the Dilepton Final State with Taus at CDF Run II

Description: This thesis presents the results a search for chargino and neutralino supersymmetric particles yielding same signed dilepton final states including one hadronically decaying tau lepton using 6.0 fb{sup -1} of data collected by the the CDF II detector. This signature is important in SUSY models where, at high tan {beta}, the branching ratio of charginos and neutralinos to tau leptons becomes dominant. We study event acceptance, lepton identification cuts, and efficiencies. We set limits on the p… more
Date: September 1, 2011
Creator: Forrest, Robert David
Partner: UNT Libraries Government Documents Department
open access

Particle Deposition in Ventilation Ducts

Description: Exposure to airborne particles is detrimental to human health and indoor exposures dominate total exposures for most people. The accidental or intentional release of aerosolized chemical and biological agents within or near a building can lead to exposures of building occupants to hazardous agents and costly building remediation. Particle deposition in heating, ventilation and air-conditioning (HVAC) systems may significantly influence exposures to particles indoors, diminish HVAC performance a… more
Date: September 1, 2002
Creator: Sippola, Mark R.
Partner: UNT Libraries Government Documents Department
open access

Reflectance, Optical Properties, and Stability of Molybdenum/Strontium and Molybdenum/Yttrium Multilayer Mirrors

Description: The motivation of this work is to develop high reflectance normal-incidence multilayer mirrors in the 8-12 nm wavelength region for applications in astronomy and extreme ultraviolet lithography. To achieve this goal, Mo/Sr and Mo/Y multilayers were studied. These multilayers were deposited with a UHV magnetron sputtering system and their reflectances were measured with synchrotron radiation. High normal-incidence reflectances of 23% at 8.8 nm, 40.8% at 9.4 nm, and 48.3% at 10.5 nm were achieved… more
Date: September 1, 2002
Creator: Kjornrattanawanich, B
Partner: UNT Libraries Government Documents Department
open access

Search for supersymmetric partner of bottom quark at d0 at Tevatron. Studies on missing transverse energy

Description: Supersymmetry, extension of the Standard Model of Particle Physics (SM), is searched for by trying to observe the supersymmetric partner of bottom quark ({tilde b}). This search is performed using events with a final state comprising two acoplanar b-quark jets and missing transverse energy (MET) and coming from a sample of 992 pb{sup -1} of data collected by the D0 detector at the Tevatron, the Fermilab p{bar p} collider. The absence of an excess of events in comparison to MS expectations leads… more
Date: September 1, 2007
Creator: Calvet, Samuel Pierre
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Neutron electric form factor at Q2=0.8 2(GeV\\c)

Description: Nucleon form factors allow a sensitive test for models of the nucleon. Recent experiments utilising polarisation observables have resulted, for the first time, in a model-independent determination of the neutron electric form factor GnE. This method employed an 80% longitudinally polarised, high intensity (10 uA) electon beam (883 MeV) that was quasi-elastically scattered off a liquid deuterium target in the reaction D (e, en)p. A neutron polarimeter was designed and installed to measure the ra… more
Date: September 30, 2007
Creator: Glazier, Derek
Partner: UNT Libraries Government Documents Department
open access

Quantitative evaluation of material composition of composites using x-ray energy-dispersive NDE technique

Description: This technique worked well for determining the thickness and densities for composite components having the higher linear attenuation coefficient; it accurately determined thickness of epoxy-resin and Al metal, and the denisty of bone, to {le} 4% in the graphite-epoxy, bone-plexiglas, and Al-Al corrosion composites. Accuracy is dictated by the magnitude and uncertainty of the linear attenuation coefficient. Use of Ge detector and multichannel analyzer are limited by inspection time (1 day for po… more
Date: September 1, 1993
Creator: Ting, J.
Partner: UNT Libraries Government Documents Department
open access

Cracking behavior of cored structures

Description: The effects of compositional gradients, are considered based on a thermodynamic analysis, referred to as the Cahn-Hillard analysis, which describes the degree to which a local surface energy is modified by the presence of a composition gradient. The analysis predicts that both ductile and brittle fracture mechanisms are enhanced by the presence of a composition gradient. Data on stress corrosion cracking and fatigue crack growth in selected FCC alloys are used to illustrate the significance of … more
Date: September 1991
Creator: Wahid, A.; Olson, D.L.; Matlock, D.K. (Colorado School of Mines, Golden, CO (United States). Center for Welding and Joining Research) & Kelly, T.J. (General Electric Aircraft Engines, Evendale, OH (United States))
Partner: UNT Libraries Government Documents Department
open access

Cubic to tetragonal crystal lattice reconstruction during ordering or decomposition

Description: This thesis studied thermodynamic stability and morphology of product phases in diffusional phase transformations involving cubic-to-tetragonal crystal lattice reconstructions. Two different kinds of diffusional transformations were examined: L1{sub 0} ordering (fcc to fct lattice change) and decomposition of off-stoichiometric B2 ordering alloys accompanying bcc to fcc Bain transformation. In the first case, Fe-45 at.% Pd alloys were studied by TEM; in the second, the Bain strain relaxation du… more
Date: September 1, 1992
Creator: Cheong, Byung-kl
Partner: UNT Libraries Government Documents Department
open access

A Sterile-Neutrino Search with the MINOS Experiment

Description: The MINOS experiment is a long-baseline neutrino oscillation experiment in the the NuMI beamline at Fermilab, USA. Using a near detector at 1 km distance from the neutrino production target, and a far detector at 735 km from the target, it is designed primarily to measure the disappearance of muon neutrinos. This thesis presents an analysis using MINOS data of the possibility of oscil- lation of the neutrinos in the NuMI beam to a hypothetical sterile flavour, which would have no Standard Model… more
Date: September 1, 2010
Creator: Rodrigues, Philip
Partner: UNT Libraries Government Documents Department
open access

A Scaled Final Focus Experiment for Heavy Ion Fusion

Description: A one-tenth dimensionally scaled version of a final focus sub-system design for a heavy ion fusion driver is built and tested. By properly scaling the physics parameters that relate particle energy and mass, beam current, beam emittance, and focusing field, the transverse dynamics of a driver scale final focus are replicated in a small laboratory beam. The experiment uses a 95 {micro}A beam of 160 keV Cs{sup +} ions to study the dynamics as the beam is brought to a ballistic focus in a lattice … more
Date: September 19, 2000
Creator: MacLaren, Stephan, Alexander
Partner: UNT Libraries Government Documents Department
open access

Radiation environment simulations at the Tevatron, studies of the beam profile and measurement of the Bc meson mass

Description: The description of a computer simulation of the CDF detector at Fermilab and the adjacent accelerator parts is detailed, with MARS calculations of the radiation background in various elements of the model due to the collision of beams and machine-related losses. Three components of beam halo formation are simulated for the determination of the principal source of radiation background in CDF due to beam losses. The effect of a collimator as a protection for the detector is studied. The simulatio… more
Date: September 1, 2005
Creator: Nicolas, Ludovic Y. & U., /Glasgow
Partner: UNT Libraries Government Documents Department
open access

The discovery of high-redshift supernovae and their cosmological implications

Description: In this thesis the author discusses the methodology for doing photometry: from procedure of extracting supernova counts from images that contain combined supernova plus galaxy flux, to standard star calibration, to additional instrumental corrections that arise due to the multiple telescopes used for observations. He discusses the different sources of photometric error and their correlations, and the construction of the covariance matrix for all the points in the light curve. He then describes … more
Date: September 1, 1997
Creator: Kim, A.G.
Partner: UNT Libraries Government Documents Department
open access

A Search for Neutral Supersymmetric Higgs Bosons at D0

Description: A search for Higgs bosons in multijet data from the D0 detector is reported in this thesis. The Higgs boson is the only remaining undiscovered particle in the Standard Model of particle physics, and plays an integral role in this model. It is known that this model is not a complete description of fundamental physics (it does not describe gravity, for example), and so searches for physics beyond the Standard Model are an important part of particle physics. One extension of the Standard Model, th… more
Date: September 1, 2010
Creator: Osman, Nicolas Ahmed
Partner: UNT Libraries Government Documents Department
open access

An optimised oscillation analysis of MINOS beam data

Description: This thesis presents results of the MINOS long baseline neutrino oscillation experiment. Charged Current interactions of {nu}{sub {mu}} from the NuMI beamline have been recorded in both the Near and Far Detectors between May 2005 and February 2006, corresponding to 1.27 x 10{sup 20} protons being delivered to the NuMI target. Several techniques for improving the sensitivity of an oscillation measurement are discussed and their impact assessed. 378 events are observed in the Far Detector during … more
Date: September 1, 2007
Creator: Culling, Andrew John & U., /Cambridge
Partner: UNT Libraries Government Documents Department
open access

Quantifying Uranium Isotope Ratios Using Resonance Ionization Mass Spectrometry: The Influence of Laser Parameters on Relative Ionization Probability

Description: Resonance Ionization Mass Spectrometry (RIMS) has been developed as a method to measure relative uranium isotope abundances. In this approach, RIMS is used as an element-selective ionization process to provide a distinction between uranium atoms and potential isobars without the aid of chemical purification and separation. We explore the laser parameters critical to the ionization process and their effects on the measured isotope ratio. Specifically, the use of broad bandwidth lasers with autom… more
Date: September 6, 2011
Creator: Isselhardt, B H
Partner: UNT Libraries Government Documents Department
open access

Laser trapping of {sup 21}Na atoms

Description: This thesis describes an experiment in which about four thousand radioactive {sup 21}Na (t{sub l/2} = 22 sec) atoms were trapped in a magneto-optical trap with laser beams. Trapped {sup 21}Na atoms can be used as a beta source in a precision measurement of the beta-asymmetry parameter of the decay of {sup 21}Na {yields} {sup 21}Ne + {Beta}{sup +} + v{sub e}, which is a promising way to search for an anomalous right-handed current coupling in charged weak interactions. Although the number o trap… more
Date: September 1, 1994
Creator: Lu, Zheng-Tian
Partner: UNT Libraries Government Documents Department
open access

CCM Continuity Constraint Method: A finite-element computational fluid dynamics algorithm for incompressible Navier-Stokes fluid flows

Description: As the field of computational fluid dynamics (CFD) continues to mature, algorithms are required to exploit the most recent advances in approximation theory, numerical mathematics, computing architectures, and hardware. Meeting this requirement is particularly challenging in incompressible fluid mechanics, where primitive-variable CFD formulations that are robust, while also accurate and efficient in three dimensions, remain an elusive goal. This dissertation asserts that one key to accomplishin… more
Date: September 1, 1993
Creator: Williams, P. T.
Partner: UNT Libraries Government Documents Department
open access

The Cryogenic Dark Matter Search (CDMS-II) Experiment: First Results from the Soudan Mine

Description: There is an abundance of evidence that the majority of the mass of the universe is in the form of non-baryonic non-luminous matter that was non-relativistic at the time when matter began to dominate the energy density. Weakly Interacting Massive Particles, or WIMPs, are attractive cold dark matter candidates because they would have a relic abundance today of {approx}0.1 which is consistent with precision cosmological measurements. WIMPs are also well motivated theoretically. Many minimal supers… more
Date: September 1, 2004
Creator: Chang, Clarence Leeder
Partner: UNT Libraries Government Documents Department
open access

X-Ray Ablation Measurements and Modeling for ICF Applications

Description: X-ray ablation of material from the first wall and other components of an ICF (Inertial Confinement Fusion) chamber is a major threat to the laser final optics. Material condensing on these optics after a shot may cause damage with subsequent laser shots. To ensure the successful operation of the ICF facility, removal rates must be predicted accurately. The goal for this dissertation is to develop an experimentally validated x-ray response model, with particular application to the National Igni… more
Date: September 1, 1996
Creator: Anderson, A. T.
Partner: UNT Libraries Government Documents Department
open access

Surface structures from low energy electron diffraction: Atoms, small molecules and an ordered ice film on metal surfaces

Description: We investigated the surface bonding of various adsorbates (0, S, C{sub 2}H{sub 3} and NO) along with the resulting relaxation of the Pt(111) surface using low energy electron diffiraction (LEED). LEED experiments have been performed on these ordered overlayers along with theoretical structural analysis using automated tensor LEED (ATLEED). The resulting surface structures of these ordered overlayers exhibit similar adsorbate-induced relaxations. In all cases the adsorbate occupies the fcc hollo… more
Date: September 1, 1995
Creator: Materer, N.F.
Partner: UNT Libraries Government Documents Department
open access

The Development and Application of Reactive Transport Modeling Techniques to Study Radionuclide Migration at Yucca Mountain, NV

Description: Yucca Mountain, Nevada has been chosen as a possible site for the first high level radioactive waste repository in the United States. As part of the site investigation studies, we need to make scientifically rigorous estimations of radionuclide migration in the event of a repository breach. Performance assessment models used to make these estimations are computationally intensive. We have developed two reactive transport modeling techniques to simulate radionuclide transport at Yucca Mountain: … more
Date: September 1, 1999
Creator: Viswanathan, Hari Selvi
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Z-Boson Branching Fraction Into Hadrons Containing Bottom Quarks

Description: We use the Mark II detector to study Z decays into bottom quark-anti-quark pairs, leading to the production of bottom hadrons. The Z bosons are formed in e{sup +}e{sup {minus}} annihilation at the SLC at center-of-mass energies between 89 and 93 GeV. We identify events containing semileptonic decays of bottom hadrons by detecting isolated leptons, i.e leptons with high transverse momenta relative to the nearest hadronic jet. Using isolated electrons and muons, we measure the B-hadron semilepton… more
Date: September 1990
Creator: Kral, J. Frederic
Partner: UNT Libraries Government Documents Department
open access

Patterning nanocrystals using DNA

Description: One of the goals of nanotechnology is to enable programmed self-assembly of patterns made of various materials with nanometer-sized control. This dissertation describes the results of experiments templating arrangements of gold and semiconductor nanocrystals using 2'-deoxyribonucleic acid (DNA). Previously, simple DNA-templated linear arrangements of two and three nanocrystals structures have been made.[1] Here, we have sought to assemble larger and more complex nanostructures. Gold-DNA conjuga… more
Date: September 1, 2003
Creator: Williams, Shara Carol
Partner: UNT Libraries Government Documents Department
open access

Multi-atom resonant photoemission and the development of next-generation software and high-speed detectors for electron spectroscopy

Description: This dissertation has involved the exploration of a new effect in photoelectron emission, multi-atom resonant photoemission (MARPE), as well as the development of new software, data analysis techniques, and detectors of general use in such research. We present experimental and theoretical results related to MARPE, in which the photoelectron intensity from a core level on one atom is influenced by a core-level absorption resonance on another. We point out that some of our and others prior experi… more
Date: September 1, 2000
Creator: Kay, Alexander William
Partner: UNT Libraries Government Documents Department
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