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Quantum Dynamical Behaviour in Complex Systems - A Semiclassical Approach

Description: One of the biggest challenges in Chemical Dynamics is describing the behavior of complex systems accurately. Classical MD simulations have evolved to a point where calculations involving thousands of atoms are routinely carried out. Capturing coherence, tunneling and other such quantum effects for these systems, however, has proven considerably harder. Semiclassical methods such as the Initial Value Representation (SC-IVR) provide a practical way to include quantum effects while still utilizing… more
Date: May 22, 2008
Creator: Gliebe, Cheryn E & Ananth, Nandini
Partner: UNT Libraries Government Documents Department
open access

Radiative B Meson Decay as a Probe of Physics Beyond the Standard Model: Time-Dependent CP Violation in B0 --> KS pi0 gamma and the B --> phi K gamma Branching Fraction

Description: The author presents measurements of radiative B meson decays to the final states K{sub s}{sup 0}{pi}{sup 0}{gamma} and K{phi}{gamma} based on data collected at the {Upsilon}(4S) resonance with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at SLAC. In a data sample of 467 million B{bar B} pairs, the time-dependent CP asymmetry in B{sup 0} {yields} K{sub s}{sup 0}{pi}{sup 0}{gamma} decays is measured in two regions of K{sub s}{sup 0}-{pi}{sup 0} invariant mass. In the K* region, 0.8 … more
Date: January 22, 2009
Creator: Tuggle, Joseph Marion, IV
Partner: UNT Libraries Government Documents Department
open access

Measurements of Time-Dependent CP-Asymmetry Parameters in B Meson Decays to \eta^{\prime} K^0 and of Branching Fractions of SU(3) Related Modes with BaBar Experiment at SLAC

Description: In this thesis work we have measured the following upper limits at 90% of confidence level, for B meson decays (in units of 10{sup -6}), using a statistics of 465.0 x 10{sup 6} B{bar B} pairs: {Beta}(B{sup 0} {yields} {eta}K{sup 0}) < 1.6 {Beta}(B{sup 0} {yields} {eta}{eta}) < 1.4 {Beta}(B{sup 0} {yields} {eta}{prime}{eta}{prime}) < 2.1 {Beta}(B{sup 0} {yields} {eta}{phi}) < 0.52 {Beta}(B{sup 0} {yields} {eta}{omega}) < 1.6 {Beta}(B{sup 0} {yields} {eta}{prime}{phi}) < 1.2 {Be… more
Date: January 22, 2009
Creator: Biassoni, Pietro & U., /Milan
Partner: UNT Libraries Government Documents Department
open access

Detection of Actinides via Nuclear Isomer De-Excitation

Description: This dissertation discusses a data collection experiment within the Actinide Isomer Identification project (AID). The AID project is the investigation of an active interrogation technique that utilizes nuclear isomer production, with the goal of assisting in the interdiction of illicit nuclear materials. In an attempt to find and characterize isomers belonging to 235U and its fission fragments, a 232Th target was bombarded with a monoenergetic 6Li ion beam, operating at 45 MeV.
Date: July 22, 2009
Creator: Francy, Christopher J.
Partner: UNT Libraries Government Documents Department
open access

Novel joining of dissimilar ceramics in the Si{sub 3}N{sub 4}-Al{sub 2}O{sub 3} system using polytypoid functional gradients

Description: A unique approach to crack-free joining of heterogeneous ceramics is demonstrated by the use of sialon polytypoids as Functionally Graded Materials (FGM) as defined by the phase diagram in the system, Si3N4-Al2O3. Polytypoids in the Al2O3-Si3N4 system offer a path to compatibility for such heterogeneous ceramics. The first part of the dissertation describes successful hot press sintering of multilayered FGM's with 20 layers of thickness 500 mm each. Transmission Electron Microscopy was used to … more
Date: August 22, 2001
Creator: Lee, Caroline Sunyong
Partner: UNT Libraries Government Documents Department
open access

Superconducting High Energy Resolution Gamma-ray Spectrometers

Description: We have demonstrated that a bulk absorber coupled to a TES can serve as a good gamma-ray spectrometer. Our measured energy resolution of 70 eV at 60 keV is among the best measurements in this field. We have also shown excellent agreement between the noise predictions and measured noise. Despite this good result, we noted that our detector design has shortcomings with a low count rate and vulnerabilities with the linearity of energy response. We addressed these issues by implementation of an act… more
Date: February 22, 2002
Creator: Chow, Daniel Tun Lai
Partner: UNT Libraries Government Documents Department
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