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Search for charged Higgs bosons in decays of top quarks in proton - antiproton collisions at s**(1/2) = 1.96 TeV

Description: In this dissertation we report on the first direct search for charged Higgs bosons in decays of top quarks in p{bar p} collisions at {radical}s = 1.96 TeV. The search uses a data sample with an integrated luminosity of 2.2 fb{sup -1} collected by the CDF II detector at Fermilab and looks for a resonance in the invariant mass distribution of two jets in the lepton+jets sample of t{bar t} candidates. We observe no evidence of charged Higgs bosons in top quark decays; hence 95% C.L. upper limits o… more
Date: August 1, 2009
Creator: Yu, Geum Bong
Partner: UNT Libraries Government Documents Department
open access

A Voltage Controlled Oscillator for a Phase-Locked Loop Frequency Synthesizer in a Silicon-on-Sapphire Process

Description: Engineers from a government-owned engineering and manufacturing facility were contracted by government-owned research laboratory to design and build an S-band telemetry transmitter using Radio Frequency Integrated Circuit (RFIC) technology packaged in a Low-Temperature Co-fired Ceramic (LTCC) Multi-Chip Module. The integrated circuit technology chosen for the Phase-Locked Loop Frequency Synthesizer portion of the telemetry transmitter was a 0.25 um CMOS process that utilizes a sapphire substrat… more
Date: May 21, 2009
Creator: Garrison, Sean
Partner: UNT Libraries Government Documents Department
open access

Building Structural Complexity in Semiconductor Nanocrystals through Chemical Transformations

Description: Methods are presented for synthesizing nanocrystal heterostructures comprised of two semiconductor materials epitaxially attached within individual nanostructures. The chemical transformation of cation exchange, where the cations within the lattice of an ionic nanocrystal are replaced with a different metal ion species, is used to alter the chemical composition at specific regions ofa nanocrystal. Partial cation exchange was performed in cadmium sulfide (CdS) nanorods of well-defined size and s… more
Date: May 20, 2009
Creator: Sadtler, Bryce F.
Partner: UNT Libraries Government Documents Department
open access

Search for the Standard Model Higgs Boson in associated production with w boson at the Tevatron

Description: A search for the Standard Model Higgs boson in proton-antiproton collisions with center-of-mass energy 1.96 TeV at the Tevatron is presented in this dissertation. The process of interest is the associated production of W boson and Higgs boson, with the W boson decaying leptonically and the Higgs boson decaying into a pair of bottom quarks. The dataset in the analysis is accumulated by the D0 detector from April 2002 to April 2008 and corresponding to an integrated luminosity of 2.7 fb{sup -1}. … more
Date: November 1, 2009
Creator: Chun, Xu
Partner: UNT Libraries Government Documents Department
open access

Search for the Standard Model Higgs boson in the decay mode H-> WW-> lnulnu

Description: The question of the nature and principles of the universe and our place in it is the driving force of science since Mesopotamian astronomers glanced for the first time at the starry sky and Greek atomism has been formulated. During the last hundred years modern science was able to extend its knowledge tremendously, answering many questions, opening entirely new fields but as well raising many new questions. Particularly Astronomy, Astroparticle Physics and Particle Physics lead the race to answ… more
Date: September 1, 2009
Creator: Penning, B.
Partner: UNT Libraries Government Documents Department
open access

From ZZ to ZH : How Low Can These Cross Sections Go or Everybody, Let's Cross Section Limbo!

Description: We report on two searches performed at the D0 detector at the Fermi National Laboratory. The first is a search for Z di-boson production with a theoretical cross section of 1.4 pb. The search was performed on 2.6 fb{sup -1} of data and contributed to the first observation of ZZ production at a hadron collider. The second is a search for a low mass Standard Model Higgs in 4.2 fb{sup -1} of data. The Higgs boson is produced in association with a Z boson where the Higgs decays hadronically and the… more
Date: August 1, 2009
Creator: Strauss, Emanuel Alexandre
Partner: UNT Libraries Government Documents Department
open access

Measurements of the Differential Cross Sections for the Inclusive Production of a Photon and Heavy Flavor Jet

Description: This thesis presents the first measurement of the differential production cross section of a heavy flavor (bottom or charm) jet and direct photon at the Fermilab Tevatron. These measurements were performed using data recorded with the D0 detector from proton-antiproton collisions at a center of mass energy of {radical}s = 1.96 TeV. These results probe a kinematic range for the photon transverse momentum of 30 < p{sub T}{sup {gamma}} < 150 GeV and rapidity of |y{sup {gamma}}| < 1.0 and … more
Date: April 1, 2009
Creator: Duggan, Daniel
Partner: UNT Libraries Government Documents Department
open access

Neutrino-nucleus neutral current elastic interactions measurement in MiniBooNE

Description: The MiniBooNE experiment at the Fermi National Accelerator Laboratory (Fermilab) was designed to search for {nu}{sub {mu}} {yields} {nu}{sub e} neutrino oscillations at {Delta}m{sup 2} {approx} 1 eV{sup 2} using an intense neutrino flux with an average energy E{sub {nu}} {approx} 700 MeV. From 2002 to 2009 MiniBooNE has accumulated more than 1.0 x 10{sup 21} protons on target (POT) in both neutrino and antineutrino modes. MiniBooNE provides a perfect platform for detailed measurements of exclus… more
Date: December 1, 2009
Creator: Perevalov, Denis & U., /Alabama
Partner: UNT Libraries Government Documents Department
open access

Study of B-Meson Decays to Final States with a Single Charm Baryon

Description: A study of B-meson decays to final states with a single charm baryon is presented based on data recorded by the BABAR detector at the Stanford Linear Accelerator Center. Although the B meson is the lightest bottom-flavored meson, it is heavy enough to decay to a baryon made of three quarks and an antibaryon made of three antiquarks. By studying the baryonic weak decays of the B meson, we can investigate baryon production mechanisms in heavy meson decays. In particular, we measure the rates of t… more
Date: June 2, 2009
Creator: Majewski, Stephanie A.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the branching fraction Bs->Ds(*)Ds(*) using the D0 detector at Fermilab

Description: This thesis describes a measurement of the branching fraction Br(B{sup 0}{sub s} {yields} D{sup (*)}{sub s} D{sup (*)}{sub s}) made using a data sample collected from proton-antiproton collisions at a centre-of-mass energy of 1.96 TeV, corresponding to approximately 1.3 fb{sup -1} of integrated luminosity collected in 2002--2006 by the D0 detector at the Fermilab Tevatron Collider. One D{sup (*)}{sub s} meson was partially reconstructed in the decay D{sub s} {yields} {phi}{mu}{nu}, and the othe… more
Date: February 1, 2009
Creator: Walder, James William
Partner: UNT Libraries Government Documents Department
open access

Optical galaxy cluster detection across a wide redshift range

Description: The past decade is one of the most exciting period in the history of physics and astronomy. The discovery of cosmic acceleration dramatically changed our understanding about the evolution and constituents of the Universe. To accommodate the new acceleration phase into our well established Big Bang cosmological scenario under the frame work of General Relativity, there must exist a very special substance that has negative pressure and make up about 73% of the total energy density in our Universe… more
Date: April 1, 2009
Creator: Hao, Jiangang
Partner: UNT Libraries Government Documents Department
open access

Measurement of the Oscillation Frequency of B_s Mesons in the Hadronic Decay Mode B_s-> pi D_s(phi pi)X$ with the D0 Detector at the Fermilab Tevatron Collider

Description: The standard model (SM) of particle physics is a theory, describing three out of four fundamental forces. In this model the Cabibbo-Kobayashi-Maskawa (CKM) matrix describes the transformation between the mass and weak eigenstates of quarks. The matrix properties can be visualized as triangles in the complex plane. A precise measurement of all triangle parameters can be used to verify the validity of the SM. The least precisely measured parameter of the triangle is related to the CKM element |V{… more
Date: March 1, 2009
Creator: Weber, Gernot August & /Mainz U., Inst. Phys.
Partner: UNT Libraries Government Documents Department
open access

Neutrino and antineutrino inclusive charged-current cross section measurement with the MINOS near detector

Description: This thesis presents the measurement of energy dependence of the neutrino-nucleon inclusive charged current cross section on an isoscalar target in the range 3-50 GeV for neutrinos and 5-50 GeV energy range for antineutrinos. The data set was collected with the MINOS Near Detector using the wide band NuMI beam at Fermilab. The size of the charged current sample is 1.94 x 10{sup 6} neutrino events and 1.60 x 10{sup 5} antineutrino events. The flux has been extracted using a low hadronic energy s… more
Date: March 1, 2009
Creator: Bhattacharya, Debdatta & U., /Pittsburgh
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

Search for Charged Massive Long-Lived Particles Using the D0 Detector

Description: A search for charged massive stable particles has been performed with the D0 detector using 1.1 fb{sup -1} of data. The speed of the particle has been calculated based on the time-of-flight and position information in the muon system. The present research is limited to direct pair-production of the charged massive long-lived particles. We do not consider CMSPs that result from the cascade decays of heavier particles. In this analysis, the exact values of the model parameters of the entire super… more
Date: May 1, 2009
Creator: Xie, Yunhe & U., /Brown
Partner: UNT Libraries Government Documents Department
open access

Considering value of information when using CFD in design

Description: This thesis presents an approach to find lower resolution CFD models that can accurately lead a designer to a correct decision at a lower computational cost. High-fidelity CFD models often contain too much information and come at a higher computational cost, limiting the designs a designer can test and how much optimization can be performed on the design. Lower model resolution is commonly used to reduce computational time. However there are no clear guidelines on how much model accuracy is req… more
Date: December 19, 2009
Creator: Misra, John Satprim
Partner: UNT Libraries Government Documents Department
open access

Neutral Supersymmetric Higgs Boson Searches

Description: In some Supersymmetric extensions of the Standard Model, including the Minimal Supersymmetric Standard Model (MSSM), the coupling of Higgs bosons to b-quarks is enhanced. This enhancement makes the associated production of the Higgs with b-quarks an interesting search channel for the Higgs and Supersymmetry at D0. The identification of b-quarks, both online and offline, is essential to this search effort. This thesis describes the author's involvement in the development of both types of b-taggi… more
Date: September 1, 2009
Creator: Robinson, Stephen Luke
Partner: UNT Libraries Government Documents Department
open access

Direct analysis of samples by mass spectrometry: From elements to bio-molecules using laser ablation inductively couple plasma mass spectrometry and laser desorption/ionization mass spectrometry

Description: Mass spectrometric methods that are able to analyze solid samples or biological materials with little or no sample preparation are invaluable to science as well as society. Fundamental research that has discovered experimental and instrumental parameters that inhibit fractionation effects that occur during the quantification of elemental species in solid samples by laser ablation inductively coupled plasma mass spectrometry is described. Research that determines the effectiveness of novel laser… more
Date: August 19, 2009
Creator: Perdian, David C.
Partner: UNT Libraries Government Documents Department
open access

Measurement of the W boson mass and width using a novel recoil model

Description: This dissertation presents a direct measurement of the W boson mass (M{sub W}) and decay width ({Lambda}{sub W}) in 1 fb{sup -1} of W {yields} e{nu} collider data at D0 using a novel method to model the hadronic recoil. The mass is extracted from fits to the transverse mass M{sub T}, p{sub T}(e), and E{sub T} distributions. The width is extracted from fits to the tail of the M{sub T} distribution. The electron energy measurement is simulated using a parameterized model, and the recoil is modele… more
Date: January 1, 2009
Creator: Wetstein, Matthew J.
Partner: UNT Libraries Government Documents Department
open access

Correlations in bottom quark pair production at the Fermilab Tevatron

Description: I present an analysis of b{bar b} pair production correlations, using dimuon-triggered data collected with the Collider Detector at Fermilab (CDF) in p{bar p} collisions at {radical}s = 1.96 TeV during Run II of the TeVatron. The leading order (LO) and next-to-leading order (NLO) b quark production processes are discriminated by the angular and momentum correlations between the b{bar b} pair. Track-level jets containing a muon are classified by b quark content and used to estimate the momentum … more
Date: January 1, 2009
Creator: Galyardt, Jason Edward
Partner: UNT Libraries Government Documents Department
open access

Bioinspired synthesis of magnetic nanoparticles

Description: The synthesis of magnetic nanoparticles has long been an area of active research. Magnetic nanoparticles can be used in a wide variety of applications such as magnetic inks, magnetic memory devices, drug delivery, magnetic resonance imaging (MRI) contrast agents, and pathogen detection in foods. In applications such as MRI, particle uniformity is particularly crucial, as is the magnetic response of the particles. Uniform magnetic particles with good magnetic properties are therefore required. O… more
Date: May 26, 2009
Creator: David, Anand
Partner: UNT Libraries Government Documents Department
open access

Scientist-Teacher Partnerships as Professional Development: An Action Research Study

Description: SUBMITTED AS A DOCTORAL DISSERTATION IN COMPLETION OF REQUIREMENTS FOR THE DEGREE OF ED.D THROUGH WASHINGTON STATE UNIVERSITY. The overall purpose of this action research study was to explore the experiences of ten middle school science teachers involved in a three-year partnership program between scientists and teachers at a Department of Energy national laboratory, including the impact of the program on their professional development, and to improve the partnership program by developing a set… more
Date: April 17, 2009
Creator: Willcuts, Meredith H.
Partner: UNT Libraries Government Documents Department
open access

Search for the Standard Model Higgs Boson in the Missing Transverse Energy and b-jet signature in proton-antiproton collisions at a center-of-mass energy of 1.96 TeV

Description: We report on the results of a search for the standard model Higgs boson produced in association with a W or Z boson in p{bar p} collisions at {radical}s = 1.96 TeV recorded by the CDF II experiment at the Tevatron in a data sample corresponding to an integrated luminosity of 2.1 fb{sup -1}. We consider events having no identified charged leptons, a large imbalance in transverse momentum, and two or three jets where at least one jet contains a secondary vertex consistent with the decay of a b ha… more
Date: May 1, 2009
Creator: Apresyan, Artur
Partner: UNT Libraries Government Documents Department
open access

Development of extreme ultraviolet and soft x-ray multilayer optics for scientific studies with femtosecond/attosecond sources

Description: The development of multilayer optics for extreme ultraviolet (EUV) radiation has led to advancements in many areas of science and technology, including materials studies, EUV lithography, water window microscopy, plasma imaging, and orbiting solar physics imaging. Recent developments in femtosecond and attosecond EUV pulse generation from sources such as high harmonic generation lasers, combined with the elemental and chemical specificity provided by EUV radiation, are opening new opportunities… more
Date: May 21, 2009
Creator: Aquila, Andrew Lee
Partner: UNT Libraries Government Documents Department
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