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Search for the Rare Quark-annihilation Decays B->Ds(*)Phi (open access)

Search for the Rare Quark-annihilation Decays B->Ds(*)Phi

We report on searches for B{sup -} {yields} D{sub s}{sup -} {phi} and B{sup -} {yields} D*{sub s}{sup -} {phi}. In the context of the Standard Model, these decays are expected to be highly suppressed since they proceed through annihilation of the b and {bar u} quarks in the B{sup -} meson. Our results are based on 234 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at SLAC. We find no evidence for these decays, and we set Bayesian 90% confidence level upper limits on the branching fractions {Beta}(B{sup -} {yields} D{sub s}{sup -}{phi}) < 1.9 x 10{sup -6} and {Beta}(B{sup -} {yields} D*{sub s}{sup -} {phi}) < 1.2 x 10{sup -5}. These results are consistent with Standard Model expectations.
Date: December 19, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
System: The UNT Digital Library
Status of GLAST, the Gamma-ray Large-area Space Telescope (open access)

Status of GLAST, the Gamma-ray Large-area Space Telescope

GLAST is a satellite-based observatory consisting of the Large-Area Telescope (LAT), a modular 4 x 4-tower pair-conversion telescope with a field-of-view greater than 2 steradians, capable of measuring gamma-ray energies in the range 20 MeV to 300 GeV, and the GLAST Burst Monitor (GBM), a set of NaI and BGO detectors covering 8 steradians and sensitive to photons with energies between 10 keV and 25 MeV, allowing for correlative observations of transient events. The observatory is currently being constructed and is scheduled to be launched in August 2007.
Date: December 14, 2005
Creator: Rochester, L.
System: The UNT Digital Library
Investigating Uranium Isotopic Distributions in Environmental Samples Using AMS and MC-ICPMS (open access)

Investigating Uranium Isotopic Distributions in Environmental Samples Using AMS and MC-ICPMS

Major, minor, and trace uranium isotopes were measured at Lawrence Livermore National Laboratory in environmentally acquired samples using different instruments to span large variations in concentrations. Multi-collector inductively-coupled plasma mass spectrometry (MC-ICPMS) can be used to measure major and minor isotopes: {sup 238}U, {sup 235}U, {sup 234}U and {sup 236}U. Accelerator mass spectrometry (AMS) can be used to measure minor and trace isotopes: {sup 234}U, {sup 236}U, and {sup 233}U. The main limit of quantification for minor or trace uranium isotopes is the abundance sensitivity of the measurement technique; i.e., the ability to measure a minor or trace isotope of mass M in the presence of a major isotope at M{+-}1 mass units. The abundance sensitivity for {sup 236}U/{sup 235}U isotope ratio measurements using MC-ICPMS is around {approx}2x10{sup -6}. This compares with a {sup 236}U/{sup 235}U abundance sensitivity of {approx}1x10{sup -7} for the current AMS system, with the expectation of 2-3 orders of magnitude improvement in sensitivity with the addition of another high energy filter. Comparing {sup 236}U/{sup 234}U from MC-ICPMS and AMS produced agreement within {approx}10% for samples at {sup 236}U levels high enough to be measurable by both techniques.
Date: December 9, 2005
Creator: Buchholz, B. A.; Brown, T. A.; Hamilton, T. F.; Hutcheon, I. D.; Marchetti, A. A.; Martinelli, R. E. et al.
System: The UNT Digital Library
A Study of $e^+e^-\to p\bar{p}$ Using Initial StateRadiation with BaBar (open access)

A Study of $e^+e^-\to p\bar{p}$ Using Initial StateRadiation with BaBar

The e{sup +}e{sup -} {yields} p{bar p} cross-section is determined over a range of p{bar p} masses, from threshold to 4.5 GeV/c{sup 2}, by studying the e{sup +}e{sup -} {yields} p{bar p}{gamma} process. The data set corresponds to an integrated luminosity of 232 fb{sup -1}, collected with the BABAR detector at the PEP-II storage ring, at an e{sup +}e{sup -} center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, |G{sub E}/G{sub M}|, is measured for p{bar p} masses below 3 GeV/c{sup 2}; its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c{sup 2}. We also measure J/{psi} {yields} p{bar p} and {psi}(2S) {yields} p{bar p} branching fractions and set an upper limit on Y(4260) {yields} p{bar p} production and decay.
Date: December 13, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
System: The UNT Digital Library
Sub Angstrom imaging of dislocation core structures: How well areexperiments comparable with theory? (open access)

Sub Angstrom imaging of dislocation core structures: How well areexperiments comparable with theory?

During the past 50 years Transmission Electron Microscopy (TEM) has evolved from an imaging tool to a quantitative method that approaches the ultimate goal of understanding the atomic structure of materials atom by atom in three dimensions both experimentally and theoretically. Today's TEM abilities are tested in the special case of a Ga terminated 30 degree partial dislocation in GaAs:Be where it is shown that a combination of high-resolution phase contrast imaging, Scanning TEM, and local Electron Energy Loss Spectroscopy allows for a complete analysis of dislocation cores and associated stacking faults. We find that it is already possible to locate atom column positions with picometer precision in directly interpretable images of the projected crystal structure and that chemically different elements can already be identified together with their local electronic structure. In terms of theory, the experimental results can be quantitatively compared with ab initio electronic structure total energy calculations. By combining elasticity theory methods with atomic theory an equivalent crystal volume can be addressed. Therefore, it is already feasible to merge experiments and theory on a picometer length scale. While current experiments require the utilization of different, specialized instruments it is foreseeable that the rapid improvement of electron optical …
Date: December 16, 2005
Creator: Kisielowski, C.; Freitag, B.; Xu, X.; Beckman, S.P. & Chrzan, D.C.
System: The UNT Digital Library
Use of a Paraffin Based Grout to Stabilize Buried Beryllium and Other Wastes (open access)

Use of a Paraffin Based Grout to Stabilize Buried Beryllium and Other Wastes

The long term durability of WAXFIXi, a paraffin based grout, was evaluated for in situ grouting of activated beryllium wastes in the Subsurface Disposal Area (SDA), a radioactive landfill at the Radioactive Waste Management Complex, part of the Idaho National Laboratory (INL). The evaluation considered radiological and biological mechanisms that could degrade the grout using data from an extensive literature search and previous tests of in situ grouting at the INL. Conservative radioactive doses for WAXFIX were calculated from the "hottest" (i.e., highest-activity) Advanced Test Reactor beryllium block in the SDA.. These results indicate that WAXFIX would not experience extensive radiation damage for many hundreds of years. Calculation of radiation induced hydrogen generation in WAXFIX indicated that grout physical performance should not be reduced beyond the effects of radiation dose on the molecular structure. Degradation of a paraffin-based grout by microorganisms in the SDA is possible and perhaps likely, but the rate of degradation will be at a slower rate than found in the literature reviewed. The calculations showed the outer 0.46 m (18 in.) layer of each monolith, which represents the minimum expected distance to the beryllium block, was calculated to require 1,000 to 3,600 years to be consumed. …
Date: December 1, 2005
Creator: Matthern, Gretchen; Hanson, Duane; Yancey, Neal & Knudson, Darrell
System: The UNT Digital Library
Extrinsic Paramagnetic Meissner Effect in Multiphase Indium-Tin Alloys (open access)

Extrinsic Paramagnetic Meissner Effect in Multiphase Indium-Tin Alloys

A well-known effect in superconducting materials below their critical temperatures (T{sub c}) is the reduction to zero of their electrical resistivities. Concomitantly, the materials become perfect diamagnets for small fields. This effect, termed the Meissner Effect, allows for the direct measurement of the transition temperature (T{sub c}) by magnetic techniques such as the superconducting quantum interference device (SQUID). A Paramagnetic Meissner Effect (PME), i.e., the unexpected observation of positive magnetic moment in a superconductor below its critical temperature during field cooling (FC), was first reported in 1989 by Svedlindh et al. (1). The origin of PME in high T{sub c} superconductors has been discussed by numerous investigators as possibly resulting from {pi}-junctions, d-wave behavior, giant vortex states, flux compression, or weak links. In conventional superconductors like Nb, the PME was ascribed to the inhomogeneous nature of such samples, whereby their surface is sufficiently different from the interior and becomes superconducting at a higher temperature than the interior on cooling, thereby trapping the magnetic flux. There remains significant controversy regarding the fundamental origin of the PME. Here, we show that the PME in two-phase and three-phase In-Sn alloys is a property resulting from the morphological distribution of the multiple phases. We …
Date: December 2, 2005
Creator: Chu, S; Schwartz, A J; Massalski, T B & Laughlin, D E
System: The UNT Digital Library
Angularly Adaptive P1-Double P0 Flux-Limited Diffusion Solutions of Non-Equilibrium Grey Radiative Transfer Problems (open access)

Angularly Adaptive P1-Double P0 Flux-Limited Diffusion Solutions of Non-Equilibrium Grey Radiative Transfer Problems

The double spherical harmonics angular approximation in the lowest order, i.e. double P{sub 0} (DP{sub 0}), is developed for the solution of time-dependent non-equilibrium grey radiative transfer problems in planar geometry. Although the DP{sub 0} diffusion approximation is expected to be less accurate than the P{sub 1} diffusion approximation at and near thermodynamic equilibrium, the DP{sub 0} angular approximation can more accurately capture the complicated angular dependence near a non-equilibrium radiation wave front. In addition, the DP{sub 0} approximation should be more accurate in non-equilibrium optically thin regions where the positive and negative angular domains are largely decoupled. We develop an adaptive angular technique that locally uses either the DP{sub 0} or P{sub 1} flux-limited diffusion approximation depending on the degree to which the radiation and material fields are in thermodynamic equilibrium. Numerical results are presented for two test problems due to Su and Olson and to Ganapol and Pomraning for which semi-analytic transport solutions exist. These numerical results demonstrate that the adaptive P{sub 1}-DP{sub 0} diffusion approximation can yield improvements in accuracy over the standard P{sub 1} diffusion approximation, both without and with flux-limiting, for non-equilibrium grey radiative transfer.
Date: December 13, 2005
Creator: Brantley, P S
System: The UNT Digital Library
HDF5-FastQuery: Accelerating Complex Queries on HDF Datasets UsingFast Bitmap Indices (open access)

HDF5-FastQuery: Accelerating Complex Queries on HDF Datasets UsingFast Bitmap Indices

Large scale scientific data is often stored in scientific data formats such as FITS, netCDF and HDF. These storage formats are of particular interest to the scientific user community since they provide multi-dimensional storage and retrieval. However, one of the drawbacks of these storage formats is that they do not support semantic indexing which is important for interactive data analysis where scientists look for features of interests such as ''Find all supernova explosions where energy >105 and temperature >106''. In this paper we present a novel approach called HDF5-FastQuery to accelerate the data access of large HDF5 files by introducing multi-dimensional semantic indexing. Our implementation leverages an efficient indexing technology called ''bitmapindexing'' that has been widely used in the database community. Bitmapindices are especially well suited for interactive exploration of large-scale read-only data. Storing the bitmap indices into the HDF5 file has the following advantages: (a) Significant performance speedup of accessing subsets of multi-dimensional data and (b) portability of the indices across multiple computer platforms. We will present an API that simplifies the execution of queries on HDF5 files for general scientific applications and data analysis. The design is flexible enough to accommodate the use of arbitrary indexing technology for …
Date: December 7, 2005
Creator: Gosink, Luke; Shalf, John; Stockinger, Kurt; Wu, Kesheng & Bethel,Wes
System: The UNT Digital Library
Measurement of the inclusive jet cross section using the k(T) algorithm in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Measurement of the inclusive jet cross section using the k(T) algorithm in p anti-p collisions at s**(1/2) = 1.96-TeV

The authors report on a measurement of the inclusive jet production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using data collected with the upgraded Collider Detector at Fermilab in Run II (CDF II) corresponding to an integrated luminosity of 385 pb{sup -1}. Jets are reconstructed using the k{sub T} algorithm. The measurement is carried out for jets with rapidity 0.1 < |y{sup jet}| < 0.7 and transverse momentum in the range 54 < p{sub T}{sup jet} < 700 GeV/c. The measured cross section is in good agreement with next-to-leading order perturbative QCD predictions after the necessary non-perturbative parton-to-hadron corrections are included.
Date: December 1, 2005
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
System: The UNT Digital Library
Search for anomalous semileptonic decay of heavy flavor hadrons produced in association with a W boson at CDF II (open access)

Search for anomalous semileptonic decay of heavy flavor hadrons produced in association with a W boson at CDF II

None
Date: December 1, 2005
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
System: The UNT Digital Library
7Be(p,(gamma))8B S-factor from Ab Initio No-Core Shell Model Wave Functions (open access)

7Be(p,(gamma))8B S-factor from Ab Initio No-Core Shell Model Wave Functions

Nuclear structure of {sup 7}Be, {sup 8}B and {sup 7,8}Li is studied within the ab initio no-core shell model (NCSM). Starting from high-precision nucleon-nucleon (NN) interactions, wave functions of {sup 7}Be and {sup 8}B bound states are obtained in basis spaces up to 10 h bar{Omega} and used to calculate channel cluster form factors (overlap integrals) of the {sup 8}B ground state with {sup 7}Be+p. Due to the use of the harmonic oscillator (HO) basis, the overlap integrals have incorrect asymptotic properties. We fix this problem in two alternative ways. First, by a Woods-Saxon (WS) potential solution fit to the interior of the NCSM overlap integrals. Second, by a direct matching with the Whittaker function. The corrected overlap integrals are then used for the {sup 7}Be(p,{gamma}){sup 8}B S-factor calculation. We study the convergence of the S-factor with respect to the NCSM HO frequency and the model space size. Our S-factor results are in agreement with recent direct measurement data. We also test the spectroscopic factors and the corrected overlap integrals from the NCSM in describing the momentum distributions in knockout reactions with {sup 8}B projectiles. A good agreement with the available experimental data is also found, attesting the overall consistency …
Date: December 2, 2005
Creator: Navratil, P; Bertulani, C A & Caurier, E
System: The UNT Digital Library
A Visualization Methodology for Characterization of Network Scans (open access)

A Visualization Methodology for Characterization of Network Scans

Many methods have been developed for monitoring network traffic, both using visualization and statistics. Most of these methods focus on the detection of suspicious or malicious activities. But what they often fail to do refine and exercise measures that contribute to the characterization of such activities and their sources, once they are detected. In particular, many tools exist that detect network scans or visualize them at a high level, but not very many tools exist that are capable of categorizing and analyzing network scans. This paper presents a means of facilitating the process of characterization by using visualization and statistics techniques to analyze the patterns found in the timing of network scans through a method of continuous improvement in measures that serve to separate the components of interest in the characterization so the user can control separately for the effects of attack tool employed, performance characteristics of the attack platform, and the effects of network routing in the arrival patterns of hostile probes. The end result is a system that allows large numbers of network scans to be rapidly compared and subsequently identified.
Date: December 15, 2005
Creator: Muelder, C W; Ma, K & Bartoletti, A
System: The UNT Digital Library
A Flexure-Based Tool Holder for Sub-(micro)m Positioning of a Single Point Cutting Tool on a Four-axis Lathe (open access)

A Flexure-Based Tool Holder for Sub-(micro)m Positioning of a Single Point Cutting Tool on a Four-axis Lathe

A tool holder was designed to facilitate the machining of precision meso-scale components with complex three-dimensional shapes with sub-{micro}m accuracy on a four-axis lathe. A four-axis lathe incorporates a rotary table that allows the cutting tool to swivel with respect to the workpiece to enable the machining of complex workpiece forms, and accurately machining complex meso-scale parts often requires that the cutting tool be aligned precisely along the axis of rotation of the rotary table. The tool holder designed in this study has greatly simplified the process of setting the tool in the correct location with sub-{micro}m precision. The tool holder adjusts the tool position using flexures that were designed using finite element analyses. Two flexures adjust the lateral position of the tool to align the center of the nose of the tool with the axis of rotation of the B-axis, and another flexure adjusts the height of the tool. The flexures are driven by manual micrometer adjusters, each of which provides a minimum increment of motion of 20 nm. This tool holder has simplified the process of setting a tool with sub-{micro}m accuracy, and it has significantly reduced the time required to set a tool.
Date: December 5, 2005
Creator: Bono, M J & Hibbard, R L
System: The UNT Digital Library
Search for second-generation scalar leptoquarks in p anti-p collisions at s**(1/2) = 1.96-TeV (open access)

Search for second-generation scalar leptoquarks in p anti-p collisions at s**(1/2) = 1.96-TeV

None
Date: December 1, 2005
Creator: Abulencia, A.; Acosta, D.; Adelman, Jahred A.; Affolder, Anthony A.; Akimoto, T.; Albrow, M.G. et al.
System: The UNT Digital Library
Relativistic Bound States (open access)

Relativistic Bound States

The Hamiltonian for Dirac's second-order equation depends nonlinearly on the potential V and the energy E. For this reason the magnetic contribution to the Hamiltonian for s-waves, which has a short range, is attractive for a repulsive Coulomb potential (V > 0) and repulsive for an attractive Coulomb potential (V < 0). Previous studies are confined to the latter case, where strong net attraction near a high-Z nucleus accelerates electrons to velocities close to the speed of light. The Hamiltonian is linear in the product EV/mc{sup 2}. Usually solutions are found in the regime E = mc{sup 2} + {var_epsilon}, where except for high Z, |{var_epsilon}| << mc{sup 2}. Here they show that for V > 0 the attractive magnetic term and the repulsive linear term combine to support a bound state at E = 0.5 mc{sup 2} corresponding to a binding energy E{sub b} = -{var_epsilon} = 0.5 mc{sup 2}.
Date: December 12, 2005
Creator: Ritchie, A. B.
System: The UNT Digital Library
EXTENDING PRESSURE RELIEF VALVE INSPECTION INTERVALS BY USING STATISTICAL ANALYSIS OF PROOF TEST DATA (open access)

EXTENDING PRESSURE RELIEF VALVE INSPECTION INTERVALS BY USING STATISTICAL ANALYSIS OF PROOF TEST DATA

None
Date: December 2, 2005
Creator: GROSS, ROBERT
System: The UNT Digital Library
Designing a multi-petabyte database for LSST (open access)

Designing a multi-petabyte database for LSST

The 3.2 giga-pixel LSST camera will produce over half a petabyte of raw images every month. This data needs to be reduced in under a minute to produce real-time transient alerts, and then cataloged and indexed to allow efficient access and simplify further analysis. The indexed catalogs alone are expected to grow at a speed of about 600 terabytes per year. The sheer volume of data, the real-time transient alerting requirements of the LSST, and its spatio-temporal aspects require cutting-edge techniques to build an efficient data access system at reasonable cost. As currently envisioned, the system will rely on a database for catalogs and metadata. Several database systems are being evaluated to understand how they will scale and perform at these data volumes in anticipated LSST access patterns. This paper describes the LSST requirements, the challenges they impose, the data access philosophy, and the database architecture that is expected to be adopted in order to meet the data challenges.
Date: December 21, 2005
Creator: Becla, J & Hanushevsky, A
System: The UNT Digital Library
Multiconfiguration Dirac-Fock Wavelengths and Transition Rates in the X-Ray Spectra of Highly Charged Ga-like Ions from Yb39+ to U61+ (open access)

Multiconfiguration Dirac-Fock Wavelengths and Transition Rates in the X-Ray Spectra of Highly Charged Ga-like Ions from Yb39+ to U61+

None
Date: December 20, 2005
Creator: Quinet, P.; Biemont, E.; Palmeri, P. & Trabert, E.
System: The UNT Digital Library
Environmental Whole-Genome Amplification to Access Microbial Diversity in Contaminated Sediments (open access)

Environmental Whole-Genome Amplification to Access Microbial Diversity in Contaminated Sediments

Low-biomass samples from nitrate and heavy metal contaminated soils yield DNA amounts that have limited use for direct, native analysis and screening. Multiple displacement amplification (MDA) using ?29 DNA polymerase was used to amplify whole genomes from environmental, contaminated, subsurface sediments. By first amplifying the genomic DNA (gDNA), biodiversity analysis and gDNA library construction of microbes found in contaminated soils were made possible. The MDA method was validated by analyzing amplified genome coverage from approximately five Escherichia coli cells, resulting in 99.2 percent genome coverage. The method was further validated by confirming overall representative species coverage and also an amplification bias when amplifying from a mix of eight known bacterial strains. We extracted DNA from samples with extremely low cell densities from a U.S. Department of Energy contaminated site. After amplification, small subunit rRNA analysis revealed relatively even distribution of species across several major phyla. Clone libraries were constructed from the amplified gDNA, and a small subset of clones was used for shotgun sequencing. BLAST analysis of the library clone sequences showed that 64.9 percent of the sequences had significant similarities to known proteins, and ''clusters of orthologous groups'' (COG) analysis revealed that more than half of the sequences from …
Date: December 10, 2005
Creator: Abulencia, C. B.; Wyborski, D. L.; Garcia, J.; Podar, M.; Chen, W.; Chang, S. H. et al.
System: The UNT Digital Library
QUANTITATIVE ANALYSES OF THE SEVERITY OF ATTACK ON CREVICE CORROSION SURFACES (open access)

QUANTITATIVE ANALYSES OF THE SEVERITY OF ATTACK ON CREVICE CORROSION SURFACES

None
Date: December 19, 2005
Creator: /a, n
System: The UNT Digital Library
Dark matter and gamma-rays from Draco: MAGIC, GLAST and CACTUS (open access)

Dark matter and gamma-rays from Draco: MAGIC, GLAST and CACTUS

The dwarf spheroidal galaxy Draco has long been considered likely to be one of the brightest point sources of gamma-rays generated through dark matter annihilations. Recent studies of this object have found that it remains largely intact from tidal striping, and may be more massive than previously thought. In this article, we revisit Draco as a source of dark matter annihilation radiation, with these new observational constraints in mind. We discuss the prospects for the experiments MAGIC and GLAST to detect dark matter in Draco, as well as constraints from the observations of EGRET. We also discuss the possibility that the CACTUS experiment has already detected gamma-rays from Draco. We find that it is difficult to generate the flux reported by CACTUS without resorting to non-thermally produced WIMPs and/or a density spike in Draco's dark matter distribution due to the presence of an intermediate mass black hole. We also find that for most annihilation modes, a positive detection of Draco by CACTUS would be inconsistent with the lack of events seen by EGRET.
Date: December 1, 2005
Creator: Bergstrom, Lars; U., /Stockholm; Hooper, Dan & /Fermilab
System: The UNT Digital Library
The optical properties of a polished uranium surface and its epitaxial oxide, and the rate of oxide growth determined by spectrophotometry (open access)

The optical properties of a polished uranium surface and its epitaxial oxide, and the rate of oxide growth determined by spectrophotometry

None
Date: December 12, 2005
Creator: Siekhaus, W J & Nelson, A J
System: The UNT Digital Library
Surface chemistry controls crystallinity of ZnSnanoparticles (open access)

Surface chemistry controls crystallinity of ZnSnanoparticles

Combined small-angle and high energy wide-angle x-ray scattering measurements of nanoparticle size and structure permit interior strain and disorder to be directly observed in the real-space pair distribution function (PDF). PDF analysis showed that samples of ZnS nanoparticle with similar mean diameters (3.2-3.6 nm) but synthesized and treated differently possess a dramatic range of interior disorder. We used Fourier transform infra-red spectroscopy to detect the surface species and the nature of surface chemical interactions. Our results suggest that there is a direct correlation between the strength of surface-ligand interactions and interior crystallinity.
Date: December 20, 2005
Creator: Gilbert, Benjamin; Huang, Feng; Lin, Zhang; Goodell, Carmen; Zhang, Hengzhong & F., Banfield Jillian
System: The UNT Digital Library