Measurement of the w and z cross sections in the electron channel for p anti-p collisions at s**(1/2) = 1.96 TeV and extraction of the w total width from the ratio (open access)

Measurement of the w and z cross sections in the electron channel for p anti-p collisions at s**(1/2) = 1.96 TeV and extraction of the w total width from the ratio

This dissertation presents measurements of the inclusive production cross sections for W and Z gauge bosons decaying through the electron channel with p{bar p} collisions at a center-of-mass energy of 1.96 TeV. The ratio of these cross sections is then used to extract the W total width. The Standard Model (SM) of electroweak and strong interactions is a collection of theories which together encompass what is currently known about the elementary particles that make up matter and the forces through which they interact. Experimentalists are constantly searching for violations of the Standard Model by making precision measurements of predicted interactions. The decay of the W boson is one such interaction. The rate of its decay is reflected in its width which is predicted to high precision using Standard Model-based calculations. Therefore, a high precision experimental width measurement would be very sensitive to any such violation. In principle the W and Z boson production cross sections could also be good Standard Model tests. However, a precise knowledge of integrated luminosity is required which is unfortunately difficult to obtain at the Tevatron. In fact, the W and Z cross section results can be used to obtain a more precise luminosity measurement. The …
Date: January 1, 2005
Creator: Gardner, John Michael
System: The UNT Digital Library
MAGNETIC PROPERTIES OF HIGH PURITY SCANDIUM, YTTRIUM, LANTHANUM AND LUTETIUM AND THE EFFECTS OF IMPURITIES ON THESE PROPERTIES. (open access)
Mechanics of Metals with Phase Changes (open access)

Mechanics of Metals with Phase Changes

New experimental data is presented on some exotic metals that exhibit phase changes at cryogenic temperatures. The types of phase changes that were detected in the specific heat data range from martensitic (diffusion less) transitions to superconducting transitions. In addition, the charge density wave (CDW) state in uranium metal was detected in the specific heat. Specific-heat measurements were made in zero-magnetic field using an apparatus capable of obtaining temperatures as low as 0.4 K. Calibration performed on this apparatus, using a single-crystal copper sample, show its accuracy to be 0.50%, while the resolution was better than 0.1%. Our measurements demonstrate that similar high precision and accurate specific-heat measurements can be obtained on milligram-scale samples. In Chapters 2 and 3, specific-heat measurements are presented for the B2 (CsCl structure) alloy AuZn and for {alpha}-uranium (orthorhombic symmetry). The AuZn alloy exhibits a continuous transition at 64.75 K and an entropy of transition of ({Delta}S{sub tr}) 2.02 J K{sup {minus}1} mol{sup {minus}1}. Calculation of the Debye temperature, by extrapolating of the high temperature phase elastic constants to T = 0 K yields a value of 207 K ({+-}2 K), in favorable agreement with the calorimetric value of 219 K ({+-}0.50 K), despite the …
Date: January 1, 2001
Creator: Lashley, J.C.
System: The UNT Digital Library
Solution based synthesis of perovskite-type oxide films and powders (open access)

Solution based synthesis of perovskite-type oxide films and powders

Conventional solid state reactions are diffusion limited processes that require high temperatures and long reaction times to reach completion. In this work, several solution based methods were utilized to circumvent this diffusion limited reaction and achieve product formation at lower temperatures. The solution methods studied all have the common goal of trapping the homogeneity inherent in a solution and transferring this homogeneity to the solid state, thereby creating a solid atomic mixture of reactants. These atomic mixtures can yield solid state products through diffusionless mechanisms. The effectiveness of atomic mixtures in solid state synthesis was tested on three classes of materials, varying in complexity. A procedure was invented for obtaining the highly water soluble salt, titanyl nitrate, TiO(NO{sub 3}){sub 2}, in crystalline form, which allowed the production of titanate materials by freeze drying. The freeze drying procedures yielded phase pure, nanocrystalline BaTiO{sub 3} and the complete SYNROC-B phase assemblage after ten minute heat treatments at 600 C and 1,100 C, respectively. Two novel methods were developed for the solution based synthesis of Ba{sub 2}YCu{sub 3}O{sub 7{minus}x} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10}. Thin and thick films of Ba{sub 2}YCu{sub 3}O{sub 7{minus}x} and Bi{sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub 10} were …
Date: January 1, 1995
Creator: McHale, J. M. Jr.
System: The UNT Digital Library
A Study of the Kinetic and Mechanical Properties of a Stabilized Beta Phase Plutonium Alloy (open access)

A Study of the Kinetic and Mechanical Properties of a Stabilized Beta Phase Plutonium Alloy

The elements Sn, Mg, Ti, Zr, Hf, Si, Cd, and U were alloyed with plutonium to determine their effect on stabilization of the beta phase. Zirconium was found to be the ' most effective. Kinetic studies were conducted on Pu-Zr alloys having 0.24, 0.65, and 1.7 at.% Zr contents. The beta to alpha transformation in the Pu-Zr alloys was somewhat similar to that in unalloyed plutonium. The main difference being that time, temperature, transformation curves of the alloys were shifted to the right as the zirconium concentration increased. It was determined that the amount of beta phase retained at room temperature increased as the zirconium concentration increased. The minimum amount of Zr needed to stabilize the beta phase of plutonium at room temperature was determined to be 2.0 at.%. A 2.4 at.% Zr addition stabilized the beta phase of plutonium at atmospheric pressure from room temperature to 265 deg C. During mechanical property testing it was determined that the stabilized beta Pu-2.4 at.% Zr alloy was brittle from room temperature to 230 deg C. Both tensile and compression strengths of the beta stabilized alloy were greater than the unalloyed beta phase of plutonium. A brittle-ductile transition was noted between 130 …
Date: January 1, 1962
Creator: Taylor, J. M.
System: The UNT Digital Library
OPTIMAL DIGITAL COMPUTER CONTROL OF NUCLEAR REACTORS. (open access)

OPTIMAL DIGITAL COMPUTER CONTROL OF NUCLEAR REACTORS.

None
Date: January 1, 1969
Creator: Lipinski, W C
System: The UNT Digital Library
High temperature vapor pressure and the critical point of potassium (open access)

High temperature vapor pressure and the critical point of potassium

The vapor pressure was determined from 1600 deg F up to the critical point. The equation Ln P = A + B/T + C Ln T was found to fit the data well, a fourth term D/T/sup 2/ further improved the fit. A novel design was employed in measuring the vapor pressure, which provides a direct determination of the critical pressure, because at all tip temperatures higher than the critical temperature the same breakoff pressure'' is observed. This breakoff'' pressure'', which is produced when the liquid level reaches the critical temperature in its travel along the bore of the tube, is the critical pressure. (58 figures, 50 references) (DLC)
Date: January 1, 1972
Creator: Jerez, W. R. & Bonilla, C. F.
System: The UNT Digital Library
Photoproduction of the K+ K0-(1750) (open access)

Photoproduction of the K+ K0-(1750)

While photoproduction has often been advertised as an important environment in which to study light meson spectroscopy, solid experimental results are sparse. In fact, beyond the relatively straightforward photoproduction of the {rho}, {omega}, and {phi} mesons, the few results of exclusive photoproduction that do exist are poorly understood, and several, perhaps, have even been misinterpreted. After extensively reviewing the sometimes tenuous history of the exclusive photoproduction of the ''{rho}{sup 1}(1600)'', the ''{omega}{pi}{sup 0}(1250)'', the ''{omega}(1650)'', and the ''K{sup +}K{sup -}(1750)'', new results from the E831/FOCUS photoproduction experiment at Fermilab are presented which address the interpretation of the K{sup +}K{sup -}(1750). This enhancement in low-p{sub T} K{sup +}K{sup -} pairs at a mass near 1750 MeV/c{sup 2} has been observed by several previous photoproduction experiments, but, despite several apparent inconsistencies, it has always been interpreted as the J{sup PC} = 1{sup --} {phi}(1680) meson. With nearly two orders of magnitude more events than any previous observation of the K{sup +}K{sup -}(1750), and based on precise measurements of its mass and width, and its absence from the K*K final state, the FOCUS data can finally render this interpretation implausible. In addition, several steps have been taken towards establishing a new interpretation. Based …
Date: January 1, 2003
Creator: Mitchell, Ryan Edward & U., /Tennessee
System: The UNT Digital Library
Static equilibria of the interstellar gas in the presence of magnetic and gravitational fields (open access)

Static equilibria of the interstellar gas in the presence of magnetic and gravitational fields

None
Date: January 1, 1975
Creator: Mouschovias, T.C.
System: The UNT Digital Library
GLASS BEADS IN AFRICAN ARCHAEOLOGY: RESULTS OF NEUTRON ACTIVATION ANALYSIS, SUPPLEMENTED BY RESULTS OF X-RAY FLUORESCENCE ANALYSIS. (open access)
STABILITY OF THE GUIDING CENTER PLASMA. (open access)

STABILITY OF THE GUIDING CENTER PLASMA.

None
Date: January 1, 1968
Creator: Nelson, David B.
System: The UNT Digital Library
BIOPHYSICAL STUDIES OF SPERMATOZOA. (open access)

BIOPHYSICAL STUDIES OF SPERMATOZOA.

None
Date: January 1, 1970
Creator: Pistenma, D.A.
System: The UNT Digital Library
TIGHT-BINDING ENERGY BANDS OF PEROVSKITE TYPE TRANSITION METAL OXIDES. (open access)

TIGHT-BINDING ENERGY BANDS OF PEROVSKITE TYPE TRANSITION METAL OXIDES.

None
Date: January 1, 1969
Creator: Karian, H G
System: The UNT Digital Library
LOW-FREQUENCY WAVES, STABILIZATION, AND ENHANCED TRANSPORT IN THE PLASMA SURROUNDING A HOLLOW CATHODE DISCHARGE. (open access)

LOW-FREQUENCY WAVES, STABILIZATION, AND ENHANCED TRANSPORT IN THE PLASMA SURROUNDING A HOLLOW CATHODE DISCHARGE.

None
Date: January 1, 1972
Creator: Wheeler, G. M.
System: The UNT Digital Library
TWO-PROTON FINAL-STATE INTERACTIONS IN THE REACTIONS $sup 3$He(d,t)2p, d($sup 3$He,t)2p, $sup 3$He($sup 3$He,$sup 4$He)2p, AND p($sup 3$He,d)2p. (open access)
Investigation of Fast Neutron Radiation Damage in an Austenitic Stainless Steel. (open access)

Investigation of Fast Neutron Radiation Damage in an Austenitic Stainless Steel.

None
Date: January 1, 1970
Creator: Bloom, E. E.
System: The UNT Digital Library
NEUTRON SPECTRA EMITTED BY $sup 239$Pu, $sup 238$U, $sup 235$U, Pb, Nb, Ni, Al, AND C IRRADIATED BY 14-MeV NEUTRONS. (open access)

NEUTRON SPECTRA EMITTED BY $sup 239$Pu, $sup 238$U, $sup 235$U, Pb, Nb, Ni, Al, AND C IRRADIATED BY 14-MeV NEUTRONS.

None
Date: January 1, 1972
Creator: Kammerdiener, John Luther
System: The UNT Digital Library
The use of ultraviolet Thomson scattering as a versatile diagnostic for detailed measurements of a collisional laser produced plasma (open access)

The use of ultraviolet Thomson scattering as a versatile diagnostic for detailed measurements of a collisional laser produced plasma

Collective Thomson scattering from ion-acoustic waves at 266nm is used to obtain spatially resolved, two-dimensional electron density, sound speed, and radial drift profiles of a collisional laser plasma. An ultraviolet diagnostic wavelength minimizes the complicating effects of inverse bremsstrahlung and refractive turning in the coronal region of interest, where the electron densities approach n{sub c}/10. Laser plasmas of this type are important because they model some of the aspects of the plasmas found in high-gain laser-fusion pellets irradiated by long pulse widths where the laser light is absorbed mostly in the corona. The experimental results and LASNEX simulations agree within a percent standard deviation of 40% for the electron density and 50% for the sound speed and radial drift velocity. Thus it is shown that the hydrodynamics equations with classical coefficients and the numerical approximations in LASNEX are valid models of laser-heated, highly collisional plasmas. The versatility of Thomson scattering is expanded upon by extending existing theory with a Fokker-Planck based model to include plasmas that are characterized by (0 {le} k{sub ia}{lambda}{sub ii} {le} {infinity}) and ZT{sub e}/T{sub i}, where k{sub ia} is the ion- acoustic wave number, {lambda}{sub ii} is the ion-ion mean free path, Z is the …
Date: January 8, 1993
Creator: Tracy, M. D.
System: The UNT Digital Library
Some calorimetric investigations of the role of electrons in superconductivity and magnetism (open access)

Some calorimetric investigations of the role of electrons in superconductivity and magnetism

Thesis. The heat capacity of the system (La,Ce)Al//sub 2/ for 0.0, 0.193, 0.64, and 0.906 at.% Ce has been measured between approximately 0.06 and 22 K and in magnetic fields up to 38 kOe. In the normal state, there is R1n2 entropy associated wtih the Ce spin system and this entropy is removed in the formation of the spin-compensated state. The nonmal state Kondo temperature is 0.42 K. The three more-dilute samples exhibit supenconductivity but cannot be described by the Bardeen - Cooper -- Schrieffer on Abrlkosov -Gor'kov theories. Significant low-energy excitations are evident in the superconducting state and they may be associated with quasibound states deep in the energy gap of the pure superconductor. Fon the 0.193 at.% Ce alloy in the superconducting state the characteristic temperature associated with Ce-spin ordering in the nonmal state is reduced by an estimated order of magnitude. For the 0.64 at.% Ce alloy a small, broadened superconducting anomaly appears in the heat capacity above 1 K, however, no anomaly that could be interpreted as a broadened discontinuity was found at the magnetically-detected transition back into the normal state at lower temperatures. The heat capacities of five samples of alpha -U have been measured …
Date: January 1, 1974
Creator: Bader, Samuel David
System: The UNT Digital Library
SOIL WATER REDISTRIBUTION DURING EVAPORATION. (open access)

SOIL WATER REDISTRIBUTION DURING EVAPORATION.

None
Date: January 1, 1968
Creator: Fritton, D.D.
System: The UNT Digital Library
Atomic and Molecular Photoelectron and Auger Electron SpectroscopyStudies Using Synchrotron Radiation (open access)

Atomic and Molecular Photoelectron and Auger Electron SpectroscopyStudies Using Synchrotron Radiation

Electron spectroscopy, combined with synchrotron radiation, was used to measure the angular distributions of photoelectrons and Auger electrons from atoms and molecules as functions of photon energy. The branching ratios and partial cross sections were a 130 measured in certain cases. By comparison with theoretical calculations, the experimental results are interpreted in terms of the characteristic electronic structure and ionization dynamics of the atomic or molecular sample. The time structure of the synchrotron radiation source was used to record time-of-flight (TOF) spectra o f the ejected electrons. The ''a double-angle-TOF'' method for the measurement of photoelectron angular distributions is discussed. This technique offers the advantages of increased electron collect ion efficiency and the elimination of certain systematic errors. Several results were obtained for Xe using photon energies in the range hv {approx_equal} 60-190 eV, where excitation and ionization of the inner-subshell 4d electrons dominates. The 4d asymmetry parameter {beta} exhibits strong oscillations with energy, in agreement with several theoretical calculations. As predicted, the 5p asymmetry parameter was observed to deviate strongly from that calculated using the independent-electron model, due to intershell correlation with the 4d electrons.
Date: January 1, 1982
Creator: Southworth, Stephen H.
System: The UNT Digital Library
Determination of saccharides and ethanol from biomass conversion using Raman spectroscopy:  Effects of pretreatment and enzyme composition (open access)

Determination of saccharides and ethanol from biomass conversion using Raman spectroscopy: Effects of pretreatment and enzyme composition

This dissertation focuses on the development of facile and rapid quantitative Raman spectroscopy measurements for the determination of conversion products in producing bioethanol from corn stover. Raman spectroscopy was chosen to determine glucose, xylose and ethanol in complex hydrolysis and fermentation matrices. Chapter 1 describes the motives and main goals of this work, and includes an introduction to biomass, commonly used pretreatment methods, hydrolysis and fermentation reactions. The principles of Raman spectroscopy, its advantages and applications related to biomass analysis are also illustrated. Chapter 2 and 3 comprise two published or submitted manuscripts, and the thesis concludes with an appendix. In Chapter 2, a Raman spectroscopic protocol is described to study the efficiency of enzymatic hydrolysis of cellulose by measuring the main product in hydrolysate, glucose. Two commonly utilized pretreatment methods were investigated in order to understand their effect on glucose measurements by Raman spectroscopy. Second, a similar method was set up to determine the concentration of ethanol in fermentation broth. Both of these measurements are challenged by the presence of complex matrices. In Chapter 3, a quantitative comparison of pretreatment protocols and the effect of enzyme composition are studied using systematic methods. A multipeak fitting algorithm was developed to …
Date: January 1, 2010
Creator: Shih, Chien-Ju
System: The UNT Digital Library
Study of the doubly and singly Cabibbo suppressed decays D+ --> K+ pi- pi+ and D(s)+ --> K+ pi- pi+ in the FOCUS experiment (open access)

Study of the doubly and singly Cabibbo suppressed decays D+ --> K+ pi- pi+ and D(s)+ --> K+ pi- pi+ in the FOCUS experiment

This thesis illustrates a complete study of the doubly and singly Cabibbo suppressed decays D{sup +} and D{sub s}{sup +} {yields} K{sup +} {pi}{sup -}{pi}{sup +}. Data for this analysis have been collected by the fixed-target high-energy photoproduction experiment FOCUS at Fermilab. The authors have selected the D{sup +} and D{sub s}{sup +} samples with cuts to obtain a sufficiently high statistics, a good signal to noise ratio and, at the same time, eliminate possible contaminations from the more copious and favored decays. The D{sup +} yield consists of 189 {+-} 24 events, with a signal to noise ratio {approx} 1; the D{sub s}{sup +} yield is 567 {+-} 31 and the signal to noise ratio is {approx} 2.5. The authors have measured {Lambda}(D{sup +} {yields} K{sup +}{pi}{sup -}{pi}{sup +})/{Lambda}(D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +}) = 0.0065 {+-} 0.0008 {+-} 0.004 and {Lambda}(D{sub s}{sup +} {yields} K{sup +}{pi}{sup -}{pi}{sup +})/{Lambda}(D{sub s}{sup +} {yields} K{sup +}K{sup -}{pi}{sup +}) = 0.127 {+-} 0.007 {+-} 0.014, improving the previous determinations of a factor of 2 and 5, respectively. The author has also performed a Dalitz plot analysis for both decays. The amplitude analysis for D{sub s}{sup +} {yields} K{sup +}{pi}{sup -}{pi}{sup +} …
Date: January 1, 2005
Creator: Edera, Laura & U., /Milan
System: The UNT Digital Library
Search for the single top quarks produced in s-channel via electroweak interactions at s = 1-96 at the Tevatron (open access)

Search for the single top quarks produced in s-channel via electroweak interactions at s = 1-96 at the Tevatron

The authors present a search for single top quarks produced in the s-channel electroweak production mode. The search is performed in the electron+jets decay channels, with one or more secondary-vertex tagged jets to indicate the presence of a b-jet and hence improving the signal:background ratio. Separation between signal and background is further enhanced by the use of Feed Forward Neural networks. 360 pb{sup -1} of Run II data used for this analysis was delivered by the Tevatron, and collected by D0 between August 2002 and August 2004. The resulting 95% confidence level upper limit is 4 pb.
Date: January 1, 2006
Creator: Jabeen, Shabnam
System: The UNT Digital Library