Search for lepton flavor violating decay τ<sup>-</sup> →ℓ<sup>-</sup>ℓ<sup>+</sup>ℓ<sup>-</sup>ℓ = e, μ at BaBar (open access)

Search for lepton flavor violating decay τ<sup>-</sup> →ℓ<sup>-</sup>ℓ<sup>+</sup>ℓ<sup>-</sup>ℓ = e, μ at BaBar

The Standard Model (SM) is one of the most tested and verified physical theories of all time, present experimental observations are consistent with SM expectations. On the other hand SM can not explain many physical observations: the cosmological observations possibly infer the presence of dark matter which is clearly beyond the SM expectations; the SM Higgs model, while explaining the generation of fermion masses, can not explain the hierarchy problem and a non natural fine tuning of SM is needed to cancel out quadratic divergences in the Higgs boson mass. New physics (NP) beyond SM should hence be investigated: rising the energy above NP processes thresholds, and detecting new particles or new effects not predicted by the standard model directly, is one of the possible approaches; another approach is to make precision measurements of well known processes or looking for rare processes which involve higher order contribution from NP processes, this approach need higher luminosities with respect to the previous approach but lower beam energies. Search for Lepton Flavor Violation (LFV) in charged lepton decays is promising: neutrino physics provides indeed a clear and unambiguous evidence of LFV in the neutral lepton sector via mixing processes, which have been observed …
Date: May 26, 2010
Creator: Cervelli, Alberto
System: The UNT Digital Library
Organic light emitting diodes (OLEDS) and OLED-based structurally integrated optical sensors (open access)

Organic light emitting diodes (OLEDS) and OLED-based structurally integrated optical sensors

General introduction to OLED basics and OLED-based structurally integrated sensors was provided in chapter 1 and chapter 2. As discussed in chapter 3, OLEDs were developed or improved using novel engineering methods for better charge injection (increased by over 1 order of magnitude) and efficiency. As the excitation sources, these OLEDs have preferred characteristics for sensor applications, including narrowed emission, emission at desired wavelength, and enhanced output for reduced EL background, higher absorption and improved device lifetime. In addition to OLEDs with desired performance, sensor integration requires oxidase immobilization with the sensor film for O<sub>2</sub>-based biological and chemical sensing. Nanoparticles such as ZnO have large surface area and high isoelectric point (~9.5), which favors enzyme immobilization via physical adsorption as well as Coulombic bonding. In chapter 4, it was demonstrated that ZnO could be used for this purpose, although future work is needed to further bond the ZnO to the sensor film. In chapter 5, single unit sensor was extended to multianalyte parallel sensing based on an OLED platform, which is compact and integrated with silicon photodiodes and electronics. Lactate and glucose were simultaneously monitored with a low limit of detection 0.02 mM, fast response time (~1 minute) and dynamic …
Date: January 1, 2010
Creator: Cai, Yuankun
System: The UNT Digital Library
A Study of Muon Ionization Cooling at MICE (open access)

A Study of Muon Ionization Cooling at MICE

A Neutrino Factory based on a high-energy muon storage-ring is proposed to study neutrino oscillation with high precision. An emittance reduction of muon beam by ionization cooling, which has never been demonstrated in practice, is one of the critical issues for Neutrino Factory. The international Muon Ionisation Cooling Experiment (MICE) is the first experiment to verify an effect of the ionization cooling with muons. MICE will measure a change in transverse emittance of approximately 10% with a precision of ±0.1%. In order to meet the requirements, muon trackers based on 350 μm diameter scintillating fibers have been proposed. The construction of such trackers is a very challenging task and some innovative techniques are needed to realize, since there have been no trackers made with such a small diameter of scintillating fibers in the world. Upstream and downstream SciFi trackers have been successfully constructed with the international collaboration of UK, US and Japan by 2008. Both of the trackers have been tested with cosmic-rays at the RAL by 2009, at which high tracking efficiencies more than 90% are measured for both trackers. It is also confirmed that by collecting the misalignments found in both of the trackers, the requirements for the …
Date: February 1, 2010
Creator: Sakamoto, Hideyuki
System: The UNT Digital Library
Measurement of the Three-jet Mass Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV (open access)

Measurement of the Three-jet Mass Cross Section in $p\bar{p}$ Collisions at $\sqrt{s}=1.96$ TeV

This thesis describes the measurement of the inclusive three-jet cross section in proton-antiproton collisions at √s = 1.96 TeV measured at the D0 experiment at the Fermilab Tevatron Collider in the Fermi National Accelerator Laboratory, Batavia, Illinois, USA. The cross section as a function of three-jet invariant mass is provided in three regions of the third jet transverse momentum and three regions of jet rapidities. It utilizes a data sample collected in the so called Run IIa data taking period (2002-2006) corresponding to the integrated luminosity of about 0.7 fb<sup>-1</sup>. The results are used to test the next-to-leading order predictions of Quantum chromodynamics computed using the latest parton distribution functions.
Date: June 1, 2010
Creator: Hubacek, Zdenek
System: The UNT Digital Library
Measurement of the absolute v<sub>μ</sub>-CCQE cross section at the SciBooNE experiment (open access)

Measurement of the absolute v<sub>μ</sub>-CCQE cross section at the SciBooNE experiment

This thesis presents the measurement of the charged current quasi-elastic (CCQE) neutrino-nucleon cross section at neutrino energies around 1 GeV. This measurement has two main physical motivations. On one hand, the neutrino-nucleon interactions at few GeV is a region where existing old data are sparse and with low statistics. The current measurement populates low energy regions with higher statistics and precision than previous experiments. On the other hand, the CCQE interaction is the most useful interaction in neutrino oscillation experiments. The CCQE channel is used to measure the initial and final neutrino fluxes in order to determine the neutrino fraction that disappeared. The neutrino oscillation experiments work at low neutrino energies, so precise measurement of CCQE interactions are essential for flux measurements. The main goal of this thesis is to measure the CCQE absolute neutrino cross section from the SciBooNE data. The SciBar Booster Neutrino Experiment (SciBooNE) is a neutrino and anti-neutrino scattering off experiment. The neutrino energy spectrum works at energies around 1 GeV. SciBooNE was running from June 8th 2007 to August 18th 2008. In that period, the experiment collected a total of 2.65 x 10<sup>20</sup> protons on target (POT). This thesis has used full data collection in …
Date: July 1, 2010
Creator: Aunion, Jose Luis Alcaraz
System: The UNT Digital Library
A search for $ZH\rightarrow \mu\mu b \bar{b}$ production at the Tevatron (open access)

A search for $ZH\rightarrow \mu\mu b \bar{b}$ production at the Tevatron

The Standard Model describes with a very good accuracy all interactions of the, so far, known elementary particles. However the Higgs mechanism, which gives rise to the observed mass of these particles, has not yet been confirmed. The Higgs particle has not yet been observed, and the observation or exclusion is an important test of the Standard Model. The Standard Model does not predict the mass of the Higgs particle, however it does impose some limits on the range in which this mass can lie. In direct searches a Higgs with a mass smaller than 114.4 GeV and within 162 GeV and 166 GeV has been excluded at 95% CL at the LEP and the Tevatron colliders. The analysis presented in this thesis is aimed to search for the ZH → μμb$\bar{b}$ events in 3.1 fb<sup>-1</sup> of data collected with the DØ detector in p$\bar{p}$ collisions at √s = 1.96 TeV.
Date: April 20, 2010
Creator: Ancu, Lucian-Stefan
System: The UNT Digital Library
Sum Frequency Generation Vibrational Spectroscopy of Adsorbed Amino Acids, Peptides and Proteins of Hydrophilic and Hydrophobic Solid-Water Interfaces (open access)

Sum Frequency Generation Vibrational Spectroscopy of Adsorbed Amino Acids, Peptides and Proteins of Hydrophilic and Hydrophobic Solid-Water Interfaces

Sum frequency generation (SFG) vibrational spectroscopy was used to investigate the interfacial properties of several amino acids, peptides, and proteins adsorbed at the hydrophilic polystyrene solid-liquid and the hydrophobic silica solid-liquid interfaces. The influence of experimental geometry on the sensitivity and resolution of the SFG vibrational spectroscopy technique was investigated both theoretically and experimentally. SFG was implemented to investigate the adsorption and organization of eight individual amino acids at model hydrophilic and hydrophobic surfaces under physiological conditions. Biointerface studies were conducted using a combination of SFG and quartz crystal microbalance (QCM) comparing the interfacial structure and concentration of two amino acids and their corresponding homopeptides at two model liquid-solid interfaces as a function of their concentration in aqueous solutions. The influence of temperature, concentration, equilibration time, and electrical bias on the extent of adsorption and interfacial structure of biomolecules were explored at the liquid-solid interface via QCM and SFG. QCM was utilized to quantify the biological activity of heparin functionalized surfaces. A novel optical parametric amplifier was developed and utilized in SFG experiments to investigate the secondary structure of an adsorbed model peptide at the solid-liquid interface.
Date: August 1, 2010
Creator: Holinga IV, G.H.
System: The UNT Digital Library
Neutron scattering study of charge-ordering in R1/3Sr2/3FeO3 (R=La, Pr, Nd, Sm, and Y) (open access)

Neutron scattering study of charge-ordering in R1/3Sr2/3FeO3 (R=La, Pr, Nd, Sm, and Y)

The complicated physical phenomena in complex transition-metal oxides (TMO), such as high T<sub>c</sub> superconductivity, colossal magnetoresistivity, metal-insulator transitions, etc., have long been the focus of intense inquiry and debate in condensed matter science, since they are related to strong electronic correlations and cannot be explained within the 'standard model' of solid state physics. These novel functionalities of the correlated electron systems have a wide range of potential for applications in industry, such as information storage, energy transportation, and so on. The charge-ordering (CO) transition is very common in TMO and there is a specific CO transition temperature, TCO. Above TCO, the charge is not ordered, which means that the electrons in a compound are itinerant and the positions of the electrons are not fixed. Below TCO, the charge is ordered, which means that the electrons are localized and the positions of the electrons are settled. Hence, the electrical conductivity of a material is changed at TCO and this transition is classified as metal-insulator transition. Usually the CO with commensurate hole doping in TMO is thought to play an important role in various cases, including the superconducting cuprates, where the spin/charge stripe formation competes with superconducting states, colossal magnetoresistive manganites, where …
Date: January 1, 2010
Creator: Ma, Jie
System: The UNT Digital Library
A search for sterile neutrinos at the MINOS experiment (open access)

A search for sterile neutrinos at the MINOS experiment

MINOS is a long baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory in Illinois, USA. The experiment was designed to study neutrino oscillation phenomena. The {nu}{sub {mu}} beam produced by the NuMI beam facility at FNAL is used along with two functionally identical detectors. The Near Detector at FNAL and a Far Detector 735 km away in the Soudan Underground Laboratory in northern Minnesota. Comparison of the observed spectra of neutrinos at the two detectors provides the evidence for neutrino oscillations. This thesis presents work on the postulated phenomena of sterile neutrinos. Oscillations between active and sterile neutrinos will lead to a deficit in the expected rate of measured Neutral Current interactions at the Far Detector. A technique for selecting Neutral Current events utilizing an Artificial Neural Network is presented with resulting overall efficiency of 91.1% and purity of 66.0%. A method of predicting the expected Charged and Neutral Current energy spectra at the Far Detector given the data recorded at the Near Detector is presented. A model to search for oscillations between sterile and active neutrinos is developed. Sources of systematic uncertainty that can effect the results of the analysis are discussed. The analysis developed is …
Date: August 1, 2010
Creator: Pittam, Robert Neil & U., /Oxford
System: The UNT Digital Library
Sterile neutrino oscillations in MINOS and hadron production in pC collisions (open access)

Sterile neutrino oscillations in MINOS and hadron production in pC collisions

MINOS is a long baseline neutrino oscillation experiment, starting with a muon-neutrino beam, for the precise measurement of the atmospheric neutrino oscillation parameters |{Delta}m{sup 2}| and {theta}{sub 23}. The Near Detector measures the neutrino flux and spectra before oscillations. The beam propagates for 735 km to the Far Detector, which measures the depleted spectrum after oscillations. The depletion can be interpreted as {nu}{sub {mu}} {yields} {nu}{sub {tau}} oscillations. Subdominant {nu}{sub {mu}} {yields} {nu}{sub e} oscillations may be allowed if the mixing angle {theta}{sub 13} {ne} 0. The two detectors are functionally identical in order to cancel systematic errors when using the Near Detector data to constrain the Far Detector prediction. A crucial part of the analysis is the relative calibration between the two detectors, which is known at the 2% level. A calibration procedure to remove the time and temperature dependence of the detector response using through-going cosmic muons is presented here. Although the two-detector approach reduces the systematic uncertainties related to the neutrino flux, a cross check on the neutrino parent meson ratios is performed in this thesis. The cross sections of mesons produced in proton-carbon interactions from the NA49 experiment have been measured and the results have been …
Date: July 1, 2010
Creator: Tinti, Gemma Maria & U., /Oxford
System: The UNT Digital Library
Finding the Higgs boson of the standard model in the channel ZH → e<sup>+</sup>e<sup>-</sup>b$\bar{b}$ with the D0 detector at the Tevatron; Recherche du boson de Higgs du nideke standard dans le canal ZH → e<sup>+</sup>e<sup>-</sup>b$\bar{b}$ Avec le Detecteur DØ Aupres du Tevatron (open access)

Finding the Higgs boson of the standard model in the channel ZH → e<sup>+</sup>e<sup>-</sup>b$\bar{b}$ with the D0 detector at the Tevatron; Recherche du boson de Higgs du nideke standard dans le canal ZH → e<sup>+</sup>e<sup>-</sup>b$\bar{b}$ Avec le Detecteur DØ Aupres du Tevatron

The organization of this thesis consists of three main ideas: the first presents the theoretical framework and experimental, as well as objects used in the analysis and the second relates to the various work tasks of service that I performed on the calorimeter, and the third is the search for the Higgs boson in the channel ZH → e<sup>+</sup>e<sup>-</sup>b$\bar{b}$. Thus, this thesis has the following structure: Chapter 1 is an introduction to the standard model of particle physics and the Higgs mechanism; Chapter 2 is an overview of the complex and the acceleration of the Tevatron at Fermilab DØ detector; Chapter 3 is an introduction to physical objects used in this thesis; Chapter 4 presents the study made on correcting the energy measured in the calorimeter; Chapter 5 describes the study of certification of electrons in the calorimeter; Chapter 6 describes the study of certification of electrons in the intercryostat region of calorimeter; Chapter 7 Detailed analysis on the search for Higgs production in the channel ZH → e<sup>+</sup>e<sup>-</sup>b$\bar{b}$; and Chapter 8 presents the final results of the calculations of upper limits to the production cross section of the Higgs boson on a range of low masses.
Date: June 11, 2010
Creator: Calpas, Betty Constante
System: The UNT Digital Library
Rhodium Catalysts in the Oxidation of CO by O<sub>2</sub> and NO: Shape, Composition, and Hot Electron Generation (open access)

Rhodium Catalysts in the Oxidation of CO by O<sub>2</sub> and NO: Shape, Composition, and Hot Electron Generation

It is well known that the activity, selectivity, and deactivation behavior of heterogeneous catalysts are strongly affected by a wide variety of parameters, including but not limited to nanoparticle size, shape, composition, support, pretreatment conditions, oxidation state, and electronic state. Enormous effort has been expended in an attempt to understand the role of these factors on catalytic behavior, but much still remains to be discovered. In this work, we have focused on deepening the present understanding of the role of nanoparticle shape, nanoparticle composition, and hot electrons on heterogeneous catalysis in the oxidation of carbon monoxide by molecular oxygen and nitric oxide. These reactions were chosen because they are important for environmental applications, such as in the catalytic converter, and because there is a wide range of experimental and theoretical insight from previous single crystal work as well as experimental data on nanoparticles obtained using new state-of-the-art techniques that aid greatly in the interpretation of results on complex nanoparticle systems. In particular, the studies presented in this work involve three types of samples: ~ 6.5 nm Rh nanoparticles of different shapes, ~ 15 nm Rh<sub>1-x</sub>Pd<sub>x</sub> core-shell bimetallic polyhedra nanoparticles, and Rh ultra-thin film (~ 5 nm) catalytic nanodiodes. The colloidal …
Date: March 8, 2010
Creator: Renzas, James R.
System: The UNT Digital Library
Search for the Standard Model Higgs Boson in the $WH \to \ell \nu b\bar{b}$ Channel in 1.96-TeV Proton-Antiproton Collisions (open access)

Search for the Standard Model Higgs Boson in the $WH \to \ell \nu b\bar{b}$ Channel in 1.96-TeV Proton-Antiproton Collisions

We have searched for the Standard Model Higgs boson in the WH → lvbb channel in 1.96 TeV pp collisions at CDF. This search is based on the data collected by March 2009, corresponding to an integrated luminosity of 4.3 fb<sup>-1</sup>. The W H channel is one of the most promising channels for the Higgs boson search at Tevatron in the low Higgs boson mass region.
Date: February 1, 2010
Creator: Nagai, Yoshikazu
System: The UNT Digital Library
Measurement of Single Spin Asymmetries in Semi-Inclusive Deep Inelastic Scattering Reaction n↑ ( e,e' pi{sup +}) X at Jefferson Lab (open access)

Measurement of Single Spin Asymmetries in Semi-Inclusive Deep Inelastic Scattering Reaction n↑ ( e,e' pi{sup +}) X at Jefferson Lab

What constitutes the spin of the nucleon? The answer to this question is still not completely understood. Although we know the longitudinal quark spin content very well, the data on the transverse quark spin content of the nucleon is still very sparse. Semi-inclusive Deep Inelastic Scattering (SIDIS) using transversely polarized targets provide crucial information on this aspect. The data that is currently available was taken with proton and deuteron targets. The E06-010 experiment was performed at Jefferson Lab in Hall-A to measure the single spin asymmetries in the SIDIS reaction n↑(e, e′π{sup ±}/K{sup ±})X using transversely polarized {sup 3}He target. The experiment used the continuous electron beam provided by the CEBAF accelerator with a beam energy of 5.9 GeV. Hadrons were detected in a high-resolution spectrometer in coincidence with the scattered electrons detected by the BigBite spectrometer. The kinematic coverage focuses on the valence quark region, x = 0.19 to 0.34, at Q{sup 2} = 1.77 to 2.73 (GeV/c){sup 2}. This is the first measurement on a neutron target. The data from this experiment, when combined with the world data on the proton and the deuteron, will provide constraints on the transversity and Sivers distribution functions on both the u …
Date: June 1, 2010
Creator: Allada, Kalyan
System: The UNT Digital Library
Extending the frontiers of mass spectrometric instrumentation and methods (open access)

Extending the frontiers of mass spectrometric instrumentation and methods

The focus of this dissertation is two-fold: developing novel analysis methods using mass spectrometry and the implementation and characterization of a novel ion mobility mass spectrometry instrumentation. The novel mass spectrometry combines ion trap for ion/ion reactions coupled to an ion mobility cell. The long term goal of this instrumentation is to use ion/ion reactions to probe the structure of gas phase biomolecule ions. The three ion source - ion trap - ion mobility - qTOF mass spectrometer (IT - IM - TOF MS) instrument is described. The analysis of the degradation products in coal (Chapter 2) and the imaging plant metabolites (Appendix III) fall under the methods development category. These projects use existing commercial instrumentation (JEOL AccuTOF MS and Thermo Finnigan LCQ IT, respectively) for the mass analysis of the degraded coal products and the plant metabolites, respectively. The coal degradation paper discusses the use of the DART ion source for fast and easy sample analysis. The sample preparation consisted of a simple 50 fold dilution of the soluble coal products in water and placing the liquid in front of the heated gas stream. This is the first time the DART ion source has been used for analysis of …
Date: December 15, 2010
Creator: Schieffer, Gregg
System: The UNT Digital Library
Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain (open access)

Immersed Boundary Methods for High-Resolution Simulation of Atmospheric Boundary-Layer Flow Over Complex Terrain

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Date: May 12, 2010
Creator: Lundquist, K A
System: The UNT Digital Library
Electroproduction DE Pions Neutres Dans Le Hall a AU Jefferson Laboratory (open access)

Electroproduction DE Pions Neutres Dans Le Hall a AU Jefferson Laboratory

The past decade has seen a strong evolution of the study of the hadron structure through exclusive processes, allowing to access to a more complete description of this structure. Exclusive processes include DVCS (Deeply Virtual Compton Scattering) as well as hard exclusive meson production. This document is particularly focussed on the latter, and more particularly on exclusive neutral pion production. In this thesis is described the analysis of triple coincidence events H(e, e'{gamma}{gamma})X, which were a consequent by-product of the DVCS experiment which occured during Fall 2004 at Jefferson Lab Hall A, to extract the ep {yields} ep{pi}{sup 0} cross section. This cross section has been measured at two values of four-momentum transfer Q{sup 2} = 1.9 GeV{sup 2} and Q{sup 2} = 2.3 GeV{sup 2}. The statistical precision for these measurements is achieved at better than 5 %. The kinematic range allows to study the evolution of the extracted cross section as a function of Q{sup 2} and W. Results are be confronted with Regge inspired calculations and Generalized (GPD) predictions. An intepretation of our data within the framework of semi-inclusive deep inelastic scattering is also discussed.
Date: June 1, 2010
Creator: Fuchey, Eric
System: The UNT Digital Library
Measurement of ww + wz production cross section and study of the dijet mass spectrum in the lnu + jets final state at CDF (open access)

Measurement of ww + wz production cross section and study of the dijet mass spectrum in the lnu + jets final state at CDF

We present the measurement of the WW and WZ production cross section in p{bar p} collisions at {radical}s = 1.96 TeV, in a final state consisting of an electron or muon, neutrino and jets. The data analyzed were collected by the CDF II detector at the Tevatron collider and correspond to 4.3 fb{sup -1} of integrated luminosity. The analysis uses a fit to the dijet mass distribution to extract the diboson contribution. We observe 1582 {+-} 275(stat.) {+-} 107(syst.) diboson candidate events and measure a cross section of {sigma}{sub WW/WZ} = 18.1 {+-} 3.3(stat.) {+-} 2.5(syst.) pb, consistent with the Standard Model prediction of 15.9 {+-} 0.9 pb. The best fit to the dijet mass of the known components shows a good agreement with the data except for the [120, 160] GeV/c{sup 2} mass range, where an excess is observed. We perform detailed checks of our background model and study the significance of the excess, assuming an additional gaussian component with a width compatible with the expected dijet mass resolution. A standard {Delta}{sub {chi}}{sup 2} test of the presence of the additional component, returns a p-value of 4.2 x 10{sup -4} when standard sources of systematics are considered, corresponding to …
Date: December 1, 2010
Creator: Cavaliere, Viviana & U., /Siena
System: The UNT Digital Library
Measurement of the Ratio of Inclusive Cross Sections !(p-p!Z+b-jet) !(p-p!Z+jet) in the Dilepton Final States (open access)

Measurement of the Ratio of Inclusive Cross Sections !(p-p!Z+b-jet) !(p-p!Z+jet) in the Dilepton Final States

The inclusive production of b-jets with a Z boson is an important background to searches for the Higgs boson in associated ZH {yields} llb{bar b} production at the Fermilab Tevatron collider. This thesis describes the most precise measurement to date of the ratio of inclusive cross sections {sigma}(p{bar p} {yields} Z + b-jet)/{sigma}(p{bar p} {yields} Z + jet) when a Z boson decays into two electrons or muons. The measurement uses a data sample from p{bar p} collisions at the center of mass energy {radical}s = 1.96 TeV corresponding to an integrated luminosity of 4.2 fb{sup -1} collected by the D0 detector. The measured ratio {sigma}(Z + b-jet)/{sigma}(Z + jet) is 0.0187 {+-} 0.0021(stat) {+-} 0.0015(syst) for jets with transverse momentum p{sub T} &gt; 20 GeV and pseudorapidity |{eta}| {le} 2.5. The measurement is compared with the next-to-leading order theoretical predictions from MCFM and is found to be consistent within uncertainties.
Date: October 1, 2010
Creator: Smith, Kenneth James
System: The UNT Digital Library
Using Quasi-Elastic Events to Measure Neutrino Oscillations with MINOS Detectors in the NuMI Neutrino Beam (open access)

Using Quasi-Elastic Events to Measure Neutrino Oscillations with MINOS Detectors in the NuMI Neutrino Beam

MINOS (Main Injector Neutrino Oscillation Search) experiment has been designed to search for a change in the flavor composition of a beam of muon neutrinos as they travel between the Near Detector at Fermi National Accelerator Laboratory and the Far Detector in the Soudan mine in Minnesota, 735 km from the target. The MINOS oscillation analysis is mainly performed with the charged current (CC) events and sensitive to constrain high-{Delta}m{sup 2} values. However, the quasi-elastic (QEL) charged current interaction is dominant in the energy region important to access low-{Delta}m{sup 2} values. For further improvement, the QEL oscillation analysis is performed in this dissertation. A data sample based on a total of 2.50 x 10{sup 20} POT is used for this analysis. In summary, 55 QEL-like events are observed at the Far detector while 87.06 {+-} 13.17 (syst.) events are expected with null oscillation hypothesis. These data are consistent with {nu}{sub {mu}} disappearance via oscillation with {Delta}m{sup 2} = 2.10 {+-} 0.37 (stat.) {+-} 0.24 (syst.) eV{sup 2} and the maximal mixing angle.
Date: May 1, 2010
Creator: Watabe, Masaki & University, /Texas A&M
System: The UNT Digital Library
Measurement of the \textit{CP} Violating Phase $\boldsymbol{\sin(2\beta_{s})}$ using $\boldsymbol{B^{0}_{s}\rightarrow J/\psi\phi}$ Decays at CDF (open access)

Measurement of the \textit{CP} Violating Phase $\boldsymbol{\sin(2\beta_{s})}$ using $\boldsymbol{B^{0}_{s}\rightarrow J/\psi\phi}$ Decays at CDF

A B{sub s}{sup 0} meson can oscillate into its anti-particle, the {bar B}{sub s}{sup 0} meson, before decaying. CP violation in this system is made possible by the presence of amplitudes from both mixed and unmixed B{sub s}{sup 0} meson decays. The CP violating phase {beta}s appears in the interference between the decay amplitudes. The quantity sin(2{beta}s) is expected to be small in the standard model. Thus, measuring a large value for sin(2{beta}s) would be an unequivocal sign of new physics participation in the B{sub s}{sup 0} mixing loop diagram. In this thesis, we present a latest measurement of sin(2{beta}s), using 5.2 fb{sup -1} of data collected at CDF from p{bar p} collisions at a center of mass energy of {radical}s = 1.96 TeV. A time-dependent angular analysis, with the production flavor of the B{sub s}{sup 0} meson identified with flavor tagging methods, is used to extract sin(2{beta}s) from {approx}6500 B{sub s}{sup 0} {yields} J/{psi}{phi} decays. Other parameters of interest, such as the B{sub s}{sup 0} lifetime and the decay width difference {Delta}{Lambda} between the heavy and light B{sub s}{sup 0} mass eigenstates are determined to high precision. Also, the effect of potential contributions to the final state from B{sub …
Date: May 1, 2010
Creator: Pueschel, Elisa
System: The UNT Digital Library
Search for the Standard Model Higgs Boson in p anti-p Interactions with the Decay Mode H --> W+W- --> mu+nu mu-anti-nu at the D0 Experiment (open access)

Search for the Standard Model Higgs Boson in p anti-p Interactions with the Decay Mode H --> W+W- --> mu+nu mu-anti-nu at the D0 Experiment

A search for the standard model Higgs boson in p{bar p} collisions resulting in two muons and large missing transverse energy is presented. The analysis uses 4.2 fb{sup -1} of integrated luminosity at a center-of-mass energy of {radical}s = 1.96 TeV collected between April 2002 and December 2008 with the D0 detector at the Fermilab Tevatron collider. No significant excess above the background estimation is observed and limits are derived on Higgs boson production.
Date: April 1, 2010
Creator: Johnston, Dale Morgan & U., /Nebraska
System: The UNT Digital Library
Measurement and simulations of intensity-dependent effects in the Fermilab Booster Synchrotron (open access)

Measurement and simulations of intensity-dependent effects in the Fermilab Booster Synchrotron

The Fermilab Booster is a nearly 40-year-old proton synchrotron, designed to accelerate injected protons from a kinetic energy of 400 MeV to 8 GeV for extraction into the Main Injector and ultimately the Tevatron. Currently the Booster is operated with a typical intensity of 4.5 x 10{sup 12} particles per beam, roughly twice the value of its design, because of the requirement for high particle flux in various experiments. Its relatively low injection energy provides certain challenges in maintaining beam quality and stability under these increasing intensity demands. An understanding of the effects limiting this intensity could provide enhanced beam stability and reduced downtime due to particle losses and subsequent damage to the accelerator elements. Design of future accelerators can also benefit from a better understanding of intensity effects limiting injection dynamics. Chapter 1 provides a summary of accelerator research during the 20th century leading to the development of the modern synchrotron. Chapter 2 puts forth a working knowledge of the terminology and basic theory used in accelerator physics, and provides a brief description of the Fermilab Booster synchrotron. Synergia, a 3d space-charge modeling framework, is presented, along with some simulation benchmarks relevant to topics herein. Emittance, a commonly used …
Date: December 1, 2010
Creator: McCarron, Daniel O.
System: The UNT Digital Library
Microstructures and oxidation behavior of some Molybdenum based alloys (open access)

Microstructures and oxidation behavior of some Molybdenum based alloys

The advent of Ni based superalloys revolutionized the high temperature alloy industry. These materials are capable of operating in extremely harsh environments, comprising of temperatures around 1050 C, under oxidative conditions. Demands for increased fuel efficiency, however, has highlighted the need for materials that can be used under oxidative conditions at temperatures in excess of 1200 C. The Ni based superalloys are restricted to lower temperatures due to the presence of a number of low melting phases that melt in the 1250 - 1450 C, resulting in softening of the alloys above 1000 C. Therefore, recent research directions have been skewed towards exploring and developing newer alloy systems. This thesis comprises a part of such an effort. Techniques for rapid thermodynamic assessments were developed and applied to two different systems - Mo-Si alloys with transition metal substitutions (and this forms the first part of the thesis) and Ni-Al alloys with added components for providing high temperature strength and ductility. A hierarchical approach towards alloy design indicated the Mo-Ni-Al system as a prospective candidate for high temperature applications. Investigations on microstructures and oxidation behavior, under both isothermal and cyclic conditions, of these alloys constitute the second part of this thesis. It …
Date: December 15, 2010
Creator: Ray, Pratik Kumar
System: The UNT Digital Library