Multivariate searches for single top quark production with the D0 detector (open access)

Multivariate searches for single top quark production with the D0 detector

We present a search for electroweak production of single top quarks in (p{bar p} {yields} t{bar b} + X) and t-channel (p{bar p} {yields} tq{bar b} + X) modes. We have analyzed 230 pb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider at a center-of-mass energy of {radical}s = 1.96 TeV. Two separate analysis methods are used: neural networks and a cut-based analysis. No evidence for a single top quark signal is found. We set 95% confidence level upper limits on the production cross sections using Bayesian statistics, based on event counts and binned likelihoods formed from the neural network output. The limits from the neural network (cut-based) analysis are 6.4 pb (10.6 pb) in the s-channel and 5.0 pb (11.3 pb) in the t-channel.
Date: April 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
A Precise measurement of the B0(s) lifetime (open access)

A Precise measurement of the B0(s) lifetime

The authors report a measurement of the B{sub s}{sup 0} lifetime in the semileptonic decay channel B{sub s}{sup 0} {yields} D{sub s}{sup -}{mu}{sup +}{nu}X (and its charge conjugate), using approximately 0.4 fb{sup -1} of data collected with the D0 detector during 2002-2004. They have reconstructed 5176 D{sub s}{sup -} {mu}{sup +} signal events, where the D{sub s}{sup -} is identified via the decay D{sub s}{sup 0} {yields} {phi}{pi}{sup -}, followed by {phi} {yields} K{sup +}K{sup -}. Using these events, they have measured the B{sub s}{sup 0} lifetime to be {tau}(B{sub s}{sup 0}) = 1.398 {+-} 0.044 (stat){sub -0.025}{sup +0.028}(syst) ps. This is the most precise measurement of the B{sub s}{sup 0} lifetime to date.
Date: April 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Search for excited muons in p anti-p collisions at s**(1/2) = 1.96- TeV (open access)

Search for excited muons in p anti-p collisions at s**(1/2) = 1.96- TeV

We present the results of a search for the production of an excited state of the muon, {mu}*, in proton antiproton collisions at {radical}s = 1.96 TeV. The data have been collected with the D0 experiment at the Fermilab Tevatron Collider and correspond to an integrated luminosity of approximately 380 pb{sup -1}. We search for {mu}* in the process p{bar p} {yields} {mu}*{nu}, with the {mu}* subsequently decaying to a muon plus photon. No excess above the standard model expectation is observed in data. Interpreting our data in the context of a model that describes {mu}* production by four-fermion contact interactions and {mu}* decay via electroweak processes, we exclude production cross sections higher than 0.057 pb-0.112 pb at the 95% confidence level, depending on the mass of the excited muon. Choosing the scale for contact interactions to be {Lambda} = 1 TeV, excited muon masses below 618 GeV are excluded.
Date: April 1, 2006
Creator: Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type: Article
System: The UNT Digital Library
Measurement of direct photon emission in the K(L) ---> pi+ pi- gamma decay mode (open access)

Measurement of direct photon emission in the K(L) ---> pi+ pi- gamma decay mode

In this paper the KTeV collaboration reports the analysis of 112.1 x 10{sup 3} candidate K{sub L} {yields} {pi}{sup +}{pi}{sup -}{gamma} decays including a background of 671 {+-} 41 events with the objective of determining the photon production mechanisms intrinsic to the decay process. These decays have been analyzed to extract the relative contributions of the Cp violating bremsstrahlung process and the CP conserving M1 and CP violating E1 direct photon emission processes. The M1 direct photon emission amplitude and its associated vector form factor parameterized as |{bar g}{sub M1}|(1 + a{sub 1}/a{sub 2}/(M{sub {rho}}{sup 2}-M{sub K}{sup 2}) + 2M{sub K}E{sub {gamma}}) have been measured to be |{bar g}{sub M1}| = 1.198 {+-} 0.035(stat) {+-} 0.086(syst) and a{sub 1}/a{sub 2} = =0.738 {+-} 0.007(stat) {+-} 0.018(syst) GeV{sup 2}/c{sup 2} respectively. An upper limit for the CP violating E1 direct emission amplitude |g{sub E1}| {le} 0.1 (90%CL) has been found. The overall ratio of direct photon emission (DE) to total photon emission including the bremsstrahlung process (IB) has been determined to be DE/(DE + IB) = 0.689 {+-} 0.021 for E{sub {gamma}} {ge} 20 MeV.
Date: April 1, 2006
Creator: Abouzaid, E.; Arenton, M.; Barker, A. R.; Bellantoni, L.; Bellavance, A.; Blucher, E. et al.
Object Type: Article
System: The UNT Digital Library
Search for Large Extra Dimensions in the Production of Jets and Missing Transverse Energy in ppbar Collisions at s**(1/2) = 1.96 TeV (open access)

Search for Large Extra Dimensions in the Production of Jets and Missing Transverse Energy in ppbar Collisions at s**(1/2) = 1.96 TeV

The authors present the results of a search for new physics in the jets plus missing transverse energy data sample collected from 368 pb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV recorded by the Collider Detector at Fermilab. They compare the number of events observed in the data with a data-based estimate of the standard model backgrounds contributing to this signature. They observe no significant excess of events, and they interpret this null result in terms of lower limits on the fundamental Planck scale for a large extra dimensions scenario.
Date: April 1, 2006
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, T.; Akimoto, T.; Albrow, M.G. et al.
Object Type: Article
System: The UNT Digital Library
Experimental determination of drag coefficients in low-density polyurethane foam (open access)

Experimental determination of drag coefficients in low-density polyurethane foam

We describe several experiments performed at the LLNL Site 300 firing range and on the LLNL 1/3 scale gun to investigate the deceleration of small projectiles (l {approx} 3-5 [mm]) in low-density foam ({rho} {approx} 0.08-0.32 [g/cm{sup 3}]). The experiments at the firing range researched a passive velocity diagnostic based on Faraday's law of induction, while experiments on the 1/3 scale gun investigated the effects of varying projectile surface area, projectile shape, and foam density on the drag coefficient c{sub d}. Analysis shows that the velocity diagnostic has an uncertainty on the order of 1 percent for projectiles with velocity v {approx} 0.8-1.2 [km/s]. The 1/3 scale gun experiments, dubbed the Krispy Kreme series, included nine shots considering the combinations of 3 projectile surface areas with 3 target densities. The experiments used Tantalum square surface area block projectiles (with an initial velocity v{sub 0} {approx} 1.2 [km/s], a common thickness T = 2.67 [mm], and square side lengths of 3, 4, and 5 [mm]) decelerating in polyurethane foams (with densities {rho}{sub f} of 0.08, 0.16 and 0.32 [g/cm{sup 3}]). Standard fluid models of the Krispy Kreme experiments predict Reynolds numbers Re {approx} 10{sup 5} - 10{sup 6}, Mach numbers Ma …
Date: April 18, 2006
Creator: Adams, M L
Object Type: Report
System: The UNT Digital Library
Separation of Carbon Dioxide from Flue Gas Using Ion Pumping (open access)

Separation of Carbon Dioxide from Flue Gas Using Ion Pumping

We are developing a new way of separating carbon dioxide from flue gas based on ionic pumping of carbonate ions dissolved in water. Instead of relying on large temperature or pressure changes to remove carbon dioxide from solvent used to absorb it from flue gas, the ion pump increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, which can be removed from the downstream side of the ion pump as a nearly pure gas. This novel approach to increasing the concentration of the extracted gas permits new approaches to treating flue gas. The slightly basic water used as the extraction medium is impervious to trace acid gases that destroy existing solvents, and no pre-separation is necessary. The simple, robust nature of the process lends itself to small separation plants. Although the energy cost of the ion pump is significant, we anticipate that it will be compete favorably with the current 35% energy penalty of chemical stripping systems in use at power plants. There is the distinct possibility that this simple method could be significantly more efficient than existing processes.
Date: April 21, 2006
Creator: Aines, R.; Bourcier, W. L. & Johnson, M. R.
Object Type: Article
System: The UNT Digital Library
Project Work Plan 100-N Area Strontium-90 Treatability Demonstration Project: Phytoremediation Along the 100-N Columbia River Riparian Zone (open access)

Project Work Plan 100-N Area Strontium-90 Treatability Demonstration Project: Phytoremediation Along the 100-N Columbia River Riparian Zone

The 100-N Area Innovative Treatment and Remediation Demonstration (ITRD) identified phyto¬remediation as a potential technology both for the removal of 90Sr from the soil of the riparian zone and as a filter for groundwater along the Columbia River. Recent greenhouse and growth chamber studies have demonstrated the viability of phytoextraction to remove 90Sr from this area’s soil/water; in conjunction with monitored natural attenuation and an apatite barrier the process would make an effective treatment for remediation of the 100-N Area 90Sr plume. All activities associated with the 100-NR-1 and 100-NR-2 Operable Units of the Hanford 100-N Area have had, and continue to have, significant regulatory and stakeholder participation. Beginning in 1998 with the ITRD process, presentations to the ITRD TAG were heavily attended by EPA, Washington State Department of Ecology, and stakeholders. In addition, three workshops have been held to receive regulatory and stakeholder feedback on monitored natural attenuation, the apatite barrier, and phytoremediation; these were held in Richland in August 2003, December 2004, and August 2005. The apatite injection treatability test plan (DOE 2005) describes phytoremediation as a technology to be evaluated during the March 2008 evaluation milestone as described in the Tri-Party Agreement change request (M-16-06-01 Change Control …
Date: April 30, 2006
Creator: Ainsworth, Calvin C.
Object Type: Report
System: The UNT Digital Library
Modeling the Transport and Chemical Evolution of Onshore and Offshore Emissions and their Impact on Local and Regional Air Quality Using a Variable-Grid-Resolution Air Quality Model (open access)

Modeling the Transport and Chemical Evolution of Onshore and Offshore Emissions and their Impact on Local and Regional Air Quality Using a Variable-Grid-Resolution Air Quality Model

This Annual report summarizes the research performed from 17 April 2005 through 16 April 2006. Major portions of the research in several of the project's current eight tasks have been completed. We have successfully developed the meteorological inputs using the best possible modeling configurations, resulting in improved representation of atmospheric processes. The development of the variable-grid-resolution emissions model, SMOKE-VGR, is also completed. The development of the MAQSIP-VGR has been completed and a test run was performed to ensure the functionality of this air quality model. We have incorporated new emission data base to update the offshore emissions. However, we have faced some bottleneck problems in the testing the integrity of the new database. For this reason, we have asked for a no cost extension of this project to tackle these scientific problems. Thus, the project is on a one-year delay schedule. During the reporting period, we solved all problems related to the new emission database. We are ready to move to developing the final product, implementation and testing of the variable grid technology into the Community Multiscale Air Quality Model (CMAQ) to develop the CMAQ-VGR. During the upcoming months we will perform the first CMAQ-VGR simulations over the Houston-Galveston region …
Date: April 16, 2006
Creator: Alapaty, Kiran
Object Type: Report
System: The UNT Digital Library
Charm Spectroscopy at BaBar (open access)

Charm Spectroscopy at BaBar

In this note we present results on charmed hadron decays recently obtained from data recorded with the BABAR detector at the Stanford Linear Accelerator Center (SLAC) PEP-II B-Factory.
Date: April 21, 2006
Creator: Altenburg, D. & U., /Dortmund
Object Type: Article
System: The UNT Digital Library

Testing the Concept of Drift Shadow With X-Ray Absorption Imaging Experiments

None
Date: April 25, 2006
Creator: Altman, S.J.
Object Type: Presentation
System: The UNT Digital Library
Testing the COncept of Drift Shadow with X-Ray Absorption Imaging (open access)

Testing the COncept of Drift Shadow with X-Ray Absorption Imaging

X-ray absorption imaging experiments and measurements of inflow and outflow distribution provide quantitative and vistial evidence for capillary diversion around a drift and a drift-shadow effect. Test cells were constructed from volcanic tuff with either in-plane (one fracture parallel to the face of the test cell) or multi-fracture (with a grid of fractures perpendicular to the test cell) systems. Tracer solutions were dripped in the fractures at ports along the top of the test cell. Discharge along the bottom boundary and in the drift was monitored. Variables included flow rate and fracture aperture. X-ray absorption imaging allowed for visualization of flow paths through the system. Evidence for capillary diversion and drift shadow include: (1) very small (< 1 %,of inflow in most cases) measured discharge into the drift, (2) discharge less than expected under the drift and discharge greater than expected just beyond the drift, and (3) visualization of the tracer-solution flow path from above the drift, around the drift, and shedding beyond the drift. However, tracer was also observed in a natural fracture under the drift in one system. It is unclear whether these high concentrations are due to diversion around the drift and back under the drift or …
Date: April 24, 2006
Creator: Altman, S.J.; Forsberg, A.; Peplinski, W. & Ho, CK.
Object Type: Report
System: The UNT Digital Library
Persistent Patterns in Accretion Disks (open access)

Persistent Patterns in Accretion Disks

We present a set of new characteristic frequencies associated with accretion disks around compact objects. These frequencies arise from persistent rotating patterns in the disk that are finite in radial extent and driven purely by the gravity of the central body. Their existence depends on general relativistic corrections to orbital motion and, if observed, could be used to probe the strong gravity region around a black hole. We also discuss a possible connection to the puzzle of quasi-periodic oscillations.
Date: April 3, 2006
Creator: Amin, Mustafa A.; Frolov, Andrei V. & /KIPAC, Menlo Park
Object Type: Report
System: The UNT Digital Library
Plasma Biasing to Control the Growth Conditions of Diamond-Like Carbon (open access)

Plasma Biasing to Control the Growth Conditions of Diamond-Like Carbon

It is well known that the structure and properties ofdiamond-like carbon, and in particular the sp3/sp2 ratio, can becontrolled by the energy of the condensing carbon ions or atoms. In manypractical cases, the energy of ions arriving at the surface of thegrowing film is determined by the bias applied to the substrate. The biascauses a sheath to form between substrate and plasma in which thepotential difference between plasma potential and surface potentialdrops. In this contribution, we demonstrate that the same results can beobtained with grounded substrates by shifting the plasma potential. This"plasma biasing" (as opposed to "substrate biasing") is shown to workwell with pulsed cathodic carbon arcs, resulting in tetrahedral amorphouscarbon (ta-C) films that are comparable to the films obtained with theconventional substrate bias. To verify the plasma bias approach, ta-Cfilms were deposited by both conventional and plasma bias andcharacterized by transmission electron microscopy (TEM) and electronenergy loss spectrometry (EELS). Detailed data for comparison of thesefilms are provided.
Date: April 30, 2006
Creator: Anders, Andre; Pasaja, Nitisak; Lim, Sunnie H.N.; Petersen, TimC. & Keast, Vicki J.
Object Type: Article
System: The UNT Digital Library
Analysis of Residential System Strategies Targeting Least-Cost Solutions Leading to Net Zero Energy Homes: Preprint (open access)

Analysis of Residential System Strategies Targeting Least-Cost Solutions Leading to Net Zero Energy Homes: Preprint

The U. S. Department of Energy's Building America residential systems research project uses an analysis-based system research approach to identify research priorities, identify technology gaps and opportunities, establish a consistent basis to track research progress, and identify system solutions that are most likely to succeed as the initial targets for residential system research projects. This report describes the analysis approach used by the program to determine the most cost-effective pathways to achieve whole-house energy-savings goals. This report also provides an overview of design/technology strategies leading to net zero energy buildings as the basis for analysis of future residential system performance.
Date: April 1, 2006
Creator: Anderson, R.; Christensen, C. & Horowitz, S.
Object Type: Article
System: The UNT Digital Library
Oil Shale: History, Incentives, and Policy (open access)

Oil Shale: History, Incentives, and Policy

None
Date: April 13, 2006
Creator: Andrews, Anthony
Object Type: Report
System: The UNT Digital Library
3rd year final contractor report for: U.S. Department of Energy Stewardship Science Academic Alliances Program Project Title: Detailed Measurements of Rayleigh-Taylor Mixing at Large and Small Atwood Numbers (open access)

3rd year final contractor report for: U.S. Department of Energy Stewardship Science Academic Alliances Program Project Title: Detailed Measurements of Rayleigh-Taylor Mixing at Large and Small Atwood Numbers

This project had two major tasks: Task 1. The construction of a new air/helium facility to collect detailed measurements of Rayleigh-Taylor (RT) mixing at high Atwood number, and the distribution of these data to LLNL, LANL, and Alliance members for code validation and design purposes. Task 2. The collection of initial condition data from the new Air/Helium facility, for use with validation of RT simulation codes at LLNL and LANL. This report describes work done in the last twelve (12) months of the project, and also contains a summary of the complete work done over the three (3) life of the project. As of April 1, 2006, the air/helium facility (Task 1) is now complete and extensive testing and validation of diagnostics has been performed. Initial condition studies (Task 2) is also comp lete. Detailed experiments with air/helium with Atwood numbers up to 0.1 have been completed, and Atwood numbers of 0.25. Within the last three (3) months we have been able to successfully run the facility at Atwood numbers of 0.5. The progress matches the project plan, as does the budget. We have finished the initial condition studies using the water channel, and this work has been accepted for …
Date: April 14, 2006
Creator: Andrews, Malcolm J.
Object Type: Report
System: The UNT Digital Library
Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System (open access)

Assessing the Effects of Radiation Damage on Ni-base Alloys for the Prometheus Space Reactor System

Ni-base alloys were considered for the Prometheus space reactor pressure vessel with operational parameters of {approx}900 K for 15 years and fluences up to 160 x 10{sup 20} n/cm{sup 2} (E > 0.1 MeV). This paper reviews the effects of irradiation on the behavior of Ni-base alloys and shows that radiation-induced swelling and creep are minor considerations compared to significant embrittlement with neutron exposure. While the mechanism responsible for radiation-induced embrittlement is not fully understood, it is likely a combination of helium embrittlement and solute segregation that can be highly dependent on the alloy composition and exposure conditions. Transmutation calculations show that detrimental helium levels would be expected at the end of life for the inner safety rod vessel (thimble) and possibly the outer pressure vessel, primarily from high energy (E > 1 MeV) n,{alpha} reactions with {sup 58}Ni. Helium from {sup 10}B is significant only for the outer vessel due to the proximity of the outer vessel to the BeO control elements. Recommendations for further assessments of the material behavior and methods to minimize the effects of radiation damage through alloy design are provided.
Date: April 4, 2006
Creator: Angeliu, T.; Ward, J. & Witter, J.
Object Type: Report
System: The UNT Digital Library
Seismic Design and Retrofit of Equipment and Piping (open access)

Seismic Design and Retrofit of Equipment and Piping

None
Date: April 19, 2006
Creator: Antaki, George
Object Type: Article
System: The UNT Digital Library
Integrity of Pipes and Vessels Subject to Internal Explosions: an overview (open access)

Integrity of Pipes and Vessels Subject to Internal Explosions: an overview

None
Date: April 19, 2006
Creator: Antaki, George; McKeel, Charles & Pease, Derrick
Object Type: Article
System: The UNT Digital Library
Developments in Realistic Design for Aperiodic Mo/Si Multilayermirrors (open access)

Developments in Realistic Design for Aperiodic Mo/Si Multilayermirrors

Aperiodic multilayers have been designed for various applications, using numeric algorithms and analytical solutions, for many years with varying levels of success. This work developed a more realistic model for simulating aperiodic Mo/Si multilayers to be used in these algorithms by including the formation of MoSi{sub 2}. Using a genetic computer code we were able to optimize a 45{sup o} multilayer for a large bandpass reflection multilayer that gave good agreement with the model.
Date: April 5, 2006
Creator: Aquila, A. L.; Salmassi, F.; Dollar, F.; Liu, Y. & Gullikson, E. M.
Object Type: Article
System: The UNT Digital Library
European Union Enlargement (open access)

European Union Enlargement

None
Date: April 6, 2006
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library
The European Union in 2006 and Beyond (open access)

The European Union in 2006 and Beyond

The European Union (EU) experienced significant changes in 2004 as it enlarged from 15 to 25 members and continued work on a new constitutional treaty to institute internal reforms and further EU political integration. In 2005, the EU is expected to build on these efforts and seek to implement several recent foreign policy and defense initiatives. This report describes the current status of the EU’s “constitution,” EU enlargement, the EU’s evolving foreign and defense policies, and possible implications for U.S.-EU relations.
Date: April 6, 2006
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library
The European Union: Questions and Answers (open access)

The European Union: Questions and Answers

This report provides answers to key questions related to the European Union (EU). It describes the EU’s evolution, its governing institutions, trade policy, and efforts to forge common foreign and defense policies. The report also addresses the EU-U.S. and EU-NATO relationships.
Date: April 6, 2006
Creator: Archick, Kristin
Object Type: Report
System: The UNT Digital Library