DETERMINING THE RATIO OF THE H+ YIELDS TV TO H+ YIELDS TB DECAY RATES FOR LARGE TAN BETA AT THE LARGE HADRON COLLIDER. (open access)

DETERMINING THE RATIO OF THE H+ YIELDS TV TO H+ YIELDS TB DECAY RATES FOR LARGE TAN BETA AT THE LARGE HADRON COLLIDER.

We present results on the determination of the observable ratio R = BR(H{sup +} {yields} {tau}{sup +}{nu}{sup -})/BR(H{sup +} {yields} t{bar b}) of charged Higgs boson decay rates as a discriminant quantity between Supersymmetric and non-Supersymmetric models. Simulation of measurements of this quantity through the analysis of the charged Higgs production process gb {yields} tbH{sup +} and relative backgrounds in the two above decay channels has been performed in the context of ATLAS. A {approx} 12-14% accuracy on R can be achieved for tan {beta} = 50, m{sub H{sup {+-}}} = 300-500 GeV and after an integrated luminosity of 300 fb{sup -1}. With this precision measurement, the Large Hadron Collider (LHC) can easily discriminate between models for the two above scenarios, so long as tan {beta} > 20.
Date: May 27, 2003
Creator: ASSAMAGAN,K. A. GUASCH,J. MORETTI,S. PENARANDA,S.
Object Type: Article
System: The UNT Digital Library
LSST data pipeline prototyping plans and strategy (open access)

LSST data pipeline prototyping plans and strategy

In this document we describe our approach and strategy for building the prototype for the image-stream analysis data pipeline. We start by describing the main research areas upon which we will be focusing; we then describe our plans on how to carry these research ideas to implement the data pipeline.
Date: May 27, 2004
Creator: Abdulla, G. M.; Brase, J.; Cook, K. & Miller, M.
Object Type: Report
System: The UNT Digital Library
Bifurcations and Patterns in Nonlinear Dissipative Systems (open access)

Bifurcations and Patterns in Nonlinear Dissipative Systems

This project consists of experimental investigations of heat transport, pattern formation, and bifurcation phenomena in non-linear non-equilibrium fluid-mechanical systems. These issues are studies in Rayleigh-B\'enard convection, using both pure and multicomponent fluids. They are of fundamental scientific interest, but also play an important role in engineering, materials science, ecology, meteorology, geophysics, and astrophysics. For instance, various forms of convection are important in such diverse phenomena as crystal growth from a melt with or without impurities, energy production in solar ponds, flow in the earth's mantle and outer core, geo-thermal stratifications, and various oceanographic and atmospheric phenomena. Our work utilizes computer-enhanced shadowgraph imaging of flow patterns, sophisticated digital image analysis, and high-resolution heat transport measurements.
Date: May 27, 2005
Creator: Ahlers, Guenter
Object Type: Report
System: The UNT Digital Library
Storage capacity for fissile material as a function of facility shape (room length-to-width ratio) (open access)

Storage capacity for fissile material as a function of facility shape (room length-to-width ratio)

None
Date: May 27, 1975
Creator: Altschuler, S. J.
Object Type: Report
System: The UNT Digital Library
Diffractive results from the Tevatron (open access)

Diffractive results from the Tevatron

Hard diffraction in events with dijets and rapidity gaps has been studied by D0 and CDF for three processes: hard color singlet exchange, hard single diffraction, and hard double pomeron exchange, using Tevatron {anti p}p data at {radical}s = 630 GeV and 1.8 TeV. Measurements of rates, {eta}, E{sub T} and {radical}s dependencies are presented and comparisons made with predictions of several models.
Date: May 27, 1999
Creator: Alves, Gilvan A.
Object Type: Article
System: The UNT Digital Library
The fractal nature of vacuum arc cathode spots (open access)

The fractal nature of vacuum arc cathode spots

Cathode spot phenomena show many features of fractals, for example self-similar patterns in the emitted light and arc erosion traces. Although there have been hints on the fractal nature of cathode spots in the literature, the fractal approach to spot interpretation is underutilized. In this work, a brief review of spot properties is given, touching the differences between spot type 1 (on cathodes surfaces with dielectric layers) and spot type 2 (on metallic, clean surfaces) as well as the known spot fragment or cell structure. The basic properties of self-similarity, power laws, random colored noise, and fractals are introduced. Several points of evidence for the fractal nature of spots are provided. Specifically power laws are identified as signature of fractal properties, such as spectral power of noisy arc parameters (ion current, arc voltage, etc) obtained by fast Fourier transform. It is shown that fractal properties can be observed down to the cutoff by measurement resolution or occurrence of elementary steps in physical processes. Random walk models of cathode spot motion are well established: they go asymptotically to Brownian motion for infinitesimal step width. The power spectrum of the arc voltage noise falls as 1/f {sup 2}, where f is frequency, …
Date: May 27, 2005
Creator: Anders, Andre
Object Type: Article
System: The UNT Digital Library
Strange-Particle Production by 1170-MeV/c pi- Mesons (open access)

Strange-Particle Production by 1170-MeV/c pi- Mesons

Production of {Lambda} + K{sup 0}, {Sigma}{sup 0} + K{sup 0}, and {Sigma}{sup -} + K{sup +} by 1170-MeV/c {pi}{sup -} mesons has been studied in the Lawrence Radiation Laboratory 72-inch hydrogen bubble chamber, Cross sections, angular distributions, and polarizations are presented. The polarization of the {Sigma}{sup 0} is determined at four center-of-mass angles and found to be small everywhere. Based on published results for the reaction {pi}{sup +} + p {yields} {Sigma}{sup +}, K{sup +}, a comparison of the polarizations of {Sigma}{sup +}, {Sigma}{sup -}, and {Sigma}{sup 0} is made from the charge-independence triangle. A conclusion is reached that the {Sigma}{sup -} polarization should be large, and that the {Sigma}{sup -} and {Sigma}{sup +} polarizations should be opposite in sign.
Date: May 27, 1963
Creator: Anderson, Jared Arnold
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider (open access)

Proposal of the Next Incarnation of Accelerator Test Facility at KEK for the International Linear Collider

To reach design luminosity, the International Linear Collider (ILC) must be able to create and reliably maintain nanometer size beams. The ATF damping ring is the unique facility where ILC emittances are possible. In this paper we present and evaluate the proposal to create a final focus facility at the ATF which, using compact final focus optics and an ILC-like bunch train, would be capable of achieving 37 nm beam size. Such a facility would enable the development of beam diagnostics and tuning methods, as well as the training of young accelerator physicists.
Date: May 27, 2005
Creator: Araki, S.; Hayano, H.; Higashi, Y.; Honda, Y.; Kanazawa, K.; Kubo, K. et al.
Object Type: Article
System: The UNT Digital Library
Turbulence-Flame Interactions in Type Ia Supernovae (open access)

Turbulence-Flame Interactions in Type Ia Supernovae

The large range of time and length scales involved in type Ia supernovae (SN Ia) requires the use of flame models. As a prelude to exploring various options for flame models, we consider, in this paper, high-resolution three-dimensional simulations of the small-scale dynamics of nuclear flames in the supernova environment in which the details of the flame structure are fully resolved. The range of densities examined, 1 to 8 x 107 g cm-3, spans the transition from the laminar flamelet regime to the distributed burning regime where small scale turbulence disrupts the flame. The use of a low Mach number algorithm facilitates the accurate resolution of the thermal structure of the flame and the inviscid turbulent kinetic energy cascade, while implicitly incorporating kinetic energy dissipation at the grid-scale cutoff. For an assumed background of isotropic Kolmogorov turbulence with an energy characteristic of SN Ia, we find a transition density between 1 and 3 x 107 g cm-3 where the nature of the burning changes ualitatively. By 1 x 107 g cm-3, energy diffusion by conduction and radiation is exceeded, on the flame scale, by turbulent advection. As a result, the effective Lewis Number approaches unity. That is, the flame resembles …
Date: May 27, 2008
Creator: Aspden, Andrew J.; Bell, John B.; Day, Marc S.; Woosley, Stan E. & Zingale, Mike
Object Type: Article
System: The UNT Digital Library
Search for b->u Transitions inB- -> D0 K- and B- -> D*0 K- (open access)

Search for b->u Transitions inB- -> D0 K- and B- -> D*0 K-

The authors search for B{sup -} {yields} {tilde D}{sup 0}K{sup -} and B{sup -} {yields} {tilde D}*{sup 0}K{sup -}, with {tilde D}*{sup 0} {yields} {tilde D}{sup 0}{pi}{sup 0} or {tilde D}*{sup 0} {yields} {tilde D}{sup 0}{gamma}, and {tilde D}{sup 0} {yields} K{sup +}{pi}{sup -} (and charge conjugates). These final states can be reached through the b {yields} c transition B{sup -} {yields} D{sup (*)0}K{sup -} followed by the doubly CKM-suppressed D{sup 0} {yields} K{sup +}{pi}{sup -}, or the b {yields} u transition B{sup -} {yields} {bar D}{sup (*)0}K{sup -} followed by the CKM-favored {bar D}{sup 0} {yields} K{sup +}{pi}{sup -}. The interference of these two amplitudes is sensitive to the angle {gamma} of the unitarity triangle. The results are based on 232 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at SLAC. They find no significant evidence for these decays. They set a limit r{sub B} {triple_bond} |A(B{sup -} {yields} {bar D}{sup 0}K{sup -})/A(B{sup -} {yields} D{sup 0}K{sup -})| < 0.23 at 90% C.L. using the most conservative assumptions on the values of the CKM angle {gamma} and the strong phases in the B and D decay amplitudes. In the case of the D* they set a …
Date: May 27, 2005
Creator: Aubert, B.; Barate, R.; Boutigny, D.; Couderc, F.; Karyotakis, Y.; Lees, J. P. et al.
Object Type: Article
System: The UNT Digital Library
Human events reference for ATHEANA (HERA) database description and preliminary user`s manual (open access)

Human events reference for ATHEANA (HERA) database description and preliminary user`s manual

The Technique for Human Error Analysis (ATHEANA) is a newly developed human reliability analysis (HRA) methodology that aims to facilitate better representation and integration of human performance into probabilistic risk assessment (PRA) modeling and quantification by analyzing risk-significant operating experience in the context of existing behavioral science models. The fundamental premise of ATHEANA is that error-forcing contexts (EFCs), which refer to combinations of equipment/material conditions and performance shaping factors (PSFs), set up or create the conditions under which unsafe actions (UAs) can occur. Because ATHEANA relies heavily on the analysis of operational events that have already occurred as a mechanism for generating creative thinking about possible EFCs, a database, called the Human Events Reference for ATHEANA (HERA), has been developed to support the methodology. This report documents the initial development efforts for HERA.
Date: May 27, 1998
Creator: Auflick, J.L.; Hahn, H.A. & Pond, D.J.
Object Type: Report
System: The UNT Digital Library
Prospects for Advances in Energy Conversion Technologies for Geothermal Energy Development (open access)

Prospects for Advances in Energy Conversion Technologies for Geothermal Energy Development

None
Date: May 27, 1975
Creator: Austin, A. L.
Object Type: Article
System: The UNT Digital Library
An efficient parallel termination detection algorithm (open access)

An efficient parallel termination detection algorithm

Information local to any one processor is insufficient to monitor the overall progress of most distributed computations. Typically, a second distributed computation for detecting termination of the main computation is necessary. In order to be a useful computational tool, the termination detection routine must operate concurrently with the main computation, adding minimal overhead, and it must promptly and correctly detect termination when it occurs. In this paper, we present a new algorithm for detecting the termination of a parallel computation on distributed-memory MIMD computers that satisfies all of those criteria. A variety of termination detection algorithms have been devised. Of these, the algorithm presented by Sinha, Kale, and Ramkumar (henceforth, the SKR algorithm) is unique in its ability to adapt to the load conditions of the system on which it runs, thereby minimizing the impact of termination detection on performance. Because their algorithm also detects termination quickly, we consider it to be the most efficient practical algorithm presently available. The termination detection algorithm presented here was developed for use in the PMESC programming library for distributed-memory MIMD computers. Like the SKR algorithm, our algorithm adapts to system loads and imposes little overhead. Also like the SKR algorithm, ours is tree-based, …
Date: May 27, 2004
Creator: Baker, A H; Crivelli, S & Jessup, E R
Object Type: Article
System: The UNT Digital Library
Dark Currents and Their Effect on the Primary Beam in an X-band Linac (open access)

Dark Currents and Their Effect on the Primary Beam in an X-band Linac

We numerically study properties of primary dark currents in an X-band accelerating structure. For the H60VG3 structure considered for the Next Linear Collider (NLC) we first perform a fairly complete (with some approximations) calculation of dark current trajectories. These results are used to study properties of the dark current leaving the structure. For example, at accelerating gradient of 65 MV/m, considering two very different assumptions about dark current emission around the irises, we find that the fraction of emitted current leaving the structure to be a consistent {approx} 1%. Considering that {approx} 1 mA outgoing dark current is seen in measurement, this implies that {approx} 100 mA (or 10 pC per period) is emitted within the structure itself. Using the formalism of the Lienard-Wiechert potentials, we then perform a systematic calculation of the transverse kick of dark currents on a primary linac bunch. The result is {approx} 1 V kick per mA (or per 0.1 pC per period) dark current emitted from an iris. For an entire structure we estimate the total kick on a primary bunch to be {approx} 15 V. For the NLC linac this translates to a ratio of (final) vertical beam offset to beam size of …
Date: May 27, 2005
Creator: Bane, K .L. F.; Dolgashev, V. A.; Raubenheimer, Tor; Stupakov, G. V. & Wu, J. H.
Object Type: Article
System: The UNT Digital Library
Damping beam displacements through phase mixing: an illustrative model (open access)

Damping beam displacements through phase mixing: an illustrative model

We develop a simple model of a beam transported in a hard wall channel (an idealized very-high-order magnetic-multipole channel). The extremely anharmonic nature of the potential leads to damping of coherent transverse displacements of the beam via phase mixing. For the case of small uniform displacements of the beam we can write down by inspection the analytical form of the motion of the beam centroid. The same technique allows us to evaluate the effects of focussing and scattering elements in the transport channel upon the damping of the transverse motion of the beam.
Date: May 27, 1983
Creator: Barletta, W. A. & Briggs, R. J.
Object Type: Article
System: The UNT Digital Library
Analysis of Positron Collection in the Linear Collider (open access)

Analysis of Positron Collection in the Linear Collider

In the Linear Collider, the positron capture system includes a positron production target, an adiabatic matching device (AMD), and a linac to accelerate positrons up to the injection energy of the positron damping ring. Efficiency of the positron collector is defined by the number of positrons accepted into the damping ring. Analysis of the positron collection system is performed using a conventional scheme, where positrons are produced by a high-energy electron beam hitting the high-Z target. The collection system has been optimized to insure high positron capture into the 6-dimensional acceptance of the damping ring. Various parameters affecting the positron capture are analyzed.
Date: May 27, 2005
Creator: Batygin, Yuri K.af SLAC
Object Type: Article
System: The UNT Digital Library
The Constitution of Zirconium-Uranium Alloys Containing Oxygen or Nitrogen (open access)

The Constitution of Zirconium-Uranium Alloys Containing Oxygen or Nitrogen

This report addresses the constitution of zirconium-uranium alloys containing oxygen or nitrogen.
Date: May 27, 1957
Creator: Bauer, Arthur A.; Beatty, Glen H.; Rough, Frank A. & Dickerson, Ronald F.
Object Type: Report
System: The UNT Digital Library
QCD and heavy flavor physics at high energy (open access)

QCD and heavy flavor physics at high energy

This talk summarizes recent results from the Tevatron Collider and HERA on QCD and Heavy Flavor physics
Date: May 27, 1999
Creator: Bedeschi, F.
Object Type: Article
System: The UNT Digital Library
Nuclear energy research initiative project final report. Report Period: October 1, 1999 - March 31, 2003 (open access)

Nuclear energy research initiative project final report. Report Period: October 1, 1999 - March 31, 2003

This project developed a single material approach to reducing nuclear waste volume based on a chemically functionalized porous silica that is termed Diphosil. Diphosil was created by Chiarizia and coworkers as an ion exchange medium that selectively and nearly irreversibly sorbs highly charged metal ions, such as actinides, from appreciably acidic aqueous solutions and a version of it is now commercially available. The chelating power of Diphosil is due to diphosphonic acid groups that are anchored to its silica surface via organic spacer groups. Approximately 90% of the weight of dry Diphosil is silica (SiO{sub 2}). Vitreous silica is one of the most radiation resistant glasses known.
Date: May 27, 2003
Creator: Beitz, J. V.
Object Type: Report
System: The UNT Digital Library
Polarized gun and ERL R and D for eRHIC (open access)

Polarized gun and ERL R and D for eRHIC

At Jefferson Laboratory charge density and charge lifetime during electron beam delivery are over 2 x 10{sup 5} C/cm{sup 2} and 200 C, respectively. A 200 C charge lifetime at 2 mA corresponds to 10{sup 5} seconds. In a more recent result, charge lifetimes of about an order of magnitude larger were achieved by a load-lock gun with a larger cathode area.
Date: May 27, 2009
Creator: Ben-Zvi, Ilan
Object Type: Article
System: The UNT Digital Library
Iteration of Planar Amplitudes inMaximally Supersymmetric Yang-Mills Theory at Three Loops (open access)

Iteration of Planar Amplitudes inMaximally Supersymmetric Yang-Mills Theory at Three Loops

We compute the leading-color (planar) three-loop four-point amplitude of N = 4 supersymmetric Yang-Mills theory in 4 - 2{epsilon} dimensions, as a Laurent expansion about {epsilon} = 0 including the finite terms. The amplitude was constructed previously via the unitarity method, in terms of two Feynman loop integrals, one of which has been evaluated already. Here we use the Mellin-Barnes integration technique to evaluate the Laurent expansion of the second integral. Strikingly, the amplitude is expressible, through the finite terms, in terms of the corresponding one- and two-loop amplitudes, which provides strong evidence for a previous conjecture that higher-loop planar N = 4 amplitudes have an iterative structure. The infrared singularities of the amplitude agree with the predictions of Sterman and Tejeda-Yeomans based on resummation. Based on the four-point result and the exponentiation of infrared singularities, we give an exponentiated ansatz for the maximally helicity-violating n-point amplitudes to all loop orders. The 1/{epsilon}{sup 2} pole in the four-point amplitude determines the soft, or cusp, anomalous dimension at three loops in N = 4 supersymmetric Yang-Mills theory. The result confirms a prediction by Kotikov, Lipatov, Onishchenko and Velizhanin, which utilizes the leading-twist anomalous dimensions in QCD computed by Moch, Vermaseren and …
Date: May 27, 2005
Creator: Bern, Zvi; Dixon, Lance J. & Smirnov, Vladimir A.
Object Type: Article
System: The UNT Digital Library
The Effect of Oxygen Contamination on the Amorphous Structure of Thermally Sprayed Coatings of Cu47Ti33Zr11Ni8Si1 (open access)

The Effect of Oxygen Contamination on the Amorphous Structure of Thermally Sprayed Coatings of Cu47Ti33Zr11Ni8Si1

this research has shown that it is possible to deposit coatings of gas atomized Cu{sub 47}Ti{sub 33}Zr{sub 11}Ni{sub 8}Si{sub 1} powders containing various levels of oxygen contamination using plasma arc spray methods. The structure of the coating was found to depend primarily on the spray environment, with an argon atmosphere producing the most amorphous samples for a given starting powder. The oxygen content of the coatings reflected the relative levels of the oxygen contamination in the starting powders. The analysis of the starting powders displayed oxygen contents ranging from 0.125-0.79 wt.%. It was shown that higher oxygen levels lead to more crystalline structure in the starting powders as determined by X-ray diffraction (XRD) and differential scanning calorimetry (DSC). This trend was found to be true for both the starting powders and for the plasma sprayed coatings. Chemical composition for all starting powders was very close to the nominal alloy composition. Chemical changes in the coatings involved the loss of Cu in coatings where high levels of oxidation were found. Cavitation erosion testing of selected coatings showed a weak trend that coatings prepared by vacuum plasma spray (VPS) had lower damage rates, but there was no clear data to indicate which …
Date: May 27, 2002
Creator: Besser, Matthew Frank
Object Type: Thesis or Dissertation
System: The UNT Digital Library
Coordination of Retail Demand Response with Midwest ISO Markets (open access)

Coordination of Retail Demand Response with Midwest ISO Markets

The Organization of Midwest ISO States (OMS) launched the Midwest Demand Resource Initiative (MWDRI) in 2007 to identify barriers to deploying demand response (DR) resources in the Midwest Independent System Operator (MISO) region and develop policies to overcome them. The MWDRI stakeholders decided that a useful initial activity would be to develop more detailed information on existing retail DR programs and dynamic pricing tariffs, program rules, and utility operating practices. This additional detail could then be used to assess any"seams issues" affecting coordination and integration of retail DR resources with MISO's wholesale markets. Working with state regulatory agencies, we conducted a detailed survey of existing DR programs, dynamic pricing tariffs, and their features in MISO states. Utilities were asked to provide information on advance notice requirements to customers, operational triggers used to call events (e.g. system emergencies, market conditions, local emergencies), use of these DR resources to meet planning reserves requirements, DR resource availability (e.g., seasonal, annual), participant incentive structures, and monitoring and verification (M&V) protocols. This report describes the results of this comprehensive survey and discusses policy implications for integrating legacy retail DR programs and dynamic pricing tariffs into organized wholesale markets. Survey responses from 37 MISO members and …
Date: May 27, 2008
Creator: Bharvirkar, Ranjit; Bharvirkar, Ranjit; Goldman, Charles; Heffner, Grayson & Sedano, Richard
Object Type: Article
System: The UNT Digital Library
Science and Technology Review July/August 2010 (open access)

Science and Technology Review July/August 2010

This issue has the following articles: (1) Deterrence with a Minimum Nuclear Stockpile - Commentary by Bruce T. Goodwin; (2) Enhancing Confidence in the Nation's Nuclear Stockpile - Livermore experts are participating in a national effort aimed at predicting how nuclear weapon materials and systems will likely change over time; (3) Narrowing Uncertainties - For climate modeling and many other fields, understanding uncertainty, or margin of error, is critical; (4) Insight into a Deadly Disease - Laboratory experiments reveal the pathogenesis of tularemia in host cells, bringing scientists closer to developing a vaccine for this debilitating disease. (5) Return to Rongelap - On the Rongelap Atoll, Livermore scientists are working to minimize radiological exposure for natives now living on or wishing to return to the islands.
Date: May 27, 2010
Creator: Blobaum, K M
Object Type: Report
System: The UNT Digital Library