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A Study of Factorization and a Measurement of CP Violation

Description: We report on a study of the decay {bar B}{sup 0} {yields} D*{sup +} {omega}{pi}{sup -} with the BABAR detector at the PEP-II B-factory at the Stanford Linear Accelerator Center. Based on a sample of 232 million B{sup 0}{bar B}{sup 0} decays collected between 1999 and 2004, we measure the branching fraction {Beta}({bar B}{sup 0} {yields} D*{sup +} {omega}{pi}{sup -}) = (2.88 {+-} 0.21(stat.) {+-} 0.31(syst.)) x 10{sup -3}. We study the invariant mass spectrum of the {omega}{pi}{sup -} system in … more
Date: January 16, 2008
Creator: Dahmes, Bryan
Partner: UNT Libraries Government Documents Department
open access

A Simultaneous Measurement of the Branching Fractions of Ten B to Double Charm Decays

Description: This dissertation presents a simultaneous measurement of the branching fractions of ten B {yields} D{sup (*)}{bar D}{sup (*)} decays. The measurements are derived from a sample of 2.32 x 10{sup 8} B{bar B} pairs collected by the BABAR detector at the PEP-II B Factory located at Stanford Linear Accelerator Center. The branching fractions (x 10{sup -4}) are: -0.10 {+-} 0.44 {+-} 0.15 (<0.59) for B{sup 0} {yields} D{sup 0}{bar D}{sup 0}; 1.01 {+-} 1.07 {+-} 0.35 (<2.92) for B{sup 0} {yields}… more
Date: January 16, 2008
Creator: Lae, Chung Khim
Partner: UNT Libraries Government Documents Department
open access

Search for Rare Quark-Annihilation Decays, Charged B Mesons Decaying to Charged D(S) Mesons And Phi Mesons

Description: The authors report on a search for the decay B{sup {+-}} {yields} D{sub s}{sup (*){+-}} {phi} using 212.2 fb{sup -1} of data collected with the BABAR detector at the PEP-II B Factory at the Stanford Linear Accelerator Center between 1999 and 2004. This sample of 234 x 10{sup 6} e{sup +}e{sup -} {yields} {Upsilon}(4S) {yields} B{bar B} events yields no significant signal. They report the Bayesian upper limits {Beta}(B{sup {+-}} {yields} D{sub s}{sup {+-}} {phi}) x {Beta}(D{sub s}{sup {+-}} {yiel… more
Date: January 16, 2008
Creator: Cunha, J.Adam M.
Partner: UNT Libraries Government Documents Department
open access

Single-Mode VISAR

Description: High energy-density physics (HEDP) experiments examine the properties of materials under extreme conditions. These experiments rely on the measurement of one or two velocities. These velocities are used to obtain Hugoniot relationships and thermodynamic equations of state. This methodology is referred to as 'velocimetry' and an instrument used to measure the shock wave is called a 'velocimeter' or a '(velocity) diagnostic'. The two most-widely used existing velocity diagnostics are; photonic Do… more
Date: November 16, 2007
Creator: Krauter, K
Partner: UNT Libraries Government Documents Department
open access

A Search for B+ to K+ Nu Anti-Nu

Description: A search for the rare, flavour-changing neutral current decay B{sup +} {yields} K{sup +} {nu}{bar {nu}} is presented using 81.9 fb{sup -1} of data collected at the {Upsilon}(4S) resonance by the BABAR experiment. Signal candidate events are selected through the identification of a high momentum charged kaon and significant missing energy, where the companion B{sup -} in the event has decayed semileptonically via B{sup -} {yields} D{sup 0}{ell}{sup -}{bar {nu}} X and X is kinematically constrain… more
Date: January 16, 2008
Creator: Jackson, Paul D.
Partner: UNT Libraries Government Documents Department
open access

Measurement of Cabibbo-Suppressed Tau Lepton Decays and the Determination of |Vus|

Description: This work presents simultaneous branching fraction measurements of the decay modes {tau}{sup -} {yields} K{sup -} n{pi}{sup 0}{nu}{sub {tau}} with n = 0,1,2,3 and {tau}{sup -} {yields} {pi}{sup -} n{pi}{sup 0}{nu}{sub {tau}} with n = 3,4. The analysis is based on a data sample of 427 x 10{sup 6} {tau}{sup +}{tau}{sup -} pairs recorded with the BABAR detector, which corresponds to an integrated luminosity of 464.4 fb{sup -1}. The measured values are {Beta}({tau}{sup -} {yields} K{sup -}{nu}{sub … more
Date: December 16, 2008
Creator: Schenk, Stefan
Partner: UNT Libraries Government Documents Department
open access

Experimental and Numerical Investigation of the Role of Initial Condition of the Dynamics of Rayleigh-Taylor Mixing

Description: Experiments and direct numerical simulations have been performed to examine the effects of initial conditions on the dynamics of a Rayleigh-Taylor mixing layer. Experiments were performed on a water channel facility to quantify the interfacial and velocity perturbations initially present at the two-fluid interface in a small Atwood number mixing layer. The measurements have been parameterized for implementation in numerical simulations of the experiment, and two- and three-dimensional direct nu… more
Date: August 16, 2004
Creator: Mueschke, N
Partner: UNT Libraries Government Documents Department
open access

Evaluating Radionuclide Air Emission Stack Sampling Systems

Description: The Pacific Northwest National Laboratory (PNNL) operates a number of research and development (R&D) facilities for the U.S. Department of Energy at the Hanford Site, Washington. These facilities are subject to Clean Air Act regulations that require sampling of radionuclide air emissions from some of these facilities. A revision to an American National Standards Institute (ANSI) standard on sampling radioactive air emissions has recently been incorporated into federal and state regulations and … more
Date: December 16, 2002
Creator: Ballinger, Marcel Y.
Partner: UNT Libraries Government Documents Department
open access

Investigation of organometallic reaction mechanisms with one and two dimensional vibrational spectroscopy

Description: One and two dimensional time-resolved vibrational spectroscopy has been used to investigate the elementary reactions of several prototypical organometallic complexes in room temperature solution. The electron transfer and ligand substitution reactions of photogenerated 17-electron organometallic radicals CpW(CO){sub 3} and CpFe(CO){sub 2} have been examined with one dimensional spectroscopy on the picosecond through microsecond time-scales, revealing the importance of caging effects and odd-ele… more
Date: December 16, 2008
Creator: Cahoon, James Francis
Partner: UNT Libraries Government Documents Department
open access

Measurement of the top quark pair production cross section in proton-antiproton collisions at a center of mass energy of 1.96 TeV, hadronic top decays with the D0 detector

Description: Of the six quarks in the standard model the top quark is by far the heaviest: 35 times more massive than its partner the bottom quark and more than 130 times heavier than the average of the other five quarks. Its correspondingly small decay width means it tends to decay before forming a bound state. Of all quarks, therefore, the top is the least affected by quark confinement, behaving almost as a free quark. Its large mass also makes the top quark a key player in the realm of the postulated Hig… more
Date: January 16, 2009
Creator: Hegeman, Jeroen Guido
Partner: UNT Libraries Government Documents Department
open access

Fabrication of Yttria stabilized zirconia thin films on poroussubstrates for fuel cell applications

Description: A process for the deposition of yttria stabilized zirconia (YSZ) films, on porous substrates, has been developed. These films have possible applications as electrolyte membranes in fuel cells. The films were deposited from colloidal suspensions through the vacuum infiltration technique. Films were deposited on both fully sintered and partially sintered substrates. A critical cracking thickness for the films was identified and strategies are presented to overcome this barrier. Green film density… more
Date: June 16, 2003
Creator: Leming, Andres
Partner: UNT Libraries Government Documents Department
open access

Toward Femtosecond X-ray Spectroscopy at the Advanced Light Source

Description: The realization of tunable, ultrashort pulse x-ray sources promises to open new venues of science and to shed new light on long-standing problems in condensed matter physics and chemistry. Fundamentally new information can now be accessed. Used in a pump-probe spectroscopy, ultrashort x-ray pulses provide a means to monitor atomic rearrangement and changes in electronic structure in condensed-matter and chemical systems on the physically-limiting time-scales of atomic motion. This opens the way… more
Date: April 16, 2004
Creator: Chong, Henry Herng Wei
Partner: UNT Libraries Government Documents Department
open access

I. Excluded Volume Effects in Ising Cluster Distributions and Nuclear Multifragmentation II. Multiple-Chance Effects in Alpha-Particle Evaporation

Description: In Part 1, geometric clusters of the Ising model are studied as possible model clusters for nuclear multifragmentation. These clusters may not be considered as non-interacting (ideal gas) due to excluded volume effect which predominantly is the artifact of the cluster's finite size. Interaction significantly complicates the use of clusters in the analysis of thermodynamic systems. Stillinger's theory is used as a basis for the analysis, which within the RFL (Reiss, Frisch, Lebowitz) fluid-of-sp… more
Date: May 16, 2005
Creator: Breus, Dimitry E.
Partner: UNT Libraries Government Documents Department
open access

Rates and progenitors of type Ia supernovae

Description: The remarkable uniformity of Type Ia supernovae has allowed astronomers to use them as distance indicators to measure the properties and expansion history of the Universe. However, Type Ia supernovae exhibit intrinsic variation in both their spectra and observed brightness. The brightness variations have been approximately corrected by various methods, but there remain intrinsic variations that limit the statistical power of current and future observations of distant supernovae for cosmological… more
Date: August 16, 2004
Creator: Wood-Vasey, William Michael
Partner: UNT Libraries Government Documents Department
open access

Photon and Neutral Pi 0 production in (197)Au + (197)Au collisions at sqrt S(NN) = 130 GeV

Description: Inclusive transverse momentum spectra of photons and {pi}{sup 0}s at mid-rapidity are studied as a function of collision centrality for {sup 197}Au+ {sup 197}Au collisions at {radical}s{sub NN} = 130 GeV. Photon pair conversions have been reconstructed from charged tracks measured by the main Time Project Chamber of the STAR experiment at the RHIC heavy ion facility. The transverse momentum resolution of photons with this method is estimated to be {Delta}p{sub t}/p{sub t} = 2% at 0.125 GeV/c an… more
Date: September 16, 2002
Creator: Johnson, Ian J.
Partner: UNT Libraries Government Documents Department
open access

In Situ Adsorption Studies at the Solid/Liquid Interface:Characterization of Biological Surfaces and Interfaces Using SumFrequency Generation Vibrational Spectroscopy, Atomic Force Microscopy,and Quartz Crystal Microbalance

Description: Sum frequency generation (SFG) vibrational spectroscopy, atomic force microscopy (AFM), and quartz crystal microbalance (QCM) have been used to study the molecular surface structure, surface topography and mechanical properties, and quantitative adsorbed amount of biological molecules at the solid-liquid interface. The molecular-level behavior of designed peptides adsorbed on hydrophobic polystyrene and hydrophilic silica substrates has been examined as a model of protein adsorption on polymeri… more
Date: May 16, 2006
Creator: Phillips, Diana Christine
Partner: UNT Libraries Government Documents Department
open access

Ultrasonic Digital Communication System for a Steel Wall Multipath Channel: Methods and Results

Description: As of the development of this thesis, no commercially available products have been identified for the digital communication of instrumented data across a thick ({approx} 6 n.) steel wall using ultrasound. The specific goal of the current research is to investigate the application of methods for digital communication of instrumented data (i.e., temperature, voltage, etc.) across the wall of a steel pressure vessel. The acoustic transmission of data using ultrasonic transducers prevents the need … more
Date: February 16, 2006
Creator: Murphy, TL
Partner: UNT Libraries Government Documents Department
open access

A measurement of t{anti t} production cross section in p{anti p} collisions at {radical}s = 1.8 TeV using neural networks

Description: The authors present the results of a new measurement of the t{anti t} production cross section using e{mu} channel in p{anti p} collisions at {radical}s = 1.8 TeV. This study corresponds to an integrated luminosity of 108.3 {+-} 5.7 pb{sup {minus}1} acquired by the D0 detector during the Fermilab Tevatron Collider Run 1 (1992--1996). By using neural network techniques instead of the conventional analysis methods, the authors show that the signal acceptance can be increased by 10% (for m{sub t} … more
Date: June 16, 2000
Creator: Singh, Harpreet
Partner: UNT Libraries Government Documents Department
open access

X-ray and vibrational spectroscopy of manganese complexes relevant to the oxygen-evolving complex of photosynthesis

Description: Manganese model complexes, relevant to the oxygen-evolving complex (OEC) in photosynthesis, were studied with Mn K-edge X-ray absorption near-edge spectroscopy (XANES), Mn Kb X-ray emission spectroscopy (XES), and vibrational spectroscopy. A more detailed understanding was obtained of the influence of nuclearity, overall structure, oxidation state, and ligand environment of the Mn atoms on the spectra from these methods. This refined understanding is necessary for improving the interpretation o… more
Date: May 16, 2001
Creator: Visser, Hendrik
Partner: UNT Libraries Government Documents Department
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