A search for W+- H ---> muon-neutrino b anti-b production at the Tevatron (open access)

A search for W+- H ---> muon-neutrino b anti-b production at the Tevatron

All known experimental results on fundamental particles and their interactions can be described to great accuracy by a theory called the Standard Model. In the Standard Model of particle physics, the masses of particles are explained through the Higgs mechanism. The Higgs boson is the only Standard Model particle not discovered yet, and its observation or exclusion is an important test of the Standard Model. While the Standard Model predicts that a Higgs boson should exist, it does not exactly predict its mass. Direct searches have excluded a Higgs with m{sub H} < 114.4 GeV at 95% confidence level, while indirect measurements indicate that the mass should be less than 144 GeV. This analysis looks for W{sup {+-}}H {yields} {mu}{nu}{sub {mu}}b{bar b} in 1 fb{sup -1} of data collected with the D0 detector in p{bar p} collisions with {radical}s = 1.96 TeV. The analysis strategy relies on the tracking, calorimetry and muon reconstruction of the D0 experiment. The signature is a muon, missing transverse energy (E{sub T}) to account for the neutrino and two b-jets. The Higgs mass is reconstructed using the invariant mass of the two jets. Backgrounds are W{sup {+-}}b{bar b}, W{sup {+-}} c{bar c}, W{sup {+-}} + …
Date: February 1, 2008
Creator: Anastasoaie, Carmen Miruna & U., /Nijmegen
System: The UNT Digital Library
The Effect of Auditor Knowledge on Information Processing during Analytical Review (open access)

The Effect of Auditor Knowledge on Information Processing during Analytical Review

Auditors form judgments by integrating the evidence they gather with information stored in memory (knowledge). As they acquire experience, auditors have the opportunity to learn how different patterns of evidence are associated with particular audit problems. Research in experimental psychology has demonstrated that individuals with task-specific experience can match the cues they encounter with patterns they have learned, and form judgments without consciously analyzing the individual cues. Accounting researchers have suggested that auditors develop judgment templates through task-specific experience, and that these knowledge structures automatically provide decisions in familiar situations. I examined whether auditor knowledge leads to reliance on judgment templates. To test this thesis, I synthesized a theoretical framework and developed research hypotheses that predict relationships between task-specific experience (my surrogate for knowledge) and (1) measures of cognitive effort, (2) accuracy of residual memory traces, and (3) performance with respect to identifying potential problems. To test these predictions, I provided senior auditors with comprehensive case materials for a hypothetical client and asked them to use analytical procedures to identify potential audit problems. Subjects acquired information and documented their findings on personal computers using software that I developed to record their activities.
Date: February 1995
Creator: O'Donnell, Ed
System: The UNT Digital Library
Speciation of chromium and manganese using pneumatically assisted electrospray mass spectrometry (open access)

Speciation of chromium and manganese using pneumatically assisted electrospray mass spectrometry

It is not an exaggeration to say that much of chemistry involves ions in solution. A technique which allows for ions to be transferred from solution into the gas phase and subsequently analyzed by mass spectrometric detection would be of importance. If structural information, representative of the solution chemistry could be gained from these gas-phase ions, this would also be important. Electrospray mass spectrometry (ES-MS) is such a technique.
Date: February 1, 1997
Creator: Gwizdala, A.B. III
System: The UNT Digital Library
An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion (open access)

An experimental investigation of stimulated Brillouin scattering in laser-produced plasmas relevant to inertial confinement fusion

Despite the apparent simplicity of controlled fusion, there are many phenomena which have prevented its achievement. One phenomenon is laser-plasma instabilities. An investigation of one such instability, stimulated Brillouin scattering (SBS), is reported here. SBS is a parametric process whereby an electromagnetic wave (the parent wave) decays into another electromagnetic wave and an ion acoustic wave (the daughter waves). SBS impedes controlled fusion since it can scatter much or all of the incident laser light, resulting in poor drive symmetry and inefficient laser-plasma coupling. It is widely believed that SBS becomes convectively unstable--that is, it grows as it traverses the plasma. Though it has yet to be definitively tested, convective theory is often invoked to explain experimental observations, even when one or more of the theory`s assumptions are violated. In contrast, the experiments reported here not only obeyed the assumptions of the theory, but were also conducted in plasmas with peak densities well below quarter-critical density. This prevented other competing or coexisting phenomena from occurring, thereby providing clearly interpretable results. These are the first SBS experiments that were designed to be both a clear test of linear convective theory and pertinent to controlled fusion research. A crucial part of this …
Date: February 11, 1993
Creator: Bradley, K. S.
System: The UNT Digital Library
Sum-Frequency Generation from Chiral Media and Interfaces (open access)

Sum-Frequency Generation from Chiral Media and Interfaces

Sum frequency generation (SFG), a second-order nonlinear optical process, is electric-dipole forbidden in systems with inversion symmetry. As a result, it has been used to study chiral media and interfaces, systems intrinsically lacking inversion symmetry. This thesis describes recent progresses in the applications of and new insights into SFG from chiral media and interfaces. SFG from solutions of chiral amino acids is investigated, and a theoretical model explaining the origin and the strength of the chiral signal in electronic-resonance SFG spectroscopy is discussed. An interference scheme that allows us to distinguish enantiomers by measuring both the magnitude and the phase of the chiral SFG response is described, as well as a chiral SFG microscope producing chirality-sensitive images with sub-micron resolution. Exploiting atomic and molecular parity nonconservation, the SFG process is also used to solve the Ozma problems. Sum frequency vibrational spectroscopy is used to obtain the adsorption behavior of leucine molecules at air-water interfaces. With poly(tetrafluoroethylene) as a model system, we extend the application of this surface-sensitive vibrational spectroscopy to fluorine-containing polymers.
Date: February 13, 2006
Creator: Ji, Na
System: The UNT Digital Library
The Relationships Among Self-Esteem, Marital Communication, and Marital Adjustment (open access)

The Relationships Among Self-Esteem, Marital Communication, and Marital Adjustment

This investigation seeks to determine the correlations among the three factors of self-esteem, marital communication and marital adjustment to determine if these factors are evidenced similarly in the marital system, and to determine if their relationships are consistent among a wide range of marriages. In addition, several demographic variables are isolated in order to determine their influence on the three factors under investigation. Based on the findings of the study, it was concluded that marital adjustment is dependent on married individuals' level of self-esteem and the ability to communicate effectively. It was also concluded that when there is a high level of either self-esteem, marital communiation, or marital adjustment, the other factors will also be at a high level. In addition, the consistency of the relationships among marital adjustment, marital communication, and self-esteem apparently transcend demographic factors.
Date: February 1980
Creator: Carter, Warren Leslie
System: The UNT Digital Library
Study of the S-wave K(pi) --> Amplitude Using the Decay D+ --> K-pi+pi+ (open access)

Study of the S-wave K(pi) --> Amplitude Using the Decay D+ --> K-pi+pi+

In this work the S-wave component of the K{pi} amplitude from decay of D{sup +} {yields} K{sup -}{pi}{sup +}{pi}{sup +} it is directly measured. The data come from the Fermilab E831/FOCUS experiment. The amplitude measurement is made using the partial wave analysis without any preliminary assumption about the nature of the S-wave component of the K{pi} system. The phase and magnitude of the S-wave amplitude are generic functions to be determined directly through the Dalitz plot fit. For the sake of comparison, our results the same decay is analyzed using the isobar model, which is the standard way to analyze the Dalitz plot. The data fit obtained with the partial wave analysis is better than the data fit from the isobar model. The phase variation with respect to the invariant mass K{pi} is compared with the measurement of the phase {delta}{sub I=1/2}{sup 0} (m{sub K{pi}}) from K{pi} {yields} K{pi} scattering. The difference between both analysis is discussed considering: a difference in the composition of the isospin components I = 1/2 and I = 3/2 of the K{pi} system between D{sup +} decay and the K{pi} {yields} K{pi} scattering; and the final state interaction involving all particles from decay.
Date: February 1, 2007
Creator: Machado, Ana Amelia Bergamini
System: The UNT Digital Library