Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas (open access)

Astrophysical Gyrokinetics: Kinetic and Fluid Turbulent Cascades In Magentized Weakly Collisional Plasmas

This paper presents a theoretical framework for understanding plasma turbulence in astrophysical plasmas. It is motivated by observations of electromagnetic and density fluctuations in the solar wind, interstellar medium and galaxy clusters, as well as by models of particle heating in accretion disks. All of these plasmas and many others have turbulentmotions at weakly collisional and collisionless scales. The paper focuses on turbulence in a strong mean magnetic field. The key assumptions are that the turbulent fluctuations are small compared to the mean field, spatially anisotropic with respect to it and that their frequency is low compared to the ion cyclotron frequency. The turbulence is assumed to be forced at some system-specific outer scale. The energy injected at this scale has to be dissipated into heat, which ultimately cannot be accomplished without collisions. A kinetic cascade develops that brings the energy to collisional scales both in space and velocity. The nature of the kinetic cascade in various scale ranges depends on the physics of plasma fluctuations that exist there. There are four special scales that separate physically distinct regimes: the electron and ion gyroscales, the mean free path and the electron diffusion scale. In each of the scale ranges separated …
Date: April 23, 2009
Creator: A.A. Schekochihin, S.C. Cowley, W. Dorland, G.W. Hammett, G.G. Howes, E. Quataert, and T. Tatsuno
Object Type: Report
System: The UNT Digital Library
Co-ordination of the International Network of Nuclear Structure and Decay Data Evaluators; Summary Report of an IAEA Technical Meeting (open access)

Co-ordination of the International Network of Nuclear Structure and Decay Data Evaluators; Summary Report of an IAEA Technical Meeting

The IAEA Nuclear Data Section convened the 18th meeting of the International Network of Nuclear Structure and Decay Data Evaluators at the IAEA Headquarters, Vienna, 23 to 27 March 2009. This meeting was attended by 22 scientists from 14 Member States, plus IAEA staff, concerned with the compilation, evaluation and dissemination of nuclear structure and decay data. A summary of the meeting, recommendations/conclusions, data centre reports, and various proposals considered, modified and agreed by the participants are contained within this document. The International Network of Nuclear Structure and Decay Data (NSDD) Evaluators holds biennial meetings under the auspices of the IAEA, and consists of evaluation groups and data service centres in several countries. This network has the objective of providing up-to-date nuclear structure and decay data for all known nuclides by evaluating all existing experimental data. Data resulting from this international evaluation collaboration is included in the Evaluated Nuclear Structure Data File (ENSDF) and published in the journals Nuclear Physics A and Nuclear Data Sheets (NDS).
Date: March 23, 2009
Creator: Abriola, D. & Tuli, J.
Object Type: Report
System: The UNT Digital Library
Performance of particle in cell methods on highly concurrent computational architectures (open access)

Performance of particle in cell methods on highly concurrent computational architectures

Particle in cell (PIC) methods are effective in computing Vlasov-Poisson system of equations used in simulations of magnetic fusion plasmas. PIC methods use grid based computations, for solving Poisson’s equation or more generally Maxwell’s equations, as well as Monte-Carlo type methods to sample the Vlasov equation. The presence of two types of discretizations, deterministic field solves and Monte-Carlo methods for the Vlasov equation, pose challenges in understanding and optimizing performance on today large scale computers which require high levels of concurrency. These challenges arises from the need to optimize two very different types of processes and the interactions between them. Modern cache based high-end computers have very deep memory hierarchies and high degrees of concurrency which must be utilized effectively to achieve good performance. The effective use of these machines requires maximizing concurrency by eliminating serial or redundant work and minimizing global communication. A related issue is minimizing the memory traffic between levels of the memory hierarchy because performance is often limited by the bandwidths and latencies of the memory system. This paper discusses some of the performance issues, particularly in regard to parallelism, of PIC methods. The gyrokinetic toroidal code (GTC) is used for these studies and a new …
Date: September 23, 2009
Creator: Adams, M. F.; Ethier, S. & Wichmann, N.
Object Type: Report
System: The UNT Digital Library
Lebanon: Background and U.S. Relations (open access)

Lebanon: Background and U.S. Relations

This report provides an overview of Lebanese politics, recent events in Lebanon, and current issues in U.S.-Lebanon relations and will be updated to reflect major developments.
Date: July 23, 2009
Creator: Addis, Casey L.
Object Type: Report
System: The UNT Digital Library
The Global Economic Downturn and Protectionism (open access)

The Global Economic Downturn and Protectionism

This report develops three scenarios to approximate different dimensions of the relationship between the global economic downturn and protectionism. The scenarios are not predictions, but descriptions of how and why pressures for protection could be manifested and transmitted under different circumstances and assumptions.
Date: March 23, 2009
Creator: Ahearn, Raymond J.
Object Type: Report
System: The UNT Digital Library
Time-Dependent Measure of a Nano-Scale Force-Pulse Driven by the Axonemal Dynein Motors in Individual Live Sperm Cells (open access)

Time-Dependent Measure of a Nano-Scale Force-Pulse Driven by the Axonemal Dynein Motors in Individual Live Sperm Cells

Nano-scale mechanical forces generated by motor proteins are crucial to normal cellular and organismal functioning. The ability to measure and exploit such forces would be important to developing motile biomimetic nanodevices powered by biological motors for Nanomedicine. Axonemal dynein motors positioned inside the sperm flagellum drive microtubule sliding giving rise to rhythmic beating of the flagellum. This force-generating action makes it possible for the sperm cell to move through viscous media. Here we report new nano-scale information on how the propulsive force is generated by the sperm flagellum and how this force varies over time. Single cell recordings reveal discrete {approx}50 ms pulses oscillating with amplitude 9.8 {+-} 2.6 nN independent of pulse frequency (3.5-19.5 Hz). The average work carried out by each cell is 4.6 x 10{sup -16} J per pulse, equivalent to the hydrolysis of {approx}5,500 ATP molecules. The mechanochemical coupling at each active dynein head is {approx}2.2 pN/ATP, and {approx}3.9 pN per dynein arm, in agreement with previously published values obtained using different methods.
Date: April 23, 2009
Creator: Allen, M J; Rudd, R E; McElfresh, M W & Balhorn, R
Object Type: Article
System: The UNT Digital Library
Multi-Channel Auto-Dilution System for Remote Continuous Monitoring of High Soil-CO2 Fluxes (open access)

Multi-Channel Auto-Dilution System for Remote Continuous Monitoring of High Soil-CO2 Fluxes

Geological sequestration has the potential capacity and longevity to significantly decrease the amount of anthropogenic CO2 introduced into the atmosphere by combustion of fossil fuels such as coal. Effective sequestration, however, requires the ability to verify the integrity of the reservoir and ensure that potential leakage rates are kept to a minimum. Moreover, understanding the pathways by which CO2 migrates to the surface is critical to assessing the risks and developing remediation approaches. Field experiments, such as those conducted at the Zero Emissions Research and Technology (ZERT) project test site in Bozeman, Montana, require a flexible CO2 monitoring system that can accurately and continuously measure soil-surface CO2 fluxes for multiple sampling points at concentrations ranging from background levels to several tens of percent. To meet this need, PNNL is developing a multi-port battery-operated system capable of both spatial and temporal monitoring of CO2 at concentrations from ambient to at least 150,000 ppmv. This report describes the system components (sampling chambers, measurement and control system, and power supply) and the results of a field test at the ZERT site during the late summer and fall of 2008. While the system performed well overall during the field test, several improvements to the …
Date: April 23, 2009
Creator: Amonette, James E. & Barr, Jonathan L.
Object Type: Report
System: The UNT Digital Library
Constraints on Inelastic Dark Matter from XENON10 (open access)

Constraints on Inelastic Dark Matter from XENON10

It has been suggested that dark matter particles which scatter inelastically from detector target nuclei could explain the apparent incompatibility of the DAMA modulation signal (interpreted as evidence for particle dark matter) with the null results from CDMS-II and XENON10. Among the predictions of inelastically interacting dark matter are a suppression of low-energy events, and a population of nuclear recoil events at higher nuclear recoil equivalent energies. This is in stark contrast to the well-known expectation of a falling exponential spectrum for the case of elastic interactions. We present a new analysis of XENON10 dark matter search data extending to E{sub nr} = 75 keV nuclear recoil equivalent energy. Our results exclude a significant region of previously allowed parameter space in the model of inelastically interacting dark matter. In particular, it is found that dark matter particle masses m{sub x} {approx}> 150 GeV are disfavored.
Date: November 23, 2009
Creator: Angle, J; Aprile, E; Arneodo, F; Baudis, L; Bernstein, A; Bolozdynya, A et al.
Object Type: Article
System: The UNT Digital Library
MINOR PARAMETERS NEEDED FOR INDIVIDUAL-DOSE CALCULATIONS: Final Report for Tasks 7.1, 7.2, 8.1, 8.2, 9.1, 9.2, and 9.3 (open access)

MINOR PARAMETERS NEEDED FOR INDIVIDUAL-DOSE CALCULATIONS: Final Report for Tasks 7.1, 7.2, 8.1, 8.2, 9.1, 9.2, and 9.3

This brief report documents the selection of parameters needed to support individual-dose calculations from 131I released into the environment with gaseous effluents from the Mayak Production Association.
Date: October 23, 2009
Creator: Anspaugh, L. R. & Napier, Bruce A.
Object Type: Report
System: The UNT Digital Library
Measurement of the Semileptonic Decays B->D tau nu and B->D* tau nu (open access)

Measurement of the Semileptonic Decays B->D tau nu and B->D* tau nu

The authors present measurements of the semileptonic decays B{sup -} {yields} D{sup 0} {tau}{sup -} {bar {nu}}{sub {tau}}, B{sup -} {yields} D*{sup 0} {tau}{sup -}{bar {nu}}{sub {tau}}, {bar B}{sup 0} {yields} D{sup +} {tau}{sup -} {bar {nu}}{sub {tau}}, and {bar B}{sup 0} {yields} D*{sup +} {tau}{sup -}{bar {nu}}{sub {tau}}, which are sensitive to non-Standard Model amplitudes in certain scenarios. The data sample consists of 232 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider. They select events with a D or D* meson and a light lepton ({ell} = e or {mu}) recoiling against a fully reconstructed B meson. They perform a fit to the joint distribution of lepton momentum and missing mass squared to distinguish signal B {yields} D{sup (*)}{tau}{sup -} {bar {nu}}{sub {tau}} ({tau}{sup -} {yields} {ell}{sup -} {bar {nu}}{sub {ell}}{nu}{sub {tau}}) events from the backgrounds, predominantly B {yields} D{sup (*)} {ell}{sup -}{bar {nu}}{sub {ell}}. They measure the branching-fraction ratios R(D) {triple_bond} {Beta}(B {yields} D{tau}{sup -} {bar {nu}}{sub {tau}})/{Beta}(B {yields} D{ell}{sup -} {bar {nu}}{sub {ell}}) and R(D*) {triple_bond} {Beta}(B {yields} D*{tau}{sup -} {bar {nu}}{sub {tau}})/{Beta}(B {yields} D* {ell}{sup -} {bar {nu}}{sub {ell}}) and, from a combined fit …
Date: February 23, 2009
Creator: Aubert, B.
Object Type: Article
System: The UNT Digital Library
Search for the decay B^+ \to K_S^0 K_S^0 \pi ^+ (open access)

Search for the decay B^+ \to K_S^0 K_S^0 \pi ^+

The authors search for charmless decays of charged B mesons to the three-body final state K{sub S}{sup 0}K{sub S}{sup 0}{pi}{sup +}. Using a data sample of 423.7 fb{sup -1} collected at the {Upsilon}(4S) resonance with the BABAR detector, corresponding to (465.1 {+-} 5.1) x 10{sup 6} B{bar B} pairs, they find no significant signal and determine a 90% confidence level upper limit on the branching fraction of 5.1 x 10{sup -7}.
Date: February 23, 2009
Creator: Aubert, B.; Bona, M.; Karyotakis, Y.; Lees, J. P.; Poireau, V.; Prencipe, E. et al.
Object Type: Article
System: The UNT Digital Library
Building America Best Practices Series, Volume 9: Builders Challenge Guide to 40% Whole-House Energy Savings in the Hot-Dry and Mixed-Dry Climates (open access)

Building America Best Practices Series, Volume 9: Builders Challenge Guide to 40% Whole-House Energy Savings in the Hot-Dry and Mixed-Dry Climates

This best practices guide is the ninth in a series of guides for builders produced by the U.S. Department of Energy’s Building America Program. This guide book is a resource to help builders design and construct homes that are among the most energy-efficient available, while addressing issues such as building durability, indoor air quality, and occupant health, safety, and comfort. With the measures described in this guide, builders in the hot-dry and mixed-dry climates can achieve homes that have whole house energy savings of 40% over the Building America benchmark (a home built to mid-1990s building practices roughly equivalent to the 1993 Model Energy Code) with no added overall costs for consumers. These best practices are based on the results of research and demonstration projects conducted by Building America’s research teams. The guide includes information for managers, designers, marketers, site supervisors, and subcontractors, as well as case studies of builders who are successfully building homes that cut energy use by 40% in the hot-dry and mixed-dry climates.
Date: October 23, 2009
Creator: Baechler, Michael C.; Gilbride, Theresa L.; Hefty, Marye G.; Williamson, Jennifer L.; Ruiz, Kathleen A.; Bartlett, Rosemarie et al.
Object Type: Report
System: The UNT Digital Library
Research Opportunities in High Energy Density Laboratory Plasmas on the NDCX-II Facility (open access)

Research Opportunities in High Energy Density Laboratory Plasmas on the NDCX-II Facility

Intense beams of heavy ions offer a very attractive tool for fundamental research in high energy density physics and inertial fusion energy science. These applications build on the significant recent advances in the generation, compression and focusing of intense heavy ion beams in the presence of a neutralizing background plasma. Such beams can provide uniform volumetric heating of the target during a time-scale shorter than the hydrodynamic response time, thereby enabling a significant suite of experiments that will elucidate the underlying physics of dense, strongly-coupled plasma states, which have been heretofore poorly understood and inadequately diagnosed, particularly in the warm dense matter regime. The innovations, fundamental knowledge, and experimental capabilities developed in this basic research program is also expected to provide new research opportunities to study the physics of directly-driven ion targets, which can dramatically reduce the size of heavy ion beam drivers for inertial fusion energy applications. Experiments examining the behavior of thin target foils heated to the warm dense matter regime began at the Lawrence Berkeley National Laboratory in 2008, using the Neutralized Drift Compression Experiment - I (NDCX-I) facility, and its associated target chamber and diagnostics. The upgrade of this facility, called NDCX-II, will enable an exciting …
Date: March 23, 2009
Creator: Barnard, John; Cohen, Ron; Friedman, Alex; Grote, Dave; Lund, Steven; Sharp, Bill et al.
Object Type: Report
System: The UNT Digital Library
Precise Predictions for W + 3 Jet Production at Hadron Colliders (open access)

Precise Predictions for W + 3 Jet Production at Hadron Colliders

We report on the first next-to-leading order QCD computation of W + 3-jet production in hadronic collisions including all partonic subprocesses. We compare the results with CDF data from the Tevatron, and find excellent agreement. The renormalization and factorization scale dependence is reduced substantially compared to leading-order calculations. The required one-loop matrix elements are computed using on-shell methods, implemented in a numerical program, BlackHat. We use the SHERPA package to generate the real-emission contributions and to integrate the various contributions over phase space. We use a leading-color (large-N{sub c}) approximation for the virtual part, which we confirm in W + 1,2-jet production to be valid to within three percent. The present calculation demonstrates the utility of on-shell methods for computing next-to-leading-order corrections to processes important to physics analyses at the Large Hadron Collider.
Date: February 23, 2009
Creator: Berger, C.F.; /MIT, LNS; Bern, Z.; /UCLA; Dixon, L.J.; /SLAC et al.
Object Type: Article
System: The UNT Digital Library
The United Arab Emirates Nuclear Program and Proposed U.S. Nuclear Cooperation (open access)

The United Arab Emirates Nuclear Program and Proposed U.S. Nuclear Cooperation

This report provides background information on the United Arab Emirates (UAE) and U.S. and it discusses the UAE nuclear program and the proposed U.S.-UAE cooperation.
Date: December 23, 2009
Creator: Blanchard, Christopher M. & Kerr, Paul K.
Object Type: Report
System: The UNT Digital Library
Manufacture of Alumina-Forming Austenitic Stainless Steel Alloys by Conventional Casting and Hot-Working Methods (open access)

Manufacture of Alumina-Forming Austenitic Stainless Steel Alloys by Conventional Casting and Hot-Working Methods

Oak Ridge National Laboratory (ORNL) and Carpenter Technology Corporation (CarTech) participated in an in-kind cost share cooperative research and development agreement (CRADA) effort under the auspices of the Energy Efficiency and Renewable Energy (EERE) Technology Maturation program to explore the feasibility for scale up of developmental ORNL alumina-forming austenitic (AFA) stainless steels by conventional casting and rolling techniques. CarTech successfully vacuum melted 30lb heats of four AFA alloy compositions in the range of Fe-(20-25)Ni-(12-14)Cr-(3-4)Al-(1-2.5)Nb wt.% base. Conventional hot/cold rolling was used to produce 0.5-inch thick plate and 0.1-inch thick sheet product. ORNL subsequently successfully rolled the 0.1-inch sheet to 4 mil thick foil. Long-term oxidation studies of the plate form material were initiated at 650, 700, and 800 C in air with 10 volume percent water vapor. Preliminary results indicated that the alloys exhibit comparable (good) oxidation resistance to ORNL laboratory scale AFA alloy arc casting previously evaluated. The sheet and foil material will be used in ongoing evaluation efforts for oxidation and creep resistance under related CRADAs with two gas turbine engine manufacturers. This work will be directed to evaluation of AFA alloys for use in gas turbine recuperators to permit higher-temperature operating conditions for improved efficiencies and reduced …
Date: March 23, 2009
Creator: Brady, M.P.; Yamamoto, Y. & Magee, J.H. (Carpenter Technol. Corp.)
Object Type: Report
System: The UNT Digital Library
Interfacial Phenomena: Linking Atomistic and Molecular Level Processes (open access)

Interfacial Phenomena: Linking Atomistic and Molecular Level Processes

This was a grant to support travel for scientists to present data and interact with others in their field. Specifically, speakers presented their data in a session entitled “Interfacial Phenomena: Linking Atomistic and Macroscopic Properties: Theoretical and Experimental Studies of the Structure and Reactivity of Mineral Surfaces”. The session ran across three ½ day periods, March 30-31 2004. The session’s organizers were David J. Wesolowski andGordon E. Brown Jr. There were a total of 30 talks presented.
Date: September 23, 2009
Creator: Brandes, Jay A
Object Type: Report
System: The UNT Digital Library
Inspection 13.2 nm table-top full-field microscope (open access)

Inspection 13.2 nm table-top full-field microscope

We present results on a table-top microscope that uses an EUV stepper geometry to capture full-field images with a halfpitch spatial resolution of 55 nm. This microscope uses a 13.2 nm wavelength table-top laser for illumination and acquires images of reflective masks with exposures of 20 seconds. These experiments open the path to the realization of high resolution table-top imaging systems for actinic defect characterization.
Date: February 23, 2009
Creator: Brizuela, F.; Wang, Y.; Brewer, C. A.; Pedaci, F.; Chao, W.; Anderson, E. H. et al.
Object Type: Article
System: The UNT Digital Library
AdS/CFT and Light-Front Holography: A Theory of Strong Interactions (open access)

AdS/CFT and Light-Front Holography: A Theory of Strong Interactions

Recent developments in the theory of strong interactions are discussed in the framework of the AdS/CFT duality between string theories of gravity in a higher dimension Anti-de Sitter space and conformal quantum field theories in physical space-time. This novel theoretical approach, combined with 'light-front holography', leads to new insights into the quark and gluon structure of hadrons and a viable first approximation to quantum chromodynamics, the fundamental theory of the strong and nuclear interactions.
Date: February 23, 2009
Creator: Brodsky, Stanley J. & Teramond, Guy F.de
Object Type: Article
System: The UNT Digital Library
Imaging of magnetic DW injection processed in patterened Ni80Fe20 structures (open access)

Imaging of magnetic DW injection processed in patterened Ni80Fe20 structures

Magnetization reversal in patterned ferromagnetic nanowires usually occurs via domain wall (DW) nucleation and propagation from one end (or both ends) of the wire which can be significantly reduced by a large, magnetically soft pad on one of the wire ends. These 'nucleation pads' reverse at lower fields than an isolated nanowire and introduce a DW to the wire from the wire end attached to the pad. Once a critical 'injection' field is reached, the DW sweeps through the wire, reversing its magnetization. Nucleation pads are frequently used as part of nanowire devices and experimental structures. Magnetic-field-driven shift register memory can include an injection pad to write data while those attached to nanowire spiral turn sensors act as both a source and sink of domain walls. Both of these devices use two-dimensional wire circuits and therefore require the use of orthogonal in-plane magnetic fields to drive domain walls through wires of different orientations. These bi-axial fields can significantly alter the fields at which DW injection occurs and control the number of different injection modes. We have used magnetic transmission soft X-ray microscopy (M-TXM) [6] providing 25nm spatial resolution to image the evolution of magnetization configurations in patterned 24nm thick Ni{sub …
Date: March 23, 2009
Creator: Bryan, M. T.; Basu, S.; Fry, P. W.; Schrefl, T.; Gibbs, M.R.J.; Allwood, D. A. et al.
Object Type: Article
System: The UNT Digital Library
LASER ABLATION-INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROSCOPY STUDY AT THE 222-S LABORATORY USING HOT-CELL GLOVE BOX PROTOTYPE SYSTEM (open access)

LASER ABLATION-INDUCTIVELY COUPLED PLASMA-ATOMIC EMISSION SPECTROSCOPY STUDY AT THE 222-S LABORATORY USING HOT-CELL GLOVE BOX PROTOTYPE SYSTEM

This report describes the installation, testing, and acceptance of the Waste Treatment and Immobilization Plant (WTP) procured laser ablation-inductively coupled plasma-atomic emission spectroscopy (LA-ICP-AES) system for remotely analyzing high-level waste (HLW) samples in a hot cell environment. The work was completed by the Analytical Process Development (APD) group in accordance with Task Order 2005-003; ATS MP 1027, Management Plan for Waste Treatment Plant Project Work Performed by Analytical Technical Services. The APD group at the 222-S Laboratory demonstrated acceptable turnaround time (TAT) and provide sufficient data to assess sensitivity, accuracy, and precision of the LA-ICP-AES method.
Date: February 23, 2009
Creator: CM, SEIDEL; J, JAIN & JW, OWENS
Object Type: Report
System: The UNT Digital Library
Scalable Methods for Electronic Excitations and Optical Responses of Nanstructures: Mathematics to Algorithms to Observables (open access)

Scalable Methods for Electronic Excitations and Optical Responses of Nanstructures: Mathematics to Algorithms to Observables

This multi-investigator project was concerned with the development and application of new methods and computer codes that would allow realistic modeling of nanosystems. Carter's part in this team effort involved two method/algorithm/code development projects during the first 14 months of this grant. Carter's group has been advancing theory and applications of the orbital-free density functional theory (OF-DFT), the only DFT method that exhibits linear scaling for metals. Such a method offers the possibility of simulating large numbers of atoms with quantum mechanics, such that properties of metallic nanostructures (e.g. nanowires of realistic dimensions) could be investigated. In addition, her group has been developing and applying an embedded correlated wavefunction theory for treating localized excited states in condensed matter (including metals). The application of interest here is spin manipulation at the nanoscale, i.e., spintronics, in which local electron excitations interact with the surrounding material. Her embedded correlation method is ideal for studying such problems.
Date: January 23, 2009
Creator: Carter, Emily A.
Object Type: Report
System: The UNT Digital Library
Simulating SiD Calorimetry: Software Calibration Procedures and Jet Energy Resolution (open access)

Simulating SiD Calorimetry: Software Calibration Procedures and Jet Energy Resolution

Simulated calorimeter performance in the SiD detector is examined. The software calibration procedures are described, as well as the perfect pattern recognition PFA reconstruction. Performance of the SiD calorimeters is summarized with jet energy resolutions from calorimetry only, perfect pattern recognition and the SiD PFA algorithm. Presented at LCWS08[1]. Our objective is to simulate the calorimeter performance of the SiD detector, with and without a Particle Flow Algorithm (PFA). Full Geant4 simulations using SLIC[2] and the SiD simplified detector geometry (SiD02) are used. In this geometry, the calorimeters are represented as layered cylinders. The EM calorimeter is Si/W, with 20 layers of 2.5mm W and 10 layers of 5mm W, segmented in 3.5 x 3.5mm{sup 2} cells. The HAD calorimeter is RPC/Fe, with 40 layers of 20mm Fe and a digital readout, segmented in 10 x 10mm{sup 2} cells. The barrel detectors are layered in radius, while the endcap detectors are layered in z(along the beam axis).
Date: February 23, 2009
Creator: Cassell, Ron
Object Type: Article
System: The UNT Digital Library
Duality, Entropy and ADM Mass in Supergravity (open access)

Duality, Entropy and ADM Mass in Supergravity

We consider the Bekenstein-Hawking entropy-area formula in four dimensional extended ungauged supergravity and its electric-magnetic duality property. Symmetries of both"large" and"small" extremal black holes are considered, as well as the ADM mass formula for N=4 and N=8 supergravity, preserving different fraction of supersymmetry. The interplay between BPS conditions and duality properties is an important aspect of this investigation.
Date: February 23, 2009
Creator: Cerchiai, Bianca L.; Ferrara, Sergio; Marrani, Alessio & Zumino, Bruno
Object Type: Article
System: The UNT Digital Library