Degree Department

51 Matching Results

Results open in a new window/tab.

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
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
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
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
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
The Baytown Sun (Baytown, Tex.), Vol. 89, No. 54, Ed. 1 Monday, February 23, 2009 (open access)

The Baytown Sun (Baytown, Tex.), Vol. 89, No. 54, Ed. 1 Monday, February 23, 2009

Daily newspaper from Baytown, Texas that includes local, state, and national news along with advertising.
Date: February 23, 2009
Creator: Clements, Clifford E.
Object Type: Newspaper
System: The Portal to Texas History
Comparison of fast 3D simulation and actinic inspection for EUV masks with buries defects (open access)

Comparison of fast 3D simulation and actinic inspection for EUV masks with buries defects

Aerial images for isolated defects and the interactions of defects with features are compared between the Actinic Inspection Tool (AIT) at Lawrence Berkeley National Laboratory (LBNL) and the fast EUV simulation program RADICAL. Comparisons between AIT images from August 2007 and RADICAL simulations are used to extract aberrations. At this time astigmatism was the dominant aberration with a value of 0.55 waves RMS. Significant improvements in the imaging performance of the AIT were made between August 2007 and December 2008. A good match will be shown between the most recent AIT images and RADICAL simulations without aberrations. These comparisons will demonstrate that a large defect, in this case 7nm tall on the surface, is still printable even if it is centered under the absorber line. These comparisons also suggest that the minimum defect size is between 1.5nm and 0.8nm surface height because a 1.5nm defect was printable but a 0.8nm was not. Finally, the image of a buried defect near an absorber line through focus will demonstrate an inversion in the effect of the defect from a protrusion of the dark line into the space to a protrusion of the space into the line.
Date: February 23, 2009
Creator: Clifford, C. H.; Wiraatmadja, S.; Chan, T. T.; Neureuther, A. R.; Goldberg, K. A.; Mochi, I. et al.
Object Type: Article
System: The UNT Digital Library
End-of-Life Care: Services, Costs, Ethics, and Quality of Care (open access)

End-of-Life Care: Services, Costs, Ethics, and Quality of Care

This report provides information on various aspects of end-of-life care: (1) demographic and historical changes affecting death and dying in the United States (2) the definitions of end-of-life, palliative, and hospice care (3) costs associated with end-of-life care (4) end-of-life care laws and ethics (5) quality of care at the end of life and (6) policy issues that would modify or expand the federal government's role in addressing end-of-life care.
Date: February 23, 2009
Creator: Colello, Kirsten J.; Mulvey, Janemarie; Sarata, Amanda K.; Williams, Erin D. & Thomas, Kenneth R.
Object Type: Report
System: The UNT Digital Library
Dalitz Plot Analysis of B+- --> pi+-pi+-pi-+ Decays (open access)

Dalitz Plot Analysis of B+- --> pi+-pi+-pi-+ Decays

The authors present a Dalitz-plot analysis of charmless B{sup {+-}} decays to the final state {pi}{sup {+-}}{pi}{sup {+-}}{pi}{sup {-+}} using a sample of (465 {+-} 5) x 10{sup 6} B{bar B} pairs collected by the BABAR experiment at {radical}s = 10.58 GeV. They measure the branching fractions {Beta}(B{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup {+-}}{pi}{sup {-+}}) = (15.2 {+-} 0.6 {+-} 1.2 {+-} 0.4) x 10{sup -6}, {Beta}(B{sup {+-}} {yields} {rho}{sup 0}(770){pi}{sup {+-}}) = (8.1 {+-} 0.7 {+-} 1.2{sub -1.1}{sup +0.4}) x 10{sup -6}, {Beta}(B{sup {+-}} {yields} f{sub 2}(1270){pi}{sup {+-}}) = (1.57 {+-} 0.42 {+-} 0.16{sub -0.19}{sup +0.53}) x 10{sup -6}, and {Beta}(B{sup {+-}} {yields} {pi}{sup {+-}}{pi}{sup {+-}}{pi}{sup {-+}} nonresonant) = (5.3 {+-} 0.7 {+-} 0.6{sub -0.5}{sup +1.1}) x 10{sup -6}, where the uncertainties are statistical, systematic, and model-dependent, respectively. Measurements of branching fractions for the modes B{sup {+-}} {yields} {rho}{sup 0}(1450){pi}{sup {+-}} and B{sup {+-}} {yields} f{sub 0}(1370){pi}{sup {+-}} are also presented. They observe no significant direct CP asymmetries for the above modes, and there is no evidence for the decays B{sup {+-}} {yields} f{sub 0}(980){pi}{sup {+-}}, B{sup {+-}} {yields} {chi}{sub c0}{pi}{sup {+-}}, or B{sup {+-}} {yields} {chi}{sub c2}{pi}{sup {+-}}.
Date: February 23, 2009
Creator: Collaboration, The BABAR & Aubert, B.
Object Type: Article
System: The UNT Digital Library
Metastable Supersymmetry Breaking and Multitrace Deformations of SQCD (open access)

Metastable Supersymmetry Breaking and Multitrace Deformations of SQCD

Metastable vacua in supersymmetric QCD in the presence of single and multitrace deformations of the superpotential are explored, with the aim of obtaining an acceptable phenomenology. The metastable vacua appear at one loop, have a broken R-symmetry, and a magnetic gauge group that is completely Higgsed. With only a single trace deformation, the adjoint fermions from the meson superfield are approximately massless at one loop, even though they are massive at tree level and R-symmetry is broken. Consequently, if charged under the standard model, they are unacceptably light. A multitrace quadratic deformation generates fermion masses proportional to the deformation parameter. Phenomenologically viable models of direct gauge mediation can then be obtained, and some of their features are discussed.
Date: February 23, 2009
Creator: Essig, Rouven; Fortin, Jean-Francois; Sinha, Kuver; Torroba, Gonzalo & Strassler, Matthew J.
Object Type: Article
System: The UNT Digital Library
MARFE Stability and Movement in an ELMy H-mode NSTX Discharge (open access)

MARFE Stability and Movement in an ELMy H-mode NSTX Discharge

The results of a comparison of Multifaceted Asymmetric Radiation From the Edge (MARFE) theory with experiment in the National Spherical Torus Experiment (NSTX) are presented. A variety of MARFE behavior was observed using a fast-framing camera. A basic MARFE theory was applied to NSTX Multi-Pulse Thomson scattering (MPTS) and charge-exchange recombination spectroscopy (CHERS) data. MARFE theory showed some limited agreement with experiment, but uncertainty in the separatrix location constrained the analysis. A method based on shifting iso-Te flux surfaces was used to estimate the separatrix location. The movements of MARFEs in NSTX are interpreted to result from diamagnetic heat flux driven drifts relative to the background plasma velocity and imply slowing edge poloidal rotation and/or changing edge profiles before a large ELM.
Date: February 23, 2009
Creator: F. Kelly, R. Maingi, R. Maqueda, J. Menard, S. Paul
Object Type: Report
System: The UNT Digital Library
Human Services Provisions of the American Recovery and Reinvestment Act (open access)

Human Services Provisions of the American Recovery and Reinvestment Act

This report discusses provisions of the American Recovery and Reinvestment Act of 2009 (ARRA) for selected human services programs. The selected programs generally are those that provide benefits and services to families with children, though some programs (e.g., the Community Services Block Grant) provide services to other families as well. All of the programs discussed in this report are administered by the Department of Health and Human Services (HHS).
Date: February 23, 2009
Creator: Falk, Gene; Lynch, Karen E.; Solomon-Fears, Carmen; Perl, Libby; Richardson, Joe & Spar, Karen
Object Type: Report
System: The UNT Digital Library
Carbon Capture and Sequestration (open access)

Carbon Capture and Sequestration

This report covers carbon capture and sequestration (CCS), but not other types of carbon sequestration activities whereby CO2 is removed from the atmosphere and stored in vegetation, soils, or oceans. Forests and agricultural lands store carbon, and the world's oceans exchange huge amounts of CO2 from the atmosphere through natural processes.
Date: February 23, 2009
Creator: Folger, Peter
Object Type: Report
System: The UNT Digital Library
Out-of-band exposure characterization with the SEMATECH Berkeley 0.3-NA microfield exposure tool (open access)

Out-of-band exposure characterization with the SEMATECH Berkeley 0.3-NA microfield exposure tool

For the commercialization of extreme ultraviolet lithography (EUVL), discharge or laser produced, pulsed plasma light sources are being considered. These sources are known to emit into a broad range of wavelengths that are collectively referred to as the out-of-band (OOB) radiation by lithographers. Multilayer EUV optics reflect OOB radiation emitted by the EUV sources onto the wafer plane resulting in unwanted background exposure of the resist (flare) and reduced image contrast. The reflectivity of multilayer optics at the target wavelength of 13.5 nm is comparable to that of their reflectivity in the deep ultraviolet (DUV) and UV regions from 100-350 nm. The aromatic molecular backbones of many of the resists used for EUV are equally absorptive at specific DUV wavelengths as well. In order to study the effect of these wavelengths on imaging performance in a real system, we are in the process of integrating a DUV source into the SEMATECH Berkeley 0.3-NA Microfield Exposure Tool (MET). The MET plays an active role in advanced research in resist and mask development for EUVL and as such, we will utilize this system to systematically evaluate the imaging impact of DUV wavelengths in a EUV system. In this paper, we present the …
Date: February 23, 2009
Creator: George, Simi A.; Nauleau, Patrick; Rekawa, Senajith; Gullikson, Eric & Kemp, Charles D.
Object Type: Article
System: The UNT Digital Library
Collecting EUV mask images through focus by wavelength tuning (open access)

Collecting EUV mask images through focus by wavelength tuning

Using an extreme-ultraviolet (EUV) microscope to produce high-quality images of EUV reticles, we have developed a new wavelength tuning method to acquire through-focus data series with a higher level of stability and repeatability than was previously possible. We utilize the chromatic focal-length dependence of a diffractive Fresnel zoneplate objective lens, and while holding the mask sample mechanically still, we tune the wavelength through a narrow range, in small steps. In this paper, we demonstrate the method and discuss the relative advantages that this data collection technique affords.
Date: February 23, 2009
Creator: Goldberg, Kenneth A.; Mochi, Iacopo & Huh, Sungmin
Object Type: Article
System: The UNT Digital Library
Effects of Energy Chirp on Echo-Enabled Harmonic Generation Free-Electron Lasers (open access)

Effects of Energy Chirp on Echo-Enabled Harmonic Generation Free-Electron Lasers

We study effects of energy chirp on echo-enabled harmonic generation (EEHG). Analytical expressions are compared with numerical simulations for both harmonic and bunching factors. We also discuss the EEHG free-electron laser bandwidth increase due to an energy-modulated beam and its pulse length dependence on the electron energy chirp.
Date: February 23, 2009
Creator: Huang, Z.; Ratner, D.; Stupakov, G. & Xiang, D.
Object Type: Report
System: The UNT Digital Library
Climate Change: Science Highlights (open access)

Climate Change: Science Highlights

This report summarizes highlights of scientific research and assessments related to human-induced climate change.
Date: February 23, 2009
Creator: Leggett, Jane A.
Object Type: Report
System: The UNT Digital Library
ZPR-6 Assembly 7 High {Sup 240}Pu Core Experiments : A Fast Reactor Core With Mixed (Pu,U)-Oxide Fuel and a Centeral High{Sup 240}Pu Zone. (open access)

ZPR-6 Assembly 7 High {Sup 240}Pu Core Experiments : A Fast Reactor Core With Mixed (Pu,U)-Oxide Fuel and a Centeral High{Sup 240}Pu Zone.

ZPR-6 Assembly 7 (ZPR-6/7) encompasses a series of experiments performed at the ZPR-6 facility at Argonne National Laboratory in 1970 and 1971 as part of the Demonstration Reactor Benchmark Program (Reference 1). Assembly 7 simulated a large sodium-cooled LMFBR with mixed oxide fuel, depleted uranium radial and axial blankets, and a core H/D near unity. ZPR-6/7 was designed to test fast reactor physics data and methods, so configurations in the Assembly 7 program were as simple as possible in terms of geometry and composition. ZPR-6/7 had a very uniform core assembled from small plates of depleted uranium, sodium, iron oxide, U{sub 3}O{sub 8} and Pu-U-Mo alloy loaded into stainless steel drawers. The steel drawers were placed in square stainless steel tubes in the two halves of a split table machine. ZPR-6/7 had a simple, symmetric core unit cell whose neutronic characteristics were dominated by plutonium and {sup 238}U. The core was surrounded by thick radial and axial regions of depleted uranium to simulate radial and axial blankets and to isolate the core from the surrounding room. The ZPR-6/7 program encompassed 139 separate core loadings which include the initial approach to critical and all subsequent core loading changes required to perform …
Date: February 23, 2009
Creator: Lell, R. M.; Morman, J. A.; Schaefer, R.W. & McKnight, R.D.
Object Type: Report
System: The UNT Digital Library
Coal Mine Safety and Health (open access)

Coal Mine Safety and Health

This report begins by reviewing the record of working conditions in the coal mining industry. It then describes the regulatory regime of the U.S. Department of Labor's Mine Safety and Health Administration, incorporating discussion of the standard-setting required by the Mine Improvement and New Emergency Response Act of 2006. The report closes with an examination of recent legislative initiatives.
Date: February 23, 2009
Creator: Levine, Linda
Object Type: Report
System: The UNT Digital Library
Deliquescence and efflorescence of small particles: Unifying perspectives from nucleation theory (open access)

Deliquescence and efflorescence of small particles: Unifying perspectives from nucleation theory

We examine size dependent deliquescence/efflorescence phase transformation for particles down to several nanometers in size. A thin layer criterion (TLC) is introduced to define a deliquescence relative humidity (DRH) for small particles. The usual bulk deliquescence conditions are recovered in the limit of large dry particle size. Nano-size particles are shown to deliquesce to metastable states via a nucleation process at relative humidity just below the DRH. The nucleation barrier is located at a critical solution layer thickness and vanishes at the DRH defined by the TLC. Methods from nucleation theory form the basis for the analysis and yield new insights into the theory, facilitate the interpretation of measurements, and point to unification of deliquescence and efflorescence processes for particles in the nano regime. Methods include thermodynamic area constructions, Legendre transforms relating the binary free-energy surfaces for deliquescence and efflorescence processes, and application of nucleation theorems.
Date: February 23, 2009
Creator: McGraw,R. & Lewis, E.
Object Type: Article
System: The UNT Digital Library
Agriculture, Nutrition, and Rural Provisions in the American Recovery and Reinvestment Act (ARRA) of 2009 (open access)

Agriculture, Nutrition, and Rural Provisions in the American Recovery and Reinvestment Act (ARRA) of 2009

This report analyzes the agriculture, nutrition, and rural provisions in the American Recovery and Reinvestment Act of 2009 (ARRA, P.L. 111-5). The ARRA boosts government spending on various infrastructure programs and government benefits programs, and offers individual and business tax benefits.
Date: February 23, 2009
Creator: Monke, Jim; Richardson, Joe; Stubbs, Megan; Cowan, Tadlock; Chite, Ralph M.; Becker, Geoffrey S. et al.
Object Type: Report
System: The UNT Digital Library