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Diffractive W and Z Production at the Fermilab Tevatron (open access)

Diffractive W and Z Production at the Fermilab Tevatron

We report on a measurement of the fraction of events with a W or Z boson produced diffractively in {bar p}p collisions at {radical}s = 1.96 TeV, using data from 0.6 fb{sup -1} of integrated luminosity collected with the CDF II detector equipped with a Roman-pot spectrometer that detects the {bar p} from {bar p} + p {yields} {bar p}+[X+W/Z]. We find that (0.97 {+-} 0.11)% of Ws and (0.85 {+-} 0.22)% of Zs are produced diffractively in a region of (anti)proton fractional momentum loss {zeta} of 0.03 < {zeta} < 0.10 and 4-momentum transferred squared t of -1 < t < 0 (GeV/c){sup 2}. We also report on searches for W and Z production in double Pomeron exchange, p+{bar p} {yields} p+[X+W/z]+{bar p}, and on exclusive Z production, {bar p}p {yields} {bar p}+Z+p. No signal is seen above background for these processes, and comparisons are made with expectations.
Date: July 1, 2010
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
System: The UNT Digital Library
Measurement of the $t\bar{t}$ Production Cross Section with an in situ Calibration of $b$-jet Identification Efficiency (open access)

Measurement of the $t\bar{t}$ Production Cross Section with an in situ Calibration of $b$-jet Identification Efficiency

A measurement of the top-quark pair-production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using data corresponding to an integrated luminosity of 1.12 fb{sup -1} collected with the Collider Detector at Fermilab is presented. Decays of top-quark pairs into the final states e{nu} + jets and {mu}{nu} + jets are selected, and the cross section and the b-jet identification efficiency are determined using a new measurement technique which requires that the measured cross sections with exactly one and multiple identified b-quarks from the top-quark decays agree. Assuming a top-quark mass of 175 GeV/c{sup 2}, a cross section of 8.5 {+-} 0.6(stat.) {+-} 0.7(syst.) pb is measured.
Date: July 1, 2010
Creator: Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
System: The UNT Digital Library
Search for sneutrino production in $e\mu$ final states in 5.3 fb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt(s) =1.96$ TeV (open access)

Search for sneutrino production in $e\mu$ final states in 5.3 fb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt(s) =1.96$ TeV

We report the results of a search for R parity violating (RPV) interactions leading to the production of supersymmetric sneutrinos decaying into e{mu} final states using 5.3 fb{sup -1} of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Having observed no evidence for production of e{mu} resonances, we set direct bounds on the RPV couplings {lambda}{prime}{sub 311} and {lambda}{sub 312} as a function of sneutrino mass.
Date: July 1, 2010
Creator: Abazov, Victor Mukhamedovich; /Dubna, JINR; Abbott, Braden Keim; U., /Oklahoma; Abolins, Maris A.; U., /Michigan State et al.
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
A Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector (open access)

A Search for Lorentz Invariance and CPT Violation with the MINOS Far Detector

We searched for a sidereal modulation in the MINOS far detector neutrino rate. Such a signal would be a consequence of Lorentz and CPT violation as described by the Standard-Model Extension framework. It also would be the first detection of a perturbative effect to conventional neutrino mass oscillations. We found no evidence for this sidereal signature and the upper limits placed on the magnitudes of the Lorentz and CPT violating coefficients describing the theory are an improvement by factors of 20-510 over the current best limits found using the MINOS near detector.
Date: July 1, 2010
Creator: Adamson, P.; Auty, D. J.; Ayres, D. S.; Backhouse, C.; Barr, G.; Barrett, W. L. et al.
System: The UNT Digital Library
Structure and Electronic Properties of Cerium Orthophosphate: Theory and Experiment (open access)

Structure and Electronic Properties of Cerium Orthophosphate: Theory and Experiment

Structural and electronic properties of cerium orthophosphate (CePO{sub 4}) are calculated using density functional theory (DFT) with the local spin-density approximation (LSDA+U), with and without gradient corrections (GGA-(PBE)+U), and compared to X-ray diffraction and photoemission spectroscopy measurements. The density of states is found to change significantly as the Hubbard parameter U, which is applied to the Ce 4f states, is varied from 0 to 5 eV. The calculated structural properties are in good agreement with experiment and do not change significantly with U. Choosing U = 3 eV for LDSA provides the best agreement between the calculated density of states and the experimental photoemission spectra.
Date: July 27, 2010
Creator: Adelstein, Nicole; Mun, B. Simon; Ray, Hannah; Ross Jr, Phillip; Neaton, Jeffrey & De Jonghe, Lutgard
System: The UNT Digital Library
The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer (open access)

The climate of HD 189733b from fourteen transits and eclipses measured by Spitzer

We present observations of six transits and six eclipses of the transiting planet system HD 189733 taken with the Spitzer Space Telescope IRAC camera at 8 microns, as well as a re-analysis of previously published data. We use several novel techniques in our data analysis, the most important of which is a new correction for the detector 'ramp' variation with a double-exponential function which performs better and is a better physical model for this detector variation. Our main scientific findings are: (1) an upper limit on the variability of the day-side planet flux of 2.7% (68% confidence); (2) the most precise set of transit times measured for a transiting planet, with an average accuracy of 3 seconds; (3) a lack of transit-timing variations, excluding the presence of second planets in this system above 20% of the mass of Mars in low-order mean-motion resonance at 95% confidence; (4) a confirmation of the planet's phase variation, finding the night side is 64% as bright as the day side, as well as an upper limit on the night-side variability of 17% (68% confidence); (5) a better correction for stellar variability at 8 micron causing the phase function to peak 3.5 hours before secondary …
Date: July 1, 2010
Creator: Agol, E.; /Washington U., Seattle, Astron. Dept. /Santa Barbara, KITP /UC, Santa Barbara; Cowan, Nicolas B.; /Washington U., Seattle, Astron. Dept.; Knutson, Heather A.; /UC, Berkeley, Astron. Dept. et al.
System: The UNT Digital Library
Measurement of the Neutrino Neutral-Current Elastic Differential Cross Section on Mineral Oil at E sub nu ~ 1 GeV (open access)

Measurement of the Neutrino Neutral-Current Elastic Differential Cross Section on Mineral Oil at E sub nu ~ 1 GeV

We report a measurement of the flux-averaged neutral-current elastic differential cross section for neutrinos scattering on mineral oil (CH{sub 2}) as a function of four-momentum transferred squared, Q{sup 2}. It is obtained by measuring the kinematics of recoiling nucleons with kinetic energy greater than 50 MeV which are readily detected in MiniBooNE. This differential cross-section distribution is fit with fixed nucleon form factors apart from an axial mass, M{sub A}, that provides a best fit for M{sub A} = 1.39 {+-} 0.11 GeV. Using the data from the charged-current neutrino interaction sample, a ratio of neutral-current to charged-current quasi-elastic cross sections as a function of Q{sup 2} has been measured. Additionally, single protons with kinetic energies above 350 MeV can be distinguished from neutrons and multiple nucleon events. Using this marker, the strange quark contribution to the neutral-current axial vector form factor at Q{sup 2} = 0, {Delta}s, is found to be {Delta}s = 0.08{+-} 0.26.
Date: July 1, 2010
Creator: Aguilar-Arevalo, A. A.; Anderson, C. E.; Bazarko, A. O.; Brice, S. J.; Brown, B. C.; Bugel, L. et al.
System: The UNT Digital Library
MHD Simulations of Core Collapse Supernovae with Cosmos++ (open access)

MHD Simulations of Core Collapse Supernovae with Cosmos++

None
Date: July 8, 2010
Creator: Akiyama, S & Salmonson, J
System: The UNT Digital Library
Advanced Compton scattering light source R&D at LLNL (open access)

Advanced Compton scattering light source R&D at LLNL

None
Date: July 30, 2010
Creator: Albert, F.; Anderson, S. G.; Anderson, G.; Bayramian, A.; Betts, S. M.; Chu, T. S. et al.
System: The UNT Digital Library
Air Shipment of Highly Enriched Uranium Spent Nuclear Fuel from Romania (open access)

Air Shipment of Highly Enriched Uranium Spent Nuclear Fuel from Romania

Romania safely air shipped 23.7 kilograms of Russian origin highly enriched uranium (HEU) spent nuclear fuel from the VVR S research reactor at Magurele, Romania, to the Russian Federation in June 2009. This was the world’s first air shipment of spent nuclear fuel transported in a Type B(U) cask under existing international laws without special exceptions for the air transport licenses. This shipment was coordinated by the Russian Research Reactor Fuel Return Program (RRRFR), part of the U.S. Department of Energy Global Threat Reduction Initiative (GTRI), in cooperation with the Romania National Commission for Nuclear Activities Control (CNCAN), the Horia Hulubei National Institute of Physics and Nuclear Engineering (IFIN-HH), and the Russian Federation State Corporation Rosatom. The shipment was transported by truck to and from the respective commercial airports in Romania and the Russian Federation and stored at a secure nuclear facility in Russia where it will be converted into low enriched uranium. With this shipment, Romania became the 3rd country under the RRRFR program and the 14th country under the GTRI program to remove all HEU. This paper describes the work, equipment, and approvals that were required to complete this spent fuel air shipment.
Date: July 1, 2010
Creator: Allen, K. J.; Bolshinsky, I.; Biro, L. L.; Budu, M. E.; Zamfir, N. V. & Dragusin, M.
System: The UNT Digital Library
IDENTIFYING IMPURITIES IN SURPLUS NON PIT PLUTONIUM FEEDS FOR MOX OR ALTERNATIVE DISPOSITION (open access)

IDENTIFYING IMPURITIES IN SURPLUS NON PIT PLUTONIUM FEEDS FOR MOX OR ALTERNATIVE DISPOSITION

This report provides a technical basis for estimating the level of corrosion products in materials stored in DOE-STD-3013 containers based on extrapolating available chemical sample results. The primary focus is to estimate the levels of nickel, iron, and chromium impurities in plutonium-bearing materials identified for disposition in the United States Mixed Oxide fuel process.
Date: July 14, 2010
Creator: Allender, J & Moore, E
System: The UNT Digital Library
NREL GHP [Geothermal Heat Pump] Showcase: GHP Installation and Intensive in situ and Performance Monitoring at NREL's Solar Radiation and Research Laboratory; Preprint (open access)

NREL GHP [Geothermal Heat Pump] Showcase: GHP Installation and Intensive in situ and Performance Monitoring at NREL's Solar Radiation and Research Laboratory; Preprint

This document provides an overview of the geothermal heat pump (GHP) showcase at NREL and how it will help the SRRL site move forward with the goal of being a model of sustainability within the NREL campus, providing an effective demonstration of GHP systems and needed space conditioning for laboratory expansion.
Date: July 1, 2010
Creator: Anderson, E. R.
System: The UNT Digital Library
Cyber Threats to Nuclear Infrastructures (open access)

Cyber Threats to Nuclear Infrastructures

Nuclear facility personnel expend considerable efforts to ensure that their facilities can maintain continuity of operations against both natural and man-made threats. Historically, most attention has been placed on physical security. Recently however, the threat of cyber-related attacks has become a recognized and growing world-wide concern. Much attention has focused on the vulnerability of the electric grid and chemical industries to cyber attacks, in part, because of their use of Supervisory Control and Data Acquisition (SCADA) systems. Lessons learned from work in these sectors indicate that the cyber threat may extend to other critical infrastructures including sites where nuclear and radiological materials are now stored. In this context, this white paper presents a hypothetical scenario by which a determined adversary launches a cyber attack that compromises the physical protection system and results in a reduced security posture at such a site. The compromised security posture might then be malevolently exploited in a variety of ways. The authors conclude that the cyber threat should be carefully considered for all nuclear infrastructures.
Date: July 1, 2010
Creator: Anderson, Robert S.; Moskowitz, Paul; Schanfein, Mark; Bjornard, Trond & Michel, Curtis St.
System: The UNT Digital Library
Further Developments on the Geothermal System Scoping Model: Preprint (open access)

Further Developments on the Geothermal System Scoping Model: Preprint

This paper discusses further developments and refinements for the uses of the Geothermal System Scoping Model in an effort to provide a means for performing a variety of trade-off analyses of surface and subsurface parameters, sensitivity analyses, and other systems engineering studies in order to better inform R&D direction and investment for the development of geothermal power into a major contributor to the U.S. energy supply.
Date: July 1, 2010
Creator: Antkowiak, M.; Sargent, R. & Geiger, J. W.
System: The UNT Digital Library
Beyond the Death of Linear Response: 1/f Optimal Information Transport (open access)

Beyond the Death of Linear Response: 1/f Optimal Information Transport

Article discussing research on linear response and 1/f optimal information transport.
Date: July 21, 2010
Creator: Aquino, Gerardo; Bologna, Mauro; Grigolini, Paolo & West, Bruce J.
System: The UNT Digital Library
Ultrafast observation of shocked states in a precompressed material (open access)

Ultrafast observation of shocked states in a precompressed material

None
Date: July 8, 2010
Creator: Armstrong, M R; Crowhurst, J C; Bastea, S & Zaug, J M
System: The UNT Digital Library
Detection of Hohlraum Target Position for Laser Fusion Experiments (open access)

Detection of Hohlraum Target Position for Laser Fusion Experiments

None
Date: July 6, 2010
Creator: Awwal, A. A.
System: The UNT Digital Library
Shack-Hartmann Wavefront Sensing Performance Evaluation for Active Correction of the Large Synoptic Survey Telescope (LSST) (open access)

Shack-Hartmann Wavefront Sensing Performance Evaluation for Active Correction of the Large Synoptic Survey Telescope (LSST)

None
Date: July 21, 2010
Creator: Baker, K L & Seppala, L
System: The UNT Digital Library
2010 Thin Film & Small Scale Mechanical Behavior Gordon Research Conference (open access)

2010 Thin Film & Small Scale Mechanical Behavior Gordon Research Conference

Over the past decades, it has been well established that the mechanical behavior of materials changes when they are confined geometrically at least in one dimension to small scale. It is the aim of the 2010 Gordon Conference on 'Thin Film and Small Scale Mechanical Behavior' to discuss cutting-edge research on elastic, plastic and time-dependent deformation as well as degradation mechanisms like fracture, fatigue and wear at small scales. As in the past, the conference will benefit from contributions from fundamental studies of physical mechanisms linked to material science and engineering reaching towards application in modern applications ranging from optical and microelectronic devices and nano- or micro-electrical mechanical systems to devices for energy production and storage. The conference will feature entirely new testing methodologies and in situ measurements as well as recent progress in atomistic and micromechanical modeling. Particularly, emerging topics in the area of energy conversion and storage, such as material for batteries will be highlighted. The study of small-scale mechanical phenomena in systems related to energy production, conversion or storage offer an enticing opportunity to materials scientists, who can provide new insight and investigate these phenomena with methods that have not previously been exploited.
Date: July 30, 2010
Creator: Balk, Dr. Thomas
System: The UNT Digital Library
Two-Photon Interactions with Nuclear Breakup in Relativistic Heavy Ion Collisions (open access)

Two-Photon Interactions with Nuclear Breakup in Relativistic Heavy Ion Collisions

Highly charged relativistic heavy ions have high cross-sections for two-photon interactions. The photon flux is high enough that two-photon interactions may be accompanied by additional photonuclear interactions. Except for the shared impact parameter, these interactions are independent. Additional interactions like mutual Coulomb excitation are of experimental interest, since the neutrons from the nuclear dissociation provide a simple, relatively unbiased trigger. We calculate the cross sections, rapidity, mass and transverse momentum (p{sub T}) distributions for exclusive {gamma}{gamma} production of mesons and lepton pairs, and for {gamma}{gamma} reactions accompanied by mutual Coulomb dissociation. The cross-sections for {gamma}{gamma} interactions accompanied by multiple neutron emission (XnXn) and single neutron emission (1n1n) are about 1/10 and 1/100 of that for the unaccompanied {gamma}{gamma} interactions. We discuss the accuracy with which these cross-sections may be calculated. The typical p{sub T} of {gamma}{gamma} final states is several times smaller than for comparable coherent photonuclear interactions, so p{sub T} may be an effective tool for separating the two classes of interactions.
Date: July 7, 2010
Creator: Baltz, Anthony J.; Gorbunov, Yuri; R Klein, Spencer & Nystrand, Joakim
System: The UNT Digital Library
Threshold Studies of the Microwave Instability in Electron Storage Rings (open access)

Threshold Studies of the Microwave Instability in Electron Storage Rings

We use a Vlasov-Fokker-Planck program and a linearized Vlasov solver to study the microwave instability threshold of impedance models: (1) a Q = 1 resonator and (2) shielded coherent synchrotron radiation (CSR), and find the results of the two programs agree well. For shielded CSR we show that only two dimensionless parameters, the shielding parameter {Pi} and the strength parameter S{sub csr}, are needed to describe the system. We further show that there is a strong instability associated with CSR, and that the threshold, to good approximation, is given by (S{sub csr})th = 0.5 + 0.12{Pi}. In particular, this means that shielding has little effect in stabilizing the beam for {Pi} {approx}< 2; for larger {Pi} it is effective, with threshold current depending on shielding aperture as h{sup -3/2}. We, in addition, find another instability in the vicinity of {Pi} = 0.7 with a lower threshold, (S{sub csr}){sub th} {approx} 0.2. We find that the threshold to this instability depends strongly on damping time, (S{sub csr}){sub th} {approx} {tau}{sub p}{sup -1/2}, and that the tune spread at threshold is small - both hallmarks of a weak instability.
Date: July 30, 2010
Creator: Bane, K. L. F.; Cai, Y. & Stupakov, G.
System: The UNT Digital Library
Developmental long trace profiler using optimally aligned mirror based pentaprism (open access)

Developmental long trace profiler using optimally aligned mirror based pentaprism

A low-budget surface slope measuring instrument, the Developmental Long Trace Profiler (DLTP), was recently brought into operation at the Advanced Light Source Optical Metrology Laboratory [Nucl. Instr. and Meth. A 616, 212-223 (2010)]. The instrument is based on a precisely calibrated autocollimator and a movable pentaprism. The capability of the DLTP to achieve sub-microradian surface slope metrology has been verified via cross-comparison measurements with other high-performance slope measuring instruments when measuring the same high-quality test optics. In the present work, a further improvement of the DLTP is achieved by replacing the existing bulk pentaprism with a specially designed mirror based pentaprism. A mirror based pentaprism offers the possibility to eliminate systematic errors introduced by inhomogeneity of the optical material and fabrication imperfections of a bulk pentaprism. We provide the details of the mirror based pentaprism design and describe an original experimental procedure for precision mutual alignment of the mirrors. The algorithm of the alignment procedure and its efficiency are verified with rigorous ray tracing simulations. Results of measurements of a spherically curved test mirror and a flat test mirror using the original bulk pentaprism are compared with measurements using the new mirror based pentaprism, demonstrating the improved performance.
Date: July 21, 2010
Creator: Barber, Samuel K; Morrison, Gregory Y.; Yashchuk, Valeriy V.; Gubarev, Mikhail V.; Geckeler, Ralf D.; Buchheim, Jana et al.
System: The UNT Digital Library
2010 GORDON RESEARCH CONFERENCE ON MITOCHONDRIA & CHLOROPLASTS, LUCCA, ITALY, JULY 11-16, 2010 (open access)

2010 GORDON RESEARCH CONFERENCE ON MITOCHONDRIA & CHLOROPLASTS, LUCCA, ITALY, JULY 11-16, 2010

The 2010 GRC on Mitochondria & Chloroplasts will assemble an international group of molecular, structural and cellular biologists, biochemists and geneticists investigating a broad spectrum of fundamental problems related to the biology of these organelles in animal, plant and fungal cells. This field has witnessed an extraordinary expansion in recent years, fueled by the discovery of the role of mitochondria in human disease and ageing, and of the synergy of chloroplasts and mitochondria in energetic output, the identification of novel factors involved in organelle division, movement, signaling and acclimation to changing environmental conditions, and by the powerful tools of organelle proteomics. The 2010 GRC will highlight advances in the elucidation of molecular mechanisms of organelle biogenesis including regulation of genome structure, evolution and expression, organellar protein import, assembly and turnover of respiratory and photosynthetic complexes, bidirectional signaling between organelles and nucleus, organelle morphology and dynamics, and the integration of cellular metabolism. We will also explore progress in mechanisms of disease and ageing/ senescence in animals and plants. The organellar field has forged new fronts toward a global and comprehensive understanding of mitochondrial and chloroplast biology at the molecular level. Many of the molecules under study in model organisms are responsible …
Date: July 16, 2010
Creator: Barkan, Alice
System: The UNT Digital Library