Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200 (open access)

Observation of Two-Neutrino Double-Beta Decay in Xe-136 with EXO-200

We report the observation of two-neutrino double-beta decay in {sup 136}Xe with T{sub 1/2} = 2.11 {+-} 0.04(stat) {+-} 0.21(syst) x 10{sup 21} yr. This second-order process, predicted by the standard model, has been observed for several nuclei but not for {sup 136}Xe. The observed decay rate provides new input to matrix element calculations and to the search for the more interesting neutrinoless double-beta decay, the most sensitive probe for the existence of Majorana particles and the measurement of the neutrino mass scale.
Date: September 14, 2012
Creator: Ackerman, N.; Aharmim, B.; Auger, M.; Auty, D. J.; Barbeau, P. S.; Barry, K. et al.
Object Type: Article
System: The UNT Digital Library
Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope (open access)

Constraining Dark Matter Models from a Combined Analysis of Milky Way Satellites with the Fermi Large Area Telescope

Satellite galaxies of the Milky Way are among the most promising targets for dark matter searches in gamma rays. We present a search for dark matter consisting of weakly interacting massive particles, applying a joint likelihood analysis to 10 satellite galaxies with 24 months of data of the Fermi Large Area Telescope. No dark matter signal is detected. Including the uncertainty in the dark matter distribution, robust upper limits are placed on dark matter annihilation cross sections. The 95% confidence level upper limits range from about 10{sup -26} cm{sup 3} s{sup -1} at 5 GeV to about 5 x 10{sup -23} cm{sup 3} s{sup -1} at 1 TeV, depending on the dark matter annihilation final state. For the first time, using gamma rays, we are able to rule out models with the most generic cross section ({approx}3 x 10{sup -26} cm{sup 3} s{sup -1} for a purely s-wave cross section), without assuming additional boost factors.
Date: September 14, 2012
Creator: Ackermann, M.; Ajello, M.; Albert, A.; Atwood, W. B.; Baldini, L.; Ballet, J. et al.
Object Type: Article
System: The UNT Digital Library
Gravitomagnetism and Spinor Quantum Mechanics (open access)

Gravitomagnetism and Spinor Quantum Mechanics

We give a systematic treatment of a spin 1=2 particle in a combined electromagnetic field and a weak gravitational field that is produced by a slowly moving matter source. This paper continues previous work on a spin zero particle, but it is largely self-contained and may serve as an introduction to spinors in a Riemann space. The analysis is based on the Dirac equation expressed in generally covariant form and coupled minimally to the electromagnetic field. The restriction to a slowly moving matter source, such as the earth, allows us to describe the gravitational field by a gravitoelectric (Newtonian) potential and a gravitomagnetic (frame-dragging) vector potential, the existence of which has recently been experimentally verified. Our main interest is the coupling of the orbital and spin angular momenta of the particle to the gravitomagnetic field. Specifically we calculate the gravitational gyromagnetic ratio as g{sub g} = 1 ; this is to be compared with the electromagnetic gyromagnetic ratio of g{sub e} = 2 for a Dirac electron.
Date: September 14, 2012
Creator: Adler, Ronald J.; /Stanford U., HEPL /San Francisco State U.; Chen, Pisin; /Taiwan, Natl. Taiwan U. /KIPAC, Menlo Park /SLAC; Varani, Elisa & /Unlisted
Object Type: Article
System: The UNT Digital Library
The Future of the Eurozone and U.S. Interests (open access)

The Future of the Eurozone and U.S. Interests

This report details the consequences of the European financial crisis of 2010 beginning with the economic fallout of the Greek economy. It then highlights six factors that would be instrumental regarding the "Eurozones" future.
Date: September 14, 2010
Creator: Ahearn, Raymond J.; Jackson, James K.; Nelson, Rebecca M. & Weiss, Martin A.
Object Type: Report
System: The UNT Digital Library
Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1 (open access)

Fermi Large Area Telescope Observations of the Supernova Remnant G8.7-0.1

We present a detailed analysis of the GeV gamma-ray emission toward the supernova remnant (SNR) G8.7-0.1 with the Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope. An investigation of the relationship between G8.7-0.1 and the TeV unidentified source HESS J1804-216 provides us with an important clue on diffusion process of cosmic rays if particle acceleration operates in the SNR. The GeV gamma-ray emission is extended with most of the emission in positional coincidence with the SNR G8.7-0.1 and a lesser part located outside the western boundary of G8.7-0.1. The region of the gamma-ray emission overlaps spatially connected molecular clouds, implying a physical connection for the gamma-ray structure. The total gamma-ray spectrum measured with LAT from 200 MeV-100 GeV can be described by a broken power-law function with a break of 2.4 {+-} 0.6 (stat) {+-} 1.2 (sys) GeV, and photon indices of 2.10 {+-} 0.06 (stat) {+-} 0.10 (sys) below the break and 2.70 {+-} 0.12 (stat) {+-} 0.14 (sys) above the break. Given the spatial association among the gamma rays, the radio emission of G8.7-0.1, and the molecular clouds, the decay of p0s produced by particles accelerated in the SNR and hitting the molecular clouds naturally …
Date: September 14, 2012
Creator: Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D. et al.
Object Type: Article
System: The UNT Digital Library
Higgs, Binos and Gluinos: Split Susy within Reach (open access)

Higgs, Binos and Gluinos: Split Susy within Reach

Recent results from the LHC for the Higgs boson with mass between 142 GeV {approx}< m{sub h{sup 0}} {approx}< 147 GeV points to PeV-scale Split Supersymmetry. This article explores the consequences of a Higgs mass in this range and possible discovery modes for Split Susy. Moderate lifetime gluinos, with decay lengths in the 25 {micro}m to 10 yr range, are its imminent smoking gun signature. The 7TeV LHC will be sensitive to the moderately lived gluinos and trilepton signatures from direct electroweakino production. Moreover, the dark matter abundance may be obtained from annihilation through an s-channel Higgs resonance, with the LSP almost purely bino and mass m{sub {chi}{sub 1}{sup 0}} {approx_equal} 70 GeV. The Higgs resonance region of Split Susy has visible signatures in dark matter direct and indirect detection and electric dipole moment experiments. If the anomalies go away, the majority of Split Susy parameter space will be excluded.
Date: September 14, 2012
Creator: Alves, Daniele S.M.; Izaguirre, Eder; /SLAC /Stanford U., Phys. Dept.; Wacker, Jay G. & /SLAC /Stanford U., ITP
Object Type: Article
System: The UNT Digital Library
NEPHELINE NUCLEATION AND CRYSTAL GROWTH IN WASTE GLASSES: INTERIM REPORT (open access)

NEPHELINE NUCLEATION AND CRYSTAL GROWTH IN WASTE GLASSES: INTERIM REPORT

None
Date: September 14, 2011
Creator: Amoroso, J.
Object Type: Report
System: The UNT Digital Library
Running Deficits: Positives and Pitfalls (open access)

Running Deficits: Positives and Pitfalls

The FY2009 federal deficit swelled to $1.414 trillion, or nearly 10% of gross domestic product (GDP), due to the economic recession. The size of recent deficits has added to longstanding concerns regarding the federal government's long-term fiscal condition. However, deficit finance can serve as an important policy tool. This report discusses how deficit finance can help governments manage their economies and how large and persistent deficits can lead to severe economic problems.
Date: September 14, 2010
Creator: Austin, D. Andrew
Object Type: Report
System: The UNT Digital Library
Trends in Mandatory Spending: In Brief (open access)

Trends in Mandatory Spending: In Brief

This report describes mandatory spending, its composition and growth over time, and possible mandatory spending in coming decades, as well as relevant policy options.
Date: September 14, 2018
Creator: Austin, D. Andrew
Object Type: Report
System: The UNT Digital Library
Present Constraints on the H-dibaryon at the Physical Pointfrom Lattice QCD (open access)

Present Constraints on the H-dibaryon at the Physical Pointfrom Lattice QCD

None
Date: September 14, 2011
Creator: Beane, S.; Chang, E.; Detmold, W.; Joo, B.; Lin, H. W.; Luu, T. et al.
Object Type: Article
System: The UNT Digital Library
The Deuteron and Exotic Two-Body Bound States from Lattice QCD (open access)

The Deuteron and Exotic Two-Body Bound States from Lattice QCD

Results of a high-statistics,multi-volume Lattice QCD exploration of the deuteron, the di-neutron, the H-dibaryon are presented.
Date: September 14, 2011
Creator: Beane, S.; Chang, E.; Detmold, W.; Lin, H. W.; Luu, T.; Orginos, K. et al.
Object Type: Article
System: The UNT Digital Library
Prospects in Colombia: Cease-Fire, Peace Accord Vote, and Potential Disrupters (open access)

Prospects in Colombia: Cease-Fire, Peace Accord Vote, and Potential Disrupters

This report discusses the political situation in Colombia after a peace accord negotiated over four years between the government of President Juan Manuel Santos and the country's largest insurgent group, the Revolutionary Armed Forces of Colombia (FARC).
Date: September 14, 2016
Creator: Beittel, June S.
Object Type: Report
System: The UNT Digital Library
Election in Greece (open access)

Election in Greece

This report discusses issues leading up to Greece's snap legislative election on September 20, only eight months after the country's last election. Greece continues to struggle with the negative repercussions of a sovereign debt and financial crisis that began in 2009.
Date: September 14, 2015
Creator: Belkin, Paul
Object Type: Report
System: The UNT Digital Library
Precise Predictions for W 4 Jet Production at the Large Hadron Collider (open access)

Precise Predictions for W 4 Jet Production at the Large Hadron Collider

We present the first next-to-leading order QCD results for W + 4-jet production at hadron colliders. Total cross sections, as well as distributions in the jet transverse momenta and in the total transverse energy HT, are provided for the initial LHC energy of {radical}s = 7 TeV. We use a leading-color approximation, known to be accurate to 3% for W production with fewer jets. The virtual matrix elements and the most complicated real-emission matrix elements are handled by the BlackHat library, based on on-shell methods. The remaining parts of the calculation, including the integration over phase space, are performed by the SHERPA package.
Date: September 14, 2010
Creator: Berger, C.F.; /MIT, LNS; Bern, Z.; /UCLA; Dixon, Lance J.; /SLAC, /CERN et al.
Object Type: Article
System: The UNT Digital Library
Intelligence Issues for Congress (open access)

Intelligence Issues for Congress

This report gives an overview of current intelligence issues of interest to the 112th Congress. It includes background and analysis including most recent development, ongoing Congressional concerns, specific issues for the 112th Congress, and a summary of related legislation from the 109th through the 112th Congresses.
Date: September 14, 2011
Creator: Best, Richard A., Jr.
Object Type: Report
System: The UNT Digital Library
Unauthorized Childhood Arrivals: Legislative Options (open access)

Unauthorized Childhood Arrivals: Legislative Options

This report discusses bills proposed in Congress that either would provide temporary protection from removal or paths to citizenship for Deferred Action for Childhood Arrivals (DACA) recipients in the wake of the announcement of the phasing out of the DACA program.
Date: September 14, 2017
Creator: Bruno, Andorra
Object Type: Report
System: The UNT Digital Library
Study of B Decays to Open Charm Final States With the BaBar Experiment (open access)

Study of B Decays to Open Charm Final States With the BaBar Experiment

Recent results from the BaBar Collaboration in the sector of B decays to open Charm are presented. Some of the results represent new precision measurements and QCD tests, some other analysis is aimed to the study of rare decays and search for new physics. Branching fractions for the modes observed for the first time are highlighted. A few results are presented also in the baryon sector.
Date: September 14, 2011
Creator: Calderini, Giovanni & /INFN, Pisa /Pisa U.
Object Type: Article
System: The UNT Digital Library
Development of Production PVD-AIN Buffer Layer System and Processes to Reduce Epitaxy Costs and Increase LED Efficiency (open access)

Development of Production PVD-AIN Buffer Layer System and Processes to Reduce Epitaxy Costs and Increase LED Efficiency

The DOE has set aggressive goals for solid state lighting (SSL) adoption, which require manufacturing and quality improvements for virtually all process steps leading to an LED luminaire product. The goals pertinent to this proposed project are to reduce the cost and improve the quality of the epitaxial growth processes used to build LED structures. The objectives outlined in this proposal focus on achieving cost reduction and performance improvements over state-of-the-art, using technologies that are low in cost and amenable to high efficiency manufacturing. The objectives of the outlined proposal focus on cost reductions in epitaxial growth by reducing epitaxy layer thickness and hetero-epitaxial strain, and by enabling the use of larger, less expensive silicon substrates and would be accomplished through the introduction of a high productivity reactive sputtering system and an effective sputtered aluminum-nitride (AlN) buffer/nucleation layer process. Success of the proposed project could enable efficient adoption of GaN on-silicon (GaN/Si) epitaxial technology on 150mm silicon substrates. The reduction in epitaxy cost per cm{sup 2} using 150mm GaN-on-Si technology derives from (1) a reduction in cost of ownership and increase in throughput for the buffer deposition process via the elimination of MOCVD buffer layers and other throughput and CoO …
Date: September 14, 2013
Creator: Cerio, Frank
Object Type: Report
System: The UNT Digital Library
Afghanistan Casualties: Military Forces and Civilians (open access)

Afghanistan Casualties: Military Forces and Civilians

This report collects statistics from a variety of sources on casualties sustained during Operation Enduring Freedom (OEF), which began on October 7, 2001. OEF actions took place primarily in Afghanistan, but OEF casualties also include American casualties in other countries, listed within this report.
Date: September 14, 2010
Creator: Chesser, Susan G.
Object Type: Report
System: The UNT Digital Library
Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET (open access)

Plasmas, Dielectrics and the Ultrafast: First Science and Operational Experience at FACET

FACET (Facility for Advanced Accelerator and Experimental Tests) is an accelerator R&D test facility that has been recently constructed at SLAC National Accelerator Laboratory. The facility provides 20 GeV, 3 nC electron beams, short (20 {micro}m) bunches and small (20 {micro}m wide) spot sizes, producing uniquely high power beams. FACET supports studies from many fields but in particular those of Plasma Wakefield Acceleration and Dielectric Wakefield Acceleration. FACET is also a source of THz radiation for material studies. We present the FACET design, initial operating experience and first science from the facility.
Date: September 14, 2012
Creator: Clarke, C. I.; Adli, E.; Corde, S.; Decker, F. J.; England, R. J.; Erickson, R. et al.
Object Type: Article
System: The UNT Digital Library
Trade Adjustment Assistance for Workers and the TAA Reauthorization Act of 2015 (open access)

Trade Adjustment Assistance for Workers and the TAA Reauthorization Act of 2015

This report describes Trade Adjustment Assistance for Workers (TAA) as reauthorized by the Trade Adjustment Assistance Reauthorization Act of 2015.
Date: September 14, 2016
Creator: Collins, Benjamin
Object Type: Report
System: The UNT Digital Library
Powering Africa: Challenges of and U.S. Aid for Electrification in Africa (open access)

Powering Africa: Challenges of and U.S. Aid for Electrification in Africa

This report discusses the Power Africa initiative; policy problems and challenges related to power sector development in Africa; long-term perspectives on energy poverty, need, and future development; and raises some possible oversight questions and issues for Congress.
Date: September 14, 2015
Creator: Cook, Nicolas; Campbell, Richard J.; Brown, Phillip & Ratner, Michael
Object Type: Report
System: The UNT Digital Library
CO2 Removal using a Synthetic Analogue of Carbonic Anhydrase (open access)

CO2 Removal using a Synthetic Analogue of Carbonic Anhydrase

Project attempts to develop a synthetic analogue for carbonic anhydrase and incorporate it in a membrane for separation of CO2 from coal power plant flue gas. Conference poster presents result of first 9 months of project progress including concept, basic system architecture and membrane properties target, results of molecular modeling for analogue - CO2 interaction, and next steps of testing analogue resistance to flue gas contaminants.
Date: September 14, 2010
Creator: Cordatos, Harry
Object Type: Article
System: The UNT Digital Library
Mechanical Design of the HER Synchrotron Light Monitor Primary Mirror (open access)

Mechanical Design of the HER Synchrotron Light Monitor Primary Mirror

This paper describes the mechanical design of the primary mirror that images the visible portion of the synchrotron radiation (SR) extracted from the High Energy Ring (HER) of the PEP-II B-Factory. During off-axis operation, the water-cooled GlidCop mirror is subjected to a heat flux in excess of 2000 W/cm2. When on-axis imaging occurs, the heat flux due to scattered SR, resistive wall losses and Higher-Order-Mode (HOM) heating is estimated at 1 W/cm2. The imaging surface is plated with Electroless Nickel to improve its optical characteristics. The design requirements for the primary mirror are listed and discussed. Calculated mechanical distortions and stresses experienced by the mirror during on-axis and off-axis operation will be presented.
Date: September 14, 2011
Creator: Daly, Edward F.; Fisher, Alan S.; Kurita, Nadine R. & Langton, J.
Object Type: Article
System: The UNT Digital Library