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On a theory of neutrino oscillations with entanglement (open access)

On a theory of neutrino oscillations with entanglement

We show that the standard expression for the neutrino oscillation length can be confirmed even in theoretical approaches that take into account entanglement between the neutrino and its interaction partners. We show this in particular for the formalism developed in arXiv:1004.1847. Finally, we shed some light on the question why plane-wave approaches to the neutrino oscillation problem can yield the correct result for the oscillation length even though they do not explicitly account for the localization of the neutrino source and the detector.
Date: June 1, 2010
Creator: Kayser, Boris; Kopp, Joachim; Roberston, R. G. Hamish & Vogel, Petr
System: The UNT Digital Library
Kinetics of Fe(II)-catalyzed transformation of 6-line ferrihydrite under anaerobic flow conditions (open access)

Kinetics of Fe(II)-catalyzed transformation of 6-line ferrihydrite under anaerobic flow conditions

The readsorption of ferrous ions produced by the abiotic and microbially-mediated reductive dissolution of iron oxy-hydroxides drives a series of transformations of the host minerals. To further understand the mechanisms by which these transformations occur and their kinetics within a microporous flow environment, flow-through experiments were conducted in which capillary tubes packed with ferrihydrite-coated glass spheres were injected with inorganic Fe(II) solutions under circumneutral pH conditions at 25 C. Synchrotron X-ray diffraction was used to identify the secondary phase(s) formed and to provide data for quantitative kinetic analysis. At concentrations at and above 1.8 mM Fe(II) in the injection solution, magnetite was the only secondary phase formed (no intermediates were detected), with complete transformation following a nonlinear rate law requiring 28 hours and 150 hours of reaction at 18 and 1.8 mM Fe(II), respectively. However, when the injection solution consisted of 0.36 mM Fe(II), goethite was the predominant reaction product and formed much more slowly according to a linear rate law, while only minor magnetite was formed. When the rates are normalized based on the time to react half of the ferrihydrite on a reduced time plot, it is apparent that the 1.8 mM and 18 mM input Fe(II) experiments …
Date: April 1, 2010
Creator: Yang, L.; Steefel, C. I.; Marcus, M. A. & Bargar, J. R.
System: The UNT Digital Library
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter (open access)

Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter

Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuzmin energy threshold, 6 x 10{sup 19} eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1{sup o} from the position of an active galactic nucleus within 75 Mpc (using the Veron-Cetty and Veron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38{sub -6}{sup +7})%, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of (69{sub -13}{sup +11})%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function …
Date: June 1, 2010
Creator: Abreu, P.; /Lisbon, IST; Aglietta, M.; /Turin U. /INFN, Turin; Ahn, E.J.; /Fermilab et al.
System: The UNT Digital Library
Development of Hollow Electron Beams for Proton and Ion Collimation (open access)

Development of Hollow Electron Beams for Proton and Ion Collimation

Magnetically confined hollow electron beams for controlled halo removal in high-energy colliders such as the Tevatron or the LHC may extend traditional collimation systems beyond the intensity limits imposed by tolerable material damage. They may also improve collimation performance by suppressing loss spikes due to beam jitter and by increasing capture efficiency. A hollow electron gun was designed and built. Its performance and stability were measured at the Fermilab test stand. The gun will be installed in one of the existing Tevatron electron lenses for preliminary tests of the hollow-beam collimator concept, addressing critical issues such as alignment and instabilities of the overlapping proton and electron beams.
Date: June 1, 2010
Creator: Stancari, G.; Drozhdin, A.I.; Kuznetsov, G.; Shiltsev, V.; Still, D.A.; Valishev, A. et al.
System: The UNT Digital Library
Measurement of the $WW+WZ$ Production Cross Section Using a Matrix Element Technique in Lepton + Jets Events (open access)

Measurement of the $WW+WZ$ Production Cross Section Using a Matrix Element Technique in Lepton + Jets Events

We present a measurement of the WW + WZ production cross section observed in a final state consisting of an identified electron or muon, two jets, and missing transverse energy. The measurement is carried out in a data sample corresponding to up to 4.6 fb{sup -1} of integrated luminosity at {radical}s = 1.96 TeV collected by the CDF II detector. Matrix element calculations are used to separate the diboson signal from the large backgrounds. The WW + WZ cross section is measured to be 17.4 {+-} 3.3 pb, in agreement with standard model predictions. A fit to the dijet invariant mass spectrum yields a compatible cross section measurement.
Date: August 1, 2010
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
System: The UNT Digital Library
Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon (open access)

Observation in the MINOS far detector of the shadowing of cosmic rays by the sun and moon

The shadowing of cosmic ray primaries by the the moon and sun was observed by the MINOS far detector at a depth of 2070 mwe using 83.54 million cosmic ray muons accumulated over 1857.91 live-days. The shadow of the moon was detected at the 5.6 {sigma} level and the shadow of the sun at the 3.8 {sigma} level using a log-likelihood search in celestial coordinates. The moon shadow was used to quantify the absolute astrophysical pointing of the detector to be 0.17 {+-} 0.12{sup o}. Hints of Interplanetary Magnetic Field effects were observed in both the sun and moon shadow.
Date: August 1, 2010
Creator: Adamson, P.; Andreopoulos, C.; Ayres, D. S.; Backhouse, C.; Barr, G.; Barrett, W. L. et al.
System: The UNT Digital Library
Fabrication and Comparison of Fuels for Advanced Gas Reactor Irradiation Tests (open access)

Fabrication and Comparison of Fuels for Advanced Gas Reactor Irradiation Tests

As part of the program to demonstrate TRISO-coated fuel for the Next Generation Nuclear Plant, a series of irradiation tests of Advanced Gas Reactor (AGR) fuel are being performed in the Advanced Test Reactor (ATR) at the Idaho National Laboratory. In the first test, called “AGR-1,” graphite compacts containing approximately 300,000 coated particles were irradiated from December 2006 until November 2009. Development of AGR-1 fuel sought to replicate the properties of German TRISO-coated particles. No particle failures were seen in the nearly 3-year irradiation to a burn up of 19%. The AGR-1 particles were coated in a two-inch diameter coater. Following fabrication of AGR-1 fuel, process improvements and changes were made in each of the fabrication processes. Changes in the kernel fabrication process included replacing the carbon black powder feed with a surface-modified carbon slurry and shortening the sintering schedule. AGR-2 TRISO particles were produced in a six-inch diameter coater using a change size about twenty-one times that of the two-inch diameter coater used to coat AGR-1 particles. Changes were also made in the compacting process, including increasing the temperature and pressure of pressing and using a different type of press. Irradiation of AGR-2 fuel began in late spring 2010. …
Date: October 1, 2010
Creator: Phillips, Jeffrey; Barnes, Charles & Hunn, John
System: The UNT Digital Library
Soft QCD at Tevatron (open access)

Soft QCD at Tevatron

Experimental studies of soft Quantum Chromodynamics (QCD) at Tevatron are reported in this note. Results on inclusive inelastic interactions, underlying events, double parton interaction and exclusive diffractive production and their implications to the Large Hadron Collider (LHC) physics are discussed.
Date: June 1, 2010
Creator: Rangel, Murilo
System: The UNT Digital Library
The Genome of Naegleria gruberi Illuminates Early Eukaryotic Versatility (open access)

The Genome of Naegleria gruberi Illuminates Early Eukaryotic Versatility

Genome sequences of diverse free-living protists are essential for understanding eukaryotic evolution and molecular and cell biology. The free-living amoeboflagellate Naegleria gruberi belongs to a varied and ubiquitous protist clade (Heterolobosea) that diverged from other eukaryotic lineages over a billion years ago. Analysis of the 15,727 protein-coding genes encoded by Naegleria's 41 Mb nuclear genome indicates a capacity for both aerobic respiration and anaerobic metabolism with concomitant hydrogen production, with fundamental implications for the evolution of organelle metabolism. The Naegleria genome facilitates substantially broader phylogenomic comparisons of free-living eukaryotes than previously possible, allowing us to identify thousands of genes likely present in the pan-eukaryotic ancestor, with 40% likely eukaryotic inventions. Moreover, we construct a comprehensive catalog of amoeboid-motility genes. The Naegleria genome, analyzed in the context of other protists, reveals a remarkably complex ancestral eukaryote with a rich repertoire of cytoskeletal, sexual, signaling, and metabolic modules.
Date: March 1, 2010
Creator: Fritz-Laylin, Lillian K.; Prochnik, Simon E.; Ginger, Michael L.; Dacks, Joel; Carpenter, Meredith L.; Field, Mark C. et al.
System: The UNT Digital Library
Development of a Standard for Verification and Validation of Software Used to Calculate Nuclear System Thermal Fluids Behavior (open access)

Development of a Standard for Verification and Validation of Software Used to Calculate Nuclear System Thermal Fluids Behavior

With the resurgence of nuclear power and increased interest in advanced nuclear reactors as an option to supply abundant energy without the associated greenhouse gas emissions of the more conventional fossil fuel energy sources, there is a need to establish internationally recognized standards for the verification and validation (V&V) of software used to calculate the thermal-hydraulic behavior of advanced reactor designs for both normal operation and hypothetical accident conditions. To address this need, ASME (American Society of Mechanical Engineers) Standards and Certification has established the V&V 30 Committee, under the responsibility of the V&V Standards Committee, to develop a consensus Standard for verification and validation of software used for design and analysis of advanced reactor systems. The initial focus of this committee will be on the V&V of system analysis and computational fluid dynamics (CFD) software for nuclear applications. To limit the scope of the effort, the committee will further limit its focus to software to be used in the licensing of High-Temperature Gas-Cooled Reactors. In this framework, the standard should conform to Nuclear Regulatory Commission (NRC) practices, procedures and methods for licensing of nuclear power plants as embodied in the United States (U.S.) Code of Federal Regulations and other …
Date: May 1, 2010
Creator: Schultz, Richard R.; Harvego, Edwin A. & Crane, Ryan L.
System: The UNT Digital Library
Critical Currents of YBCO Tapes and Bi-2212 Wires at Different Temperatures and Magnetic Fields (open access)

Critical Currents of YBCO Tapes and Bi-2212 Wires at Different Temperatures and Magnetic Fields

Design studies for the cooling channel of a Muon Collider call for straight and helical solenoids generating field well in excess of the critical fields of state of the art Low Temperature Superconductors (LTS) such as Nb{sub 3}Sn or NbTi. Therefore, High Temperature Superconductors (HTS) will need to be used for the manufacturing of all or certain sections of such magnets to be able to generate and withstand the field levels at the cryogenic temperatures required by the new machine. In this work, two major High Temperature Superconductors - Bi2212 round wires and YBCO coated conductor tapes - are investigated to understand how critical current density of such conductors scales as a function of external field and operating temperature. This is vital information to make conductor choices depending on the application and to proceed with the design of such magnets.
Date: August 1, 2010
Creator: Lombardo, V.; Barzi, E.; Turrioni, D. & Zlobin, A. V.
System: The UNT Digital Library
Enumerating a Diverse Set of Building Designs Using Discrete Optimization: Preprint (open access)

Enumerating a Diverse Set of Building Designs Using Discrete Optimization: Preprint

Numerical optimization is a powerful method for identifying energy-efficient building designs. Automating the search process facilitates the evaluation of many more options than is possible with one-off parametric simulation runs. However, input data uncertainties and qualitative aspects of building design work against standard optimization formulations that return a single, so-called optimal design. This paper presents a method for harnessing a discrete optimization algorithm to obtain significantly different, economically viable building designs that satisfy an energy efficiency goal. The method is demonstrated using NREL's first-generation building analysis platform, Opt- E-Plus, and two example problems. We discuss the information content of the results, and the computational effort required by the algorithm.
Date: August 1, 2010
Creator: Hale, E. & Long, N.
System: The UNT Digital Library
A low-threshold analysis of CDMS shallow-site data (open access)

A low-threshold analysis of CDMS shallow-site data

Data taken during the final shallow-site run of the first tower of the Cryogenic Dark Matter Search (CDMS II) detectors have been reanalyzed with improved sensitivity to small energy depositions. Four {approx}224 g germanium and two {approx}105 g silicon detectors were operated at the Stanford Underground Facility (SUF) between December 2001 and June 2002, yielding 118 live days of raw exposure. Three of the germanium and both silicon detectors were analyzed with a new low-threshold technique, making it possible to lower the germanium and silicon analysis thresholds down to the actual trigger thresholds of {approx}1 keV and {approx}2 keV, respectively. Limits on the spin-independent cross section for weakly interacting massive particles (WIMPs) to elastically scatter from nuclei based on these data exclude interesting parameter space for WIMPs with masses below 9 GeV/c{sup 2}. Under standard halo assumptions, these data partially exclude parameter space favored by interpretations of the DAMA/LIBRA and CoGeNT experiments data as WIMP signals, and exclude new parameter space for WIMP masses between 3 GeV/c{sup 2} and 4 GeV/c{sup 2}.
Date: October 1, 2010
Creator: Akerib, D. S.; Attisha, M. J.; Baudis, L.; Bauer, D. A.; Bolozdynya, A. I.; Brink, P. L. et al.
System: The UNT Digital Library
Utilizing Load Response for Wind and Solar Integration and Power System Reliability (open access)

Utilizing Load Response for Wind and Solar Integration and Power System Reliability

Responsive load is still the most underutilized reliability resource in North America. This paper examines the characteristics of concern to the power system, the renewables, and to the loads.
Date: July 1, 2010
Creator: Milligan, M. & Kirby, B.
System: The UNT Digital Library
The Statistical Analysis Techniques to Support the NGNP Fuel Performance Experiments (open access)

The Statistical Analysis Techniques to Support the NGNP Fuel Performance Experiments

This paper describes the development and application of statistical analysis techniques to support the AGR experimental program on NGNP fuel performance. The experiments conducted in the Idaho National Laboratory’s Advanced Test Reactor employ fuel compacts placed in a graphite cylinder shrouded by a steel capsule. The tests are instrumented with thermocouples embedded in graphite blocks and the target quantity (fuel/graphite temperature) is regulated by the He-Ne gas mixture that fills the gap volume. Three techniques for statistical analysis, namely control charting, correlation analysis, and regression analysis, are implemented in the SAS-based NGNP Data Management and Analysis System (NDMAS) for automated processing and qualification of the AGR measured data. The NDMAS also stores daily neutronic (power) and thermal (heat transfer) code simulation results along with the measurement data, allowing for their combined use and comparative scrutiny. The ultimate objective of this work includes (a) a multi-faceted system for data monitoring and data accuracy testing, (b) identification of possible modes of diagnostics deterioration and changes in experimental conditions, (c) qualification of data for use in code validation, and (d) identification and use of data trends to support effective control of test conditions with respect to the test target. Analysis results and examples …
Date: June 1, 2010
Creator: Pham, Bihn T. & Einerson, Jeffrey J.
System: The UNT Digital Library
Top quark physics: from Tevatron to LHC (open access)

Top quark physics: from Tevatron to LHC

None
Date: October 1, 2010
Creator: Shabalina, E.K. & /Gottingen U., II. Phys. Inst.
System: The UNT Digital Library
Latest highlights from CDF (open access)

Latest highlights from CDF

The CDF II experiment at the Fermilab Tevatron collider has been running steadily for many years accumulating large datasets which allow to probe many facets of the Standard Model and its possible extensions over a wide range of processes. This contribution presents an overview of the CDF physics program focusing on the most recent results as of April 2010. The CDF II experiment at the Fermilab Tevatron collider has been steadily acquiring data since the beginning of 2002. The large accumulated datasets allow CDF to pursue a very rich and broad physics program, which is probing many facets of the Standard Model (SM) and its possible extensions over a wide range of processes, whose cross sections span over 10 orders of magnitude, from the tens of millibarns of the total p {bar p} cross section to the fraction of a picobarn expected for the production of the SM Higgs boson. The CDF investigation of the fundamental constituents of matter is organized on the basis of the phenomena and the sector of the Standard Model which are being explored: the study of the strong interactions between the quarks and gluons in the colliding nucleons, the b- and c-quark flavor physics, the …
Date: July 1, 2010
Creator: Casarsa, Massimo
System: The UNT Digital Library
CMS centres worldwide: A new collaborative infrastructure (open access)

CMS centres worldwide: A new collaborative infrastructure

The CMS Experiment at the LHC is establishing a global network of inter-connected 'CMS Centres' for controls, operations and monitoring. These support: (1) CMS data quality monitoring, detector calibrations, and analysis; and (2) computing operations for the processing, storage and distribution of CMS data. We describe the infrastructure, computing, software, and communications systems required to create an effective and affordable CMS Centre. We present our highly successful operations experiences with the major CMS Centres at CERN, Fermilab, and DESY during the LHC first beam data-taking and cosmic ray commissioning work. The status of the various centres already operating or under construction in Asia, Europe, Russia, South America, and the USA is also described. We emphasise the collaborative communications aspects. For example, virtual co-location of experts in CMS Centres Worldwide is achieved using high-quality permanently-running 'telepresence' video links. Generic Web-based tools have been developed and deployed for monitoring, control, display management and outreach.
Date: January 1, 2010
Creator: Taylor, Lucas & Gottschalk, Erik
System: The UNT Digital Library
An implementation of co-simulation for performance prediction of innovative integrated HVAC systems in buildings (open access)

An implementation of co-simulation for performance prediction of innovative integrated HVAC systems in buildings

Integrated performance simulation of buildings and heating, ventilation and air-conditioning (HVAC) systems can help reducing energy consumption and increasing level of occupant comfort. However, no singe building performance simulation (BPS) tool offers sufficient capabilities and flexibilities to accommodate the ever-increasing complexity and rapid innovations in building and system technologies. One way to alleviate this problem is to use co-simulation. The co-simulation approach represents a particular case of simulation scenario where at least two simulators solve coupled differential-algebraic systems of equations and exchange data that couples these equations during the time integration. This paper elaborates on issues important for co-simulation realization and discusses multiple possibilities to justify the particular approach implemented in a co-simulation prototype. The prototype is verified and validated against the results obtained from the traditional simulation approach. It is further used in a case study for the proof-of-concept, to demonstrate the applicability of the method and to highlight its benefits. Stability and accuracy of different coupling strategies are analyzed to give a guideline for the required coupling frequency. The paper concludes by defining requirements and recommendations for generic cosimulation implementations.
Date: July 1, 2010
Creator: Trcka, Marija; Wetter, Michael & Hensen, Jan L. M.
System: The UNT Digital Library
Evidence for an anomalous like-sign dimuon charge asymmetry (open access)

Evidence for an anomalous like-sign dimuon charge asymmetry

None
Date: July 1, 2010
Creator: Abazov, Victor Mukhamedovich; Abbott, Braden Keim; Abolins, Maris A.; Acharya, Bannanje Sripath; Adams, Mark Raymond; Adams, Todd et al.
System: The UNT Digital Library
Modeling the U.S. Rooftop Photovoltaics Market (open access)

Modeling the U.S. Rooftop Photovoltaics Market

Global rooftop PV markets are growing rapidly, fueled by a combination of declining PV prices and several policy-based incentives. The future growth, and size, of the rooftop market is highly dependent on continued PV cost reductions, financing options, net metering policy, carbon prices and future incentives. Several PV market penetration models, sharing a similar structure and methodology, have been developed over the last decade to quantify the impacts of these factors on market growth. This study uses a geospatially rich, bottom-up, PV market penetration model--the Solar Deployment Systems (SolarDS) model developed by the National Renewable Energy Laboratory--to explore key market and policy-based drivers for residential and commercial rooftop PV markets. The identified drivers include a range of options from traditional incentives, to attractive customer financing options, to net metering and carbon policy.
Date: September 1, 2010
Creator: Drury, E.; Denholm, P. & Margolis, R.
System: The UNT Digital Library
Scalability and interoperability within glideinWMS (open access)

Scalability and interoperability within glideinWMS

Physicists have access to thousands of CPUs in grid federations such as OSG and EGEE. With the start-up of the LHC, it is essential for individuals or groups of users to wrap together available resources from multiple sites across multiple grids under a higher user-controlled layer in order to provide a homogeneous pool of available resources. One such system is glideinWMS, which is based on the Condor batch system. A general discussion of glideinWMS can be found elsewhere. Here, we focus on recent advances in extending its reach: scalability and integration of heterogeneous compute elements. We demonstrate that the new developments exceed the design goal of over 10,000 simultaneous running jobs under a single Condor schedd, using strong security protocols across global networks, and sustaining a steady-state job completion rate of a few Hz. We also show interoperability across heterogeneous computing elements achieved using client-side methods. We discuss this technique and the challenges in direct access to NorduGrid and CREAM compute elements, in addition to Globus based systems.
Date: January 1, 2010
Creator: Bradley, D.; Sfiligoi, I.; Padhi, S.; Frey, J. & Tannenbaum, T.
System: The UNT Digital Library
Design, Installation, and Initial Commissioning of the MTA Beamline (open access)

Design, Installation, and Initial Commissioning of the MTA Beamline

A new experimental area designed to develop, test and verify muon ionization cooling apparatus using the 400-MeV Fermilab Linac proton beam has been fully installed and is presently being commissioned. Initially, this area was used for cryogenic tests of liquid-hydrogen absorbers for the MUCOOL R&D program and, now, for high-power beam tests of absorbers, high-gradient rf cavities in the presence of magnetic fields (including gas-filled cavities), and other prototype muon-cooling apparatus. The experimental scenarios being developed for muon facilities involve collection, capture, and cooling of large-emittance, high-intensity muon beams--{approx}10{sup 13} muons, so that conclusive tests of the apparatus require full Linac beam, which is 1.6 x 10{sup 13} p/pulse. To support the muon cooling facility, this new primary beamline extracts and transports beam directly from the Linac to the test facility. The design concept for the MuCool facility is taken from an earlier proposal [1], but modifications were necessary to accommodate high-intensity beam, cryogenics, and the increased scale of the cooling experiments. Further, the line incorporates a specialized section and utilizes a different mode of operation to provide precision measurements of Linac beam parameters. This paper reports on the technical details of the MuCool beamline for both modes.
Date: May 1, 2010
Creator: Moore, Craig D.; Anderson, John; Garcia, Fernanda; Gerardi, Michael; Johnstone, Carol; Kobilarcik, Thomas et al.
System: The UNT Digital Library
Developing an Instrumentation Package for in-Water Testing of Marine Hydrokinetic Energy Devices: Preprint (open access)

Developing an Instrumentation Package for in-Water Testing of Marine Hydrokinetic Energy Devices: Preprint

The ocean-energy industry is still in its infancy and device developers have provided their own equipment and procedures for testing. Currently, no testing standards exist for ocean energy devices in the United States. Furthermore, as prototype devices move from the test tank to in-water testing, the logistical challenges and costs grow exponentially. Development of a common instrumentation package that can be moved from device to device is one means of reducing testing costs and providing normalized data to the industry as a whole. As a first step, the U.S. National Renewable Energy Laboratory (NREL) has initiated an effort to develop an instrumentation package to provide a tool to allow common measurements across various ocean energy devices. The effort is summarized in this paper. First, we present the current status of ocean energy devices. We then review the experiences of the wind industry in its development of the instrumentation package and discuss how they can be applied in the ocean environment. Next, the challenges that will be addressed in the development of the ocean instrumentation package are discussed. For example, the instrument package must be highly adaptable to fit a large array of devices but still conduct common measurements. Finally, some …
Date: August 1, 2010
Creator: Nelson, E.
System: The UNT Digital Library