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
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
COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN (open access)

COST-EFFECTIVE METHOD FOR PRODUCING SELF SUPPORTED PALLADIUM ALLOY MEMBRANES FOR USE IN EFFICIENT PRODUCTION OF COAL DERIVED HYDROGEN

None
Date: April 1, 2006
Creator: Arps, J.
Object Type: Report
System: The UNT Digital Library
Thermal aging of the polyurethane foam for the H1259 storage container. (open access)

Thermal aging of the polyurethane foam for the H1259 storage container.

None
Date: April 1, 2006
Creator: Assink, Roger Alan; Elliott, Julie M. & Celina, Mathias Christopher
Object Type: Report
System: The UNT Digital Library
Actinide Targets for Neutron Cross Section Measurements (C) (open access)

Actinide Targets for Neutron Cross Section Measurements (C)

The Advanced Fuel Cycle Initiative (AFCI) and the Generation IV Reactor Initiative have demonstrated a lack of detailed neutron cross-sections for certain "minor" actinides, those other than the most common (235U, 238U, and 239Pu). For some closed-fuel-cycle reactor designs more than 50% of reactivity will, at some point, be derived from “minor” actinides that currently have poorly known (n,g) and (n,f) cross sections. A program of measurements under AFCI has begun to correct this. One of the initial hurdles has been to produce well-characterized, highly isotopically enriched, and chemically pure actinide targets on thin backings. Using a combination of resurrected techniques and new developments, we have made a series of targets including highly enriched 240Pu, and 242Pu. Thus far, we have electrodeposited these actinide targets. In the future, we plan to study reductive distillation to achieve homogeneous, adherent targets on thin metal foils and polymer backings. As we move forward, separated isotopes become scarcer, and safety concerns become greater. The chemical purification and electodeposition techniques will be described.
Date: April 1, 2006
Creator: Baker, J. D. & McGrath, C. A.
Object Type: Article
System: The UNT Digital Library
Transverse coherent instability of a bunch in a rectangular potential well (open access)

Transverse coherent instability of a bunch in a rectangular potential well

Theory of transverse instability of a bunch in a rectangular potential well is developed. Series of equations adequately describing the instability is derived and solved both analytically and numerically. Dependence of the instability increment and threshold on bunch factor is investigated for various beam coupling impedances. The theory is applied to the Fermilab Recycler Ring.
Date: April 1, 2006
Creator: Balbekov, V.
Object Type: Article
System: The UNT Digital Library
Neutrino Coannihilation on Dark-Matter Relics? (open access)

Neutrino Coannihilation on Dark-Matter Relics?

High-energy neutrinos may resonate with relic background neutralinos to form short-lived sneutrinos. In some circumstances, the decay chain that leads back to the lightest supersymmetric particle would yield few-GeV gamma rays or charged-particle signals. Although resonant coannihilation would occur at an appreciable rate in our galaxy, the signal in any foreseeable detector is unobservably small.
Date: April 1, 2006
Creator: Barenboim, Gabriela; Mena Requejo, Olga & Quigg, Chris
Object Type: Article
System: The UNT Digital Library
Influence of soil physicochemical properties on hydrology and restoration response in Carolina Bay wetlands. (open access)

Influence of soil physicochemical properties on hydrology and restoration response in Carolina Bay wetlands.

Carolina Bays are shallow depression wetlands found in the southeast US that have been severely altered by human activity. The need to restore these complex and diverse systems is well established, but our understanding of basic wetland hydrological processes is limited, hence our ability to predict the need for and/or assess the effectiveness of bay restorations is hindered. Differing physicochemical properties of soils within bay interiors may control bay hydrology. However, previous efforts to establish relationships between soil characteristics and bay hydrology have been inconclusive and the question still remains as to why some bays are ponded throughout the year while others, within a similar landscape unit, are predominantly dry. An assessment of soil and hydrologic characteristics was initiated in restored and unrestored control bays to determine if a relationship exists. Soil morphology was described and permanent monitoring wells were installed at each site. Soil samples were collected by horizon to a depth of 2 meters at the topographic center of each site, and then analyzed. After three years, multiple regression analysis (stepwise backward and forward) was used to establish relationships between the soil physicochemical characteristics and bay hydroperiod in the undisturbed sites. Results from surface soils indicated that exchangeable …
Date: April 1, 2006
Creator: Barton, C. D.; Andrews, D. M. & Kolka, R. K.
Object Type: Article
System: The UNT Digital Library
Utility-Marketing Partnerships: An Effective Strategy for Marketing Green Power? (open access)

Utility-Marketing Partnerships: An Effective Strategy for Marketing Green Power?

This paper explores whether partnerships between utilities and independent marketers are an effective strategy for marketing green power. We present case studies of voluntary and mandatory partnerships covering green power program design and implementation in both regulated and restructured electricity markets. We also include perspectives (based on interviews) from utilities, marketers, and regulators involved in developing and implementing these partnerships. From these case studies and interviews, we describe lessons learned about developing effective partnerships, including such issues as respective roles in marketing and administration, product branding, and contract and incentive structures. Based on experience to date, strategic partnerships between utilities and marketers can be an effective approach to marketing green power. Partnerships leverage the sales and resource procurement experience of marketers and the utility?s reputation and access to customers. Further, partnerships can create greater incentives for success because marketers have a vested financial interest in maximizing customer participation and green power sales.
Date: April 1, 2006
Creator: Bird, L. A. & Brown, E. S.
Object Type: Report
System: The UNT Digital Library
Concentrating Solar Deployment System (CSDS) -A New Model for Estimating U.S. Concentrating Solar Power (CSP) Market Potential (open access)

Concentrating Solar Deployment System (CSDS) -A New Model for Estimating U.S. Concentrating Solar Power (CSP) Market Potential

This paper presents the Concentrating Solar Deployment System Model (CSDS). CSDS is a multiregional, multitime-period, Geographic Information System (GIS), and linear programming model of capacity expansion in the electric sector of the United States. CSDS is designed to address the principal market and policy issues related to the penetration of concentrating solar power (CSP) electric-sector technologies. This paper discusses the current structure, capabilities, and assumptions of the model. Additionally, results are presented for the impact of continued research and development (R&D) spending, an extension to the investment tax credit (ITC), and use of a production tax credit (PTC). CSDS is an extension of the Wind Deployment System (WinDS) model created at the National Renewable Energy Laboratory (NREL). While WinDS examines issues related to wind, CSDS is an extension to analyze similar issues for CSP applications. Specifically, a detailed representation of parabolic trough systems with thermal storage has been developed within the existing structure.
Date: April 1, 2006
Creator: Blair, N.; Mehos, M.; Short, W. & Heimiller, D.
Object Type: Article
System: The UNT Digital Library
Using Unmanned Aerial Vehicles to Assess Vegetative Cover and Identify Biotic Resources in Sagebrush Steppe Ecosystems: Preliminary Evaluation (open access)

Using Unmanned Aerial Vehicles to Assess Vegetative Cover and Identify Biotic Resources in Sagebrush Steppe Ecosystems: Preliminary Evaluation

The Idaho National Laboratory (INL), in conjunction with the University of Idaho, is evaluating novel approaches for using unmanned aerial vehicles (UAVs) as a quicker and safer method for monitoring biotic resources. Evaluating vegetative cover is an important factor in understanding the sustainability of many ecosystems. In assessing vegetative cover, methods that improve accuracy and cost efficiency could revolutionize how biotic resources are monitored on western federal lands. Sagebrush steppe ecosystems provide important habitat for a variety of species, some of which are important indicator species (e.g., sage grouse). Improved methods are needed to support monitoring these habitats because there are not enough resource specialists or funds available for comprehensive ground evaluation of these ecosystems. In this project, two types of UAV platforms (fixed wing and helicopter) were used to collect still-frame imagery to assess cover in sagebrush steppe ecosystems. This paper discusses the process for collecting and analyzing imagery from the UAVs to (1) estimate total percent cover, (2) estimate percent cover for six different types of vegetation, and (3) locate sage grouse based on representative decoys. The field plots were located on the INL site west of Idaho Falls, Idaho, in areas with varying amounts and types of …
Date: April 1, 2006
Creator: Breckenridge, Robert P.
Object Type: Article
System: The UNT Digital Library
Hemispheric ultra-wideband antenna. (open access)

Hemispheric ultra-wideband antenna.

This report begins with a review of reduced size ultra-wideband (UWB) antennas and the peculiar problems that arise when building a UWB antenna. It then gives a description of a new type of UWB antenna that resolves these problems. This antenna, dubbed the hemispheric conical antenna, is similar to a conventional conical antenna in that it uses the same inverted conical conductor over a ground plane, but it also uses a hemispheric dielectric fill in between the conductive cone and the ground plane. The dielectric material creates a fundamentally new antenna which is reduced in size and much more rugged than a standard UWB conical antenna. The creation of finite-difference time domain (FDTD) software tools in spherical coordinates, as described in SAND2004-6577, enabled this technological advance.
Date: April 1, 2006
Creator: Brocato, Robert Wesley
Object Type: Report
System: The UNT Digital Library
Two-Beam Instability in Electron Cooling (open access)

Two-Beam Instability in Electron Cooling

The drift motion of cooling electrons makes them able to respond to transverse perturbations of a cooled ion beam. This response may lead to dipole or quadrupole transverse instabilities at specific longitudinal wave numbers. While the dipole instabilities can be suppressed by a combination of the Landau damping, machine impedance, and the active damper, the quadrupole and higher order modes can lead to either emittance growth, or a lifetime degradation, or both. The growth rates of these instabilities are strongly determined by the machine x-y coupling. Thus, tuning out of the coupling resonance and/or reduction of the machine coupling can be an efficient remedy for these instabilities.
Date: April 1, 2006
Creator: Burov, Alexey V.
Object Type: Article
System: The UNT Digital Library
King County Metro Transit Hybrid Articulated Transit Buses: Interim Evaluation Results (open access)

King County Metro Transit Hybrid Articulated Transit Buses: Interim Evaluation Results

Interim technical report compares and evaluates new diesel and diesel hybrid-electric articulated buses operated as part of the King County Metro Transit (KC Metro) fleet in Seattle, Washington.
Date: April 1, 2006
Creator: Chandler, K. & Walkowicz, K.
Object Type: Report
System: The UNT Digital Library
Washington Metropolitan Area Transit Authority: Compressed Natural Gas Transit Bus Evaluation (open access)

Washington Metropolitan Area Transit Authority: Compressed Natural Gas Transit Bus Evaluation

Evaluates compressed natural gas (CNG) powered transit buses at Washington Metropolitan Area Transit Authority (WMATA), providing a comparison between them and standard diesel transit buses.
Date: April 1, 2006
Creator: Chandler, K.; Eberts, E. & Melendez, M.
Object Type: Report
System: The UNT Digital Library
Higgs triplets and limits from precision measurements (open access)

Higgs triplets and limits from precision measurements

In this letter, they present the results on a global fit to precision electroweak data in a Higgs triplet model. In models with a triplet Higgs boson, a consistent renormalization scheme differs from that of the Standard Model and the global fit shows that a light Higgs boson with mass of 100-200 GeV is preferred. Triplet Higgs bosons arise in many extensions of the Standard Model, including the left-right model and the Little Higgs models. The result demonstrates the importance of the scalar loops when there is a large mass splitting between the heavy scalars. It also indicates the significance of the global fit.
Date: April 1, 2006
Creator: Chen, Mu-Chun; Dawson, Sally & Krupovnickas, Tadas
Object Type: Article
System: The UNT Digital Library
Electroweak Production of the Top Quark in the Run II of the D0 Experiment (open access)

Electroweak Production of the Top Quark in the Run II of the D0 Experiment

The work exposed in this thesis deals with the search for electroweak production of top quark (single top) in proton-antiproton collisions at {radical}s = 1.96 TeV. This production mode has not been observed yet. Analyzed data have been collected during the Run II of the D0 experiment at the Fermilab Tevatron collider. These data correspond to an integrated luminosity of 370 pb{sup -1}. In the Standard Model, the decay of a top quark always produce a high momentum bottom quark. Therefore bottom quark jets identification plays a major role in this analysis. The large lifetime of b hadrons and the subsequent large impact parameters relative to the interaction vertex of charged particle tracks are used to tag bottom quark jets. Impact parameters of tracks attached to a jet are converted into the probability for the jet to originate from the primary vertex. This algorithm has a 45% tagging efficiency for a 0.5% mistag rate. Two processes (s and t channels) dominate single top production with slightly different final states. The searched signature consists in 2 to 4 jets with at least one bottom quark jet, one charged lepton (electron or muon) and missing energy accounting for a neutrino. This final …
Date: April 1, 2006
Creator: Clement, Benoit & /Strasbourg, IReS
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Aluminum equation of state validation and verification for the ALEGRA HEDP simulation code. (open access)

Aluminum equation of state validation and verification for the ALEGRA HEDP simulation code.

None
Date: April 1, 2006
Creator: Cochrane, Kyle Robert; Knudson, Marcus D.; Haill, Thomas A.; Desjarlais, Michael Paul; Lawrence, Jeffrey & Dunham, Gregory Sham
Object Type: Report
System: The UNT Digital Library
Multiple factors affect pest and pathogen damage on 31 Populus clones in South Carolina. (open access)

Multiple factors affect pest and pathogen damage on 31 Populus clones in South Carolina.

Abstract Populus species and hybrids have many practical applications, but there is a paucity of data regarding selections that perform well in the southeastern US. We compared pest susceptibility of 31 Populus clones over 3 years in South Carolina, USA. Cuttings were planted in spring 2001 on two study sites. Clones planted in the bottomland site received granular fertilizer yearly and irrigation the first two years only, while those on the sandy, upland site received irrigation and fertilization throughout each growing season. Foliar damage by the cottonwood leaf beetle (Chrysomela scripta), cottonwood leafcurl mite (Tetra lobulifera), and poplar leaf rust (Melampsora medusae) was visually monitored several times each growing season. Damage ratings differed significantly among clones, and clonal rankings changed from year to year. Irrigation increased C. scripta and M. medusae damage, but had no effect on T. lobulifera damage. Certain clones received greater pest damage at a particular study site. Temporal damage patterns were evident among individual clones and on each site. At the upland site, OP367 and 7300502 were highly resistant to all three pests; I45/51 was highly resistant to C. scripta and M. medusae; NM6 and 15–29 were highly resistant to M. medusae; and 7302801 was highly …
Date: April 1, 2006
Creator: Coyle, David R.; Coleman, Mark D.; Durant, Jaclin A. & Newman, Lee A.
Object Type: Article
System: The UNT Digital Library
Survival and growth of 31 Populus clones in South Carolina. (open access)

Survival and growth of 31 Populus clones in South Carolina.

Abstract Populus species and hybrids have many practical applications, but clonal performance is relatively undocumented in the southeastern United States outside of the Mississippi River alluvial floodplain. In spring 2001, 31 Populus clones were planted on two sites in South Carolina, USA. The sandy, upland site received irrigation and fertilization throughout the growing season, while the bottomland site received granular fertilizer yearly and irrigation in the first two years only. Over three growing seasons, tree survival and growth differed significantly among clones at both sites. Hybrid clones I45/51, Eridano, and NM6 had very high survival at both sites, while pure eastern cottonwood (P. deltoides) clones consistently had the lowest survival. Nearly all mortality occurred during the first year. The P. deltoides clone WV416 grew well at both sites, P. deltoides clones S13C20 and Kentucky 8 grew well at the bottomland site, and hybrids 184-411 and 52-225 grew well at the upland site. Based on both survival and growth, clones 311-93, S7C15, 184-411, and WV416 may warrant additional testing in the upper coastal plain region of the southeastern US. Kentucky 8 and S13C20 had excellent growth rates, but initial survival was low. However, this was likely due to planting stock quality. …
Date: April 1, 2006
Creator: Coyle, David R.; Coleman, Mark D.; Durant, Jaclin A. & Newman, Lee A.
Object Type: Article
System: The UNT Digital Library