An Examination of Temporal Trends in Electricity Reliability Based on Reports from U.S. Electric Utilities (open access)

An Examination of Temporal Trends in Electricity Reliability Based on Reports from U.S. Electric Utilities

Since the 1960s, the U.S. electric power system has experienced a major blackout about once every 10 years. Each has been a vivid reminder of the importance society places on the continuous availability of electricity and has led to calls for changes to enhance reliability. At the root of these calls are judgments about what reliability is worth and how much should be paid to ensure it. In principle, comprehensive information on the actual reliability of the electric power system and on how proposed changes would affect reliability ought to help inform these judgments. Yet, comprehensive, national-scale information on the reliability of the U.S. electric power system is lacking. This report helps to address this information gap by assessing trends in U.S. electricity reliability based on information reported by electric utilities on power interruptions experienced by their customers. Our research augments prior investigations, which focused only on power interruptions originating in the bulk power system, by considering interruptions originating both from the bulk power system and from within local distribution systems. Our research also accounts for differences among utility reliability reporting practices by employing statistical techniques that remove the influence of these differences on the trends that we identify. The …
Date: January 6, 2012
Creator: Eto, Joseph H.; LaCommare, Kristina Hamachi; Larsen, Peter; Todd, Annika & Fisher, Emily
Object Type: Report
System: The UNT Digital Library
Exploration of Optimization Options for Increasing Performance of a GPU Implementation of a Three-dimensional Bilateral Filter (open access)

Exploration of Optimization Options for Increasing Performance of a GPU Implementation of a Three-dimensional Bilateral Filter

This report explores using GPUs as a platform for performing high performance medical image data processing, specifically smoothing using a 3D bilateral filter, which performs anisotropic, edge-preserving smoothing. The algorithm consists of a running a specialized 3D convolution kernel over a source volume to produce an output volume. Overall, our objective is to understand what algorithmic design choices and configuration options lead to optimal performance of this algorithm on the GPU. We explore the performance impact of using different memory access patterns, of using different types of device/on-chip memories, of using strictly aligned and unaligned memory, and of varying the size/shape of thread blocks. Our results reveal optimal configuration parameters for our algorithm when executed sample 3D medical data set, and show performance gains ranging from 30x to over 200x as compared to a single-threaded CPU implementation.
Date: January 6, 2012
Creator: Bethel, E. Wes & Bethel, E. Wes
Object Type: Report
System: The UNT Digital Library
Gamma-ray and Radio Properties of Six Pulsars Detected by the Fermi Large Area Telescope (open access)

Gamma-ray and Radio Properties of Six Pulsars Detected by the Fermi Large Area Telescope

None
Date: January 6, 2012
Creator: Weltevrede, P.; Abdo, A. A.; Ackermann, M.; Ajello, M.; Axelsson, M.; Baldini, L. et al.
Object Type: Article
System: The UNT Digital Library
INVESTIGATION OF PLUTONIUM AND URANIUM UPTAKE INTO MCU SOLVENT AND NEXT GENERATION SOLVENT (open access)

INVESTIGATION OF PLUTONIUM AND URANIUM UPTAKE INTO MCU SOLVENT AND NEXT GENERATION SOLVENT

At the request of the Savannah River Remediation (SRR) customer, the Savannah River National Laboratory (SRNL) examined the plutonium (Pu) and uranium (U) uptake into the Next Generation Solvent (NGS) that will be used at the Salt Waste Processing Facility (SWPF). SRNL examined archived samples of solvent used in Extraction-Scrub-Strip (ESS) tests, as well as samples from new tests designed explicitly to examine the Pu and U uptake. Direct radiocounting for Pu and U provided the best results. Using the radiocounting results, we found that in all cases there were <3.41E-12 g Pu/g of NGS and <1.17E-05 g U/g of NGS in multiple samples, even after extended contact times and high aqueous:organic volume phase ratios. These values are conservative as they do not allow for release or removal of the actinides by scrub, strip, or solvent wash processes. The values do not account for extended use or any increase that may occur due to radiolytic damage of the solvent.
Date: January 6, 2012
Creator: Peters, T. & Fink, S.
Object Type: Report
System: The UNT Digital Library
A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC (open access)

A Proof-of-Principle Echo-enabled Harmonic Generation Free Electron Laser Experiment at SLAC

With the advent of X-ray Free Electron Lasers (FELs), new methods have been developed to extend capabilities at short wavelengths beyond Self-Amplified Spontaneous Emission (SASE). In particular, seeding of a FEL allows for temporal control of the radiation pulse and increases the peak brightness by orders of magnitude. Most recently, Gennady Stupakov and colleagues at SLAC proposed a new technique: Echo-Enabled Harmonic Generation (EEHG). Here a laser microbunches the beam in an undulator and the beam is sheared in a chicane. This process is repeated with a second laser, undulator and chicane. The interplay between these allows a seeding of the X-ray laser up to the 100th harmonic of the first laser. After introducing the physics of FELs and the EEHG seeding technique, we describe contributions to the experimental effort. We will present detailed studies of the experiment including the choice of parameters and their optimization, the emittance effect, spontaneous emission in the undulators, the second laser phase effect, and measurements of the jitter between RF stations. Finally, the status and preliminary results of the Echo-7 experiment will be outlined.
Date: January 6, 2012
Creator: Pernet, Pierre-Louis
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Final Progress Report (open access)

Final Progress Report

The BIOMOL grant was for 'Local System Support for PDB Biological Unit Search and Display' to augment Rasmol's [Bernstein 2000] [Sayle, Milner-White 1995] existing macromolecular display functions with new capabilities by taking advantage of recent increases in local computing power in order to move functionality that is now scattered among various local and remote systems into one local package. Work included new algorithms for molecular surface display, an extended format for Protein Data Bank Entries, work on issues relating to the integration of multiple diffraction images formats.
Date: February 6, 2012
Creator: Bernstein, Herbert J.
Object Type: Text
System: The UNT Digital Library
Biomass Gas Cleanup Using a Therminator (open access)

Biomass Gas Cleanup Using a Therminator

The objective of the project is to develop and demonstrate a novel fluidized-bed process module called a “Therminator” to simultaneously destroy and/or remove tar, NH3 and H2S from raw syngas produced by a fluidized-bed biomass gasifier. The raw syngas contains as much as 10 g/m3 of tar, 4,000 ppmv of NH3 and 100 ppmv of H2S. The goal of the Therminator module would be to use promising regenerable catalysts developed for removing tar, ammonia, and H2S down to low levels (around 10 ppm). Tars are cracked to a non-condensable gas and coke that would deposit on the acid catalyst. We will deposit coke, much like a fluid catalytic cracker (FCC) in a petroleum refinery. The deposited coke fouls the catalyst, much like FCC, but the coke would be burned off in the regenerator and the regenerated catalyst would be returned to the cracker. The rapid circulation between the cracker and regenerator would ensure the availability of the required amount of regenerated catalyst to accomplish our goal. Also, by removing sulfur down to less than 10 ppmv, NH3 decomposition would also be possible in the cracker at 600-700°C. In the cracker, tar decomposes and lays down coke on the acid sites …
Date: March 6, 2012
Creator: Dayton, David C.; Kataria, Atish & Gupta, Rabhubir
Object Type: Report
System: The UNT Digital Library
Calculation of Kinetics Parameters for the NBSR (open access)

Calculation of Kinetics Parameters for the NBSR

The delayed neutron fraction and prompt neutron lifetime have been calculated at different times in the fuel cycle for the NBSR when fueled with both high-enriched uranium (HEU) and low-enriched uranium (LEU) fuel. The best-estimate values for both the delayed neutron fraction and the prompt neutron lifetime are the result of calculations using MCNP5-1.60 with the most recent ENDFB-VII evaluations. The best-estimate values for the total delayed neutron fraction from fission products are 0.00665 and 0.00661 for the HEU fueled core at startup and end-of-cycle, respectively. For the LEU fuel the best estimate values are 0.00650 and 0.00648 at startup and end-of-cycle, respectively. The present recommendations for the delayed neutron fractions from fission products are smaller than the value reported previously of 0.00726 for the HEU fuel. The best-estimate values for the contribution from photoneutrons will remain as 0.000316, independent of the fuel or time in the cycle.The values of the prompt neutron lifetime as calculated with MCNP5-1.60 are compared to values calculated with two other independent methods and the results are in reasonable agreement with each other. The recommended, conservative values of the neutron lifetime for the HEU fuel are 650 {micro}s and 750 {micro}s for the startup and …
Date: March 6, 2012
Creator: L., Hanson A. & D., Diamond
Object Type: Report
System: The UNT Digital Library
Data Summary Report for Hanford Site Coal Ash Characterization (open access)

Data Summary Report for Hanford Site Coal Ash Characterization

The purpose of this report is to present data and findings from sampling and analysis of five distinct areas of coal ash within the Hanford Site River Corridor
Date: March 6, 2012
Creator: Sulloway, H. M.
Object Type: Report
System: The UNT Digital Library
A High Resolution Monolithic Crystal, DOI, MR Compatible, PET Detector (open access)

A High Resolution Monolithic Crystal, DOI, MR Compatible, PET Detector

The principle objective of this proposal is to develop a positron emission tomography (PET) detector with depth-of-interaction (DOI) positioning capability that will achieve state of the art spatial resolution and sensitivity performance for small animal PET imaging. When arranged in a ring or box detector geometry, the proposed detector module will support <1 mm3 image resolution and >15% absolute detection efficiency. The detector will also be compatible with operation in a MR scanner to support simultaneous multi-modality imaging. The detector design will utilize a thick, monolithic crystal scintillator readout by a two-dimensional array of silicon photomultiplier (SiPM) devices using a novel sensor on the entrance surface (SES) design. Our hypothesis is that our single-ended readout SES design will provide an effective DOI positioning performance equivalent to more expensive dual-ended readout techniques and at a significantly lower cost. Our monolithic crystal design will also lead to a significantly lower cost system. It is our goal to design a detector with state of the art performance but at a price point that is affordable so the technology can be disseminated to many laboratories. A second hypothesis is that using SiPM arrays, the detector will be able to operate in a MR scanner …
Date: March 6, 2012
Creator: Miyaoka, Robert S
Object Type: Report
System: The UNT Digital Library
Ka-Band ARM Zenith Radar (KAZR) Instrument Handbook (open access)

Ka-Band ARM Zenith Radar (KAZR) Instrument Handbook

The Ka-band ARM zenith radar (KAZR) is a zenith-pointing Doppler cloud radar operating at approximately 35 GHz. The KAZR is an evolutionary follow-on radar to ARM's widely successful millimeter-wavelength cloud radar (MMCR). The main purpose of the KAZR is to provide vertical profiles of clouds by measuring the first three Doppler moments: reflectivity, radial Doppler velocity, and spectra width. At the sites where the dual-polarization measurements are made, the Doppler moments for the cross-polarization channel are also available. In addition to the moments, velocity spectra are also continuously recorded for each range gate.
Date: March 6, 2012
Creator: Widener, K.; Bharadwaj, N. & Johnson, K.
Object Type: Report
System: The UNT Digital Library
LITERATURE REVIEW OF PUO2 CALCINATION TIME AND TEMPERATURE DATA FOR SPECIFIC SURFACE AREA (open access)

LITERATURE REVIEW OF PUO2 CALCINATION TIME AND TEMPERATURE DATA FOR SPECIFIC SURFACE AREA

The literature has been reviewed in December 2011 for calcination data of plutonium oxide (PuO{sub 2}) from plutonium oxalate Pu(C{sub 2}O{sub 4}){sub 2} precipitation with respect to the PuO{sub 2} specific surface area (SSA). A summary of the literature is presented for what are believed to be the dominant factors influencing SSA, the calcination temperature and time. The PuO{sub 2} from Pu(C{sub 2}O{sub 4}){sub 2} calcination data from this review has been regressed to better understand the influence of calcination temperature and time on SSA. Based on this literature review data set, calcination temperature has a bigger impact on SSA versus time. However, there is still some variance in this data set that may be reflecting differences in the plutonium oxalate preparation or different calcination techniques. It is evident from this review that additional calcination temperature and time data for PuO{sub 2} from Pu(C{sub 2}O{sub 4}){sub 2} needs to be collected and evaluated to better define the relationship. The existing data set has a lot of calcination times that are about 2 hours and therefore may be underestimating the impact of heating time on SSA. SRNL recommends that more calcination temperature and time data for PuO{sub 2} from Pu(C{sub 2}O{sub …
Date: March 6, 2012
Creator: Daniel, G.
Object Type: Report
System: The UNT Digital Library
Management Principles for Nonproliferation Organizations (open access)

Management Principles for Nonproliferation Organizations

This paper identifies business models and six management principles that can be applied by a nonproliferation organization to maximize the value and effectiveness of its products. The organizations responsible for reducing the nuclear proliferation threat have experienced a substantial growth in responsibility and visibility since the September 11 attacks. Since then, the international community has witnessed revelations of clandestine nuclear facilities, nuclear black markets, periodic nuclear tests, and a resurgence of interest by countries worldwide in developing nuclear capabilities. The security environment will likely continue to evolve in unexpected ways since most of the proliferation threats with which the world will be forced to contend remain unforeseen. To better prepare for and respond to this evolving security environment, many nonproliferation organizations are interested in finding new or better ways to increase the effectiveness and efficiency of their operations. Of course, all organizations, whether they are market driven or non-profit, must operate effectively and efficiently if they are to succeed. Indeed, as this study demonstrates, many of the management principles that this study recommends can help all organizations succeed. However, this study pays particular attention to nonproliferation organizations because of the mission they are responsible for fulfilling. Nonproliferation organizations, including nonproliferation …
Date: March 6, 2012
Creator: Frazar, Sarah L. & Hund, Gretchen
Object Type: Report
System: The UNT Digital Library
Parameterization of the Extinction Coefficient in Ice and Mixed-Phase Arctic Clouds during the ISDAC Field Campaign (open access)

Parameterization of the Extinction Coefficient in Ice and Mixed-Phase Arctic Clouds during the ISDAC Field Campaign

This report documents the history of attempts to directly measure cloud extinction, the current measurement device known as the Cloud Extinction Probe (CEP), specific problems with direct measurement of extinction coefficient, and the attempts made here to address these problems. Extinction coefficient is one of the fundamental microphysical parameters characterizing bulk properties of clouds. Knowledge of extinction coefficient is of crucial importance for radiative transfer calculations in weather prediction and climate models given that Earth's radiation budget (ERB) is modulated much by clouds. In order for a large-scale model to properly account for ERB and perturbations to it, it must ultimately be able to simulate cloud extinction coefficient well. In turn this requires adequate and simultaneous simulation of profiles of cloud water content and particle habit and size. Similarly, remote inference of cloud properties requires assumptions to be made about cloud phase and associated single-scattering properties, of which extinction coefficient is crucial. Hence, extinction coefficient plays an important role in both application and validation of methods for remote inference of cloud properties from data obtained from both satellite and surface sensors (e.g., Barker et al. 2008). While estimation of extinction coefficient within large-scale models is relatively straightforward for pure water …
Date: March 6, 2012
Creator: Korolev, A; Shashkov, A & Barker, H
Object Type: Report
System: The UNT Digital Library
Rhodium mediated bond activation: from synthesis to catalysis (open access)

Rhodium mediated bond activation: from synthesis to catalysis

Recently, our lab has developed monoanionic tridentate ligand, To{sup R}, showing the corresponding coordination chemistry and catalyst reactivity of magnesium, zirconium, zinc and iridium complexes. This thesis details synthetic chemistry, structural study and catalytic reactivity of the To{sup R}-supported rhodium compounds. Tl[To{sup R}] has been proved to be a superior ligand transfer agent for synthesizing rhodium complexes. The salt metathesis route of Tl[To{sup M}] with [Rh({mu}-Cl)(CO)]{sub 2} and [Rh({mu}- Cl)(COE)]{sub 2} gives To{sup M}Rh(CO){sub 2} (2.2) and To{sup M}RhH({eta}{sup 3}-C{sub 8}H{sub 13}) (3.1) respectively while Tl[To{sup P}] with [Rh({mu}-Cl)(CO)]{sub 2} affords To{sup P}Rh(CO){sub 2} (2.3). 2.2 reacts with both strong and weak electrophiles, resulting in the oxazoline N-attacked and the metal center-attacked compounds correspondingly. Using one of the metal center-attacked electrophiles, 2.3 was demonstrated to give high diastereoselectivity. Parallel to COE allylic C-H activation complex 3.1, the propene and allylbenzene allylic C-H activation products have also been synthesized. The subsequent functionalization attempts have been examined by treating with Brønsted acids, Lewis acids, electrophiles, nucleophiles, 1,3-dipolar reagents and reagents containing multiple bonds able to be inserted. Various related complexes have been obtained under these conditions, in which one of the azide insertion compounds reductively eliminates to give an allylic functionalization product …
Date: March 6, 2012
Creator: Ho, Hung-An
Object Type: Thesis or Dissertation
System: The UNT Digital Library
SRNL PHASE 1 ASSESSMENT OF THE WTP WASTE QUALIFICATION PROGRAM (open access)

SRNL PHASE 1 ASSESSMENT OF THE WTP WASTE QUALIFICATION PROGRAM

The Hanford Tank Waste Treatment and Immobilization Plant (WTP) Project is currently transitioning its emphasis from an engineering design and construction phase toward facility completion, start-up and commissioning. With this transition, the WTP Project has initiated more detailed assessments of the requirements that must be met during the actual processing of the Hanford Site tank waste. One particular area of interest is the waste qualification program. In general, the waste qualification program involves testing and analysis to demonstrate compliance with waste acceptance criteria, determine waste processability, and demonstrate laboratory-scale unit operations to support WTP operations. The testing and analysis are driven by data quality objectives (DQO) requirements necessary for meeting waste acceptance criteria for transfer of high-level wastes from the tank farms to the WTP, and for ensuring waste processability including proper glass formulations during processing within the WTP complex. Given the successful implementation of similar waste qualification efforts at the Savannah River Site (SRS) which were based on critical technical support and guidance from the Savannah River National Laboratory (SRNL), WTP requested subject matter experts (SMEs) from SRNL to support a technology exchange with respect to waste qualification programs in which a critical review of the WTP program could …
Date: March 6, 2012
Creator: Peeler, D.; Hansen, E.; Herman, C.; Marra, S. & Wilmarth, B.
Object Type: Report
System: The UNT Digital Library
Summary Report of the Consultants Meeting on Further Development of EXFOR (open access)

Summary Report of the Consultants Meeting on Further Development of EXFOR

N/A
Date: March 6, 2012
Creator: D., Brown
Object Type: Report
System: The UNT Digital Library
Charmless Hadronic B Decays into Vector, Axial Vector and Tensor Final States at BaBar (open access)

Charmless Hadronic B Decays into Vector, Axial Vector and Tensor Final States at BaBar

We present experimental measurements of branching fraction and longitudinal polarization fraction in charmless hadronic B decays into vector, axial vector and tensor final states with the final dataset of BABAR. Measurements of such kind of decays are a powerful tool both to test the Standard Model and search possible sources of new physics. In this document we present a short review of the last experimental results at BABAR concerning charmless quasi two-body decays in final states containing particles with spin 1 or spin 2 and different parities. This kind of decays has received considerable theoretical interest in the last few years and this particular attention has led to interesting experimental results at the current b-factories. In fact, the study of longitudinal polarization fraction f{sub L} in charmless B decays to vector vector (VV), vector axial-vector (VA) and axial-vector axial-vector (AA) mesons provides information on the underlying helicity structure of the decay mechanism. Naive helicity conservation arguments predict a dominant longitudinal polarization fraction f{sub L} {approx} 1 for both tree and penguin dominated decays and this pattern seems to be confirmed by tree-dominated B {yields} {rho}{rho} and B{sup +} {yields} {Omega}{rho}{sup +} decays. Other penguin dominated decays, instead, show a different …
Date: April 6, 2012
Creator: Gandini, Paolo
Object Type: Article
System: The UNT Digital Library
Emerging Energy-efficiency and CO{sub 2} Emission-reduction Technologies for Cement and Concrete Production (open access)

Emerging Energy-efficiency and CO{sub 2} Emission-reduction Technologies for Cement and Concrete Production

Globally, the cement industry accounts for approximately 5 percent of current anthropogenic carbon dioxide (CO{sub 2}) emissions. World cement demand and production are increasing significantly, leading to an increase in this industry's absolute energy use and CO{sub 2} emissions. Development of new energy-efficiency and CO{sub 2} emission-reduction technologies and their deployment in the market will be key for the cement industry's mid- and long-term climate change mitigation strategies. This report is an initial effort to compile available information on process description, energy savings, environmental and other benefits, costs, commercialization status, and references for emerging technologies to reduce the cement industry's energy use and CO{sub 2} emissions. Although studies from around the world identify a variety of sector-specific and cross-cutting energy-efficiency technologies for the cement industry that have already been commercialized, information is scarce and/or scattered regarding emerging or advanced energy-efficiency and low-carbon technologies that are not yet commercialized. This report consolidates available information on nineteen emerging technologies for the cement industry, with the goal of providing engineers, researchers, investors, cement companies, policy makers, and other interested parties with easy access to a well-structured database of information on these technologies.
Date: April 6, 2012
Creator: Hasanbeigi, Ali; Price, Lynn & Lin, Elina
Object Type: Report
System: The UNT Digital Library
Feedback Control Of An Azimuthal Oscillation In The ExB Discharge of Hall Thrusters (open access)

Feedback Control Of An Azimuthal Oscillation In The ExB Discharge of Hall Thrusters

Feedback control of a low-frequency azimuthal wave known as a "rotating spoke" in the ExB discharge of a cylindrical Hall thruster was demonstrated. The rotating spoke is an m=1 azimuthal variation in density, electron temperature, and potential that rotates at about 10% of the local E x B electron rotation speed. It causes increased electron transport across the magnetic field and is suspected to be an ionization wave. Feedback control of this wave required special consideration because, although it causes a rotating azimuthal variation in the current density to the anode, it does not show up as a signal in the total thruster discharge current. Therefore, an extra source of information was needed to track the oscillation, which was addressed by using a special anode that was split azimuthally into four segments. The current to each segment oscillates as the rotating spoke passes over it, and feedback is accomplished by resistors connected in series with each anode segment which cause the voltage on a segment to decrease in proportion to the current through that segment. The feedback resulted in the disappearance of a coherent azimuthal wave and a decrease in the time-averaged total discharge current by up to 13.2%.
Date: April 6, 2012
Creator: Martin E. Griswold, C.L. Ellison, Y. Raitses and N.J. Fisch
Object Type: Report
System: The UNT Digital Library
A General Nonlinear Fluid Model for Reacting Plasma-Neutral Mixtures (open access)

A General Nonlinear Fluid Model for Reacting Plasma-Neutral Mixtures

A generalized, computationally tractable fluid model for capturing the effects of neutral particles in plasmas is derived. The model derivation begins with Boltzmann equations for singly charged ions, electrons, and a single neutral species. Electron-impact ionization, radiative recombination, and resonant charge exchange reactions are included. Moments of the reaction collision terms are detailed. Moments of the Boltzmann equations for electron, ion, and neutral species are combined to yield a two-component plasma-neutral fluid model. Separate density, momentum, and energy equations, each including reaction transfer terms, are produced for the plasma and neutral equations. The required closures for the plasma-neutral model are discussed.
Date: April 6, 2012
Creator: Meier, E T & Shumlak, U
Object Type: Article
System: The UNT Digital Library
Hadronic Contributions to R and G-2 from Initial-State-Radiation Data (open access)

Hadronic Contributions to R and G-2 from Initial-State-Radiation Data

I review the recent efforts to improve the precision of the prediction of the anomalous moment of the muon, in particular of the hadronic contribution of the vacuum polarization, which is the contribution with the largest uncertainty. Focus is given to the recent result for e{sup +}e{sup -} {yields} {pi}{sup +}{pi}{sup -} by the BaBar collaboration, obtained using events with radiation in the initial state.
Date: April 6, 2012
Creator: Bernard, Denis, 1 & Polytechnique, /Ecole
Object Type: Article
System: The UNT Digital Library
Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves (open access)

Improved Dark Energy Constraints From ~ 100 New CfA Supernova Type Ia Light Curves

We combine the CfA3 supernovae Type Ia (SN Ia) sample with samples from the literature to calculate improved constraints on the dark energy equation of state parameter, w. The CfA3 sample is added to the Union set of Kowalski et al. to form the Constitution set and, combined with a BAO prior, produces 1 + w = 0.013{sub -0.068}{sup +0.066} (0.11 syst), consistent with the cosmological constant. The CfA3 addition makes the cosmologically useful sample of nearby SN Ia between 2.6 and 2.9 times larger than before, reducing the statistical uncertainty to the point where systematics play the largest role. We use four light-curve fitters to test for systematic differences: SALT, SALT2, MLCS2k2 (R{sub V} = 3.1), and MLCS2k2 (R{sub V} = 1.7). SALT produces high-redshift Hubble residuals with systematic trends versus color and larger scatter than MLCS2k2. MLCS2k2 overestimates the intrinsic luminosity of SN Ia with 0.7 < {Delta} < 1.2. MLCS2k2 with R{sub V} = 3.1 overestimates host-galaxy extinction while R{sub V} {approx} 1.7 does not. Our investigation is consistent with no Hubble bubble. We also find that, after light-curve correction, SN Ia in Scd/Sd/Irr hosts are intrinsically fainter than those in E/S0 hosts by 2{sigma}, suggesting that …
Date: April 6, 2012
Creator: Hicken, Malcolm; U., /Harvard-Smithsonian Ctr. Astrophys. /Harvard; Wood-Vasey, W.Michael; U., /Pittsburgh; Blondin, Stephane; Observ., /European Southern et al.
Object Type: Article
System: The UNT Digital Library
ISR Physics at BaBar (open access)

ISR Physics at BaBar

A method of measuring e{sup +}e{sup -} annihilation cross sections at low energy {radical}s < 5 GeV, using initial-state radiation, is described. Experimental data from the PEP-II B-factory at 10.6 GeV center-of-mass energy, obtained via ISR, are presented. The cross sections are measured for many processes e{sup +}e{sup -} {yields} 3{pi}, 4{pi}, 2K{pi}, 2K2{pi}, 4K, p{bar p}, {Lambda}{Lambda}, D{bar D}, ... . From the measured cross sections the parameters of known resonances are improved, the baryons form factors are derived and compared with theory predictions. New states, e.g; Y(4260) and Y(2175), for which the internal structure is not yet established, are observed.
Date: April 6, 2012
Creator: Serednyakov, S .I.
Object Type: Article
System: The UNT Digital Library