Luminosity Determination in pp Collisions at sqrt(s)=7 TeV Using the ATLAS Detector at the LHC (open access)

Luminosity Determination in pp Collisions at sqrt(s)=7 TeV Using the ATLAS Detector at the LHC

None
Date: June 10, 2013
Creator: Aad, Georges
System: The UNT Digital Library
Tetraquark Interpretation of $E^ E^- \to \Upsilon \pi^ \pi^-$ Belle Data and $E^ E^- \to B \bar{b}$ BaBar Data (open access)

Tetraquark Interpretation of $E^ E^- \to \Upsilon \pi^ \pi^-$ Belle Data and $E^ E^- \to B \bar{b}$ BaBar Data

None
Date: June 10, 2013
Creator: Ali, Ahmed
System: The UNT Digital Library
Measuring Sparticles with the Matrix Element (open access)

Measuring Sparticles with the Matrix Element

We apply the Matrix Element Method (MEM) to mass determination of squark pair production with direct decay to quarks and LSP at the LHC, showing that simultaneous mass determination of squarks and LSP is possible. We furthermore propose methods for inclusion of QCD radiation effects in the MEM. The goal of the LHC at CERN, scheduled to start this year, is to discover new physics through deviations from the Standard Model (SM) predictions. After discovery of deviations from the SM, the next step will be classification of the new physics. An important first goal in this process will be establishing a mass spectrum of the new particles. One of the most challenging scenarios is pair-production of new particles which decay to invisible massive particles, giving missing energy signals. Many methods have been proposed for mass determination in such scenarios (for a recent list of references, see e.g. [1]). In this proceeding, we report the first steps in applying the Matrix Element Method (MEM) in the context of supersymmetric scenarios giving missing energy signals. After a quick review of the MEM, we will focus on squark pair production, a process where other mass determination techniques have difficulties to simultaneously determine the …
Date: April 10, 2012
Creator: Alwall, Johan; /SLAC /Taiwan, Natl. Taiwan U.; Freitas, Ayres; U., /Pittsburgh; Mattelaer, Olivier & /INFN, Rome3 /Rome III U. /Louvain U.
System: The UNT Digital Library
QCD Radiation in the Production of Heavy Colored Particles at the LHC (open access)

QCD Radiation in the Production of Heavy Colored Particles at the LHC

None
Date: July 10, 2013
Creator: Alwall, Johan; de Visscher, Simon & Maltoni, Fabio
System: The UNT Digital Library
Stauts of the Laser Inertial Fusion Energy (LIFE) Hohlraum Point Design (open access)

Stauts of the Laser Inertial Fusion Energy (LIFE) Hohlraum Point Design

Progress on the hohlraum point design for the LIFE engine is described. New features in the original design [Amendt et al., Fus. Sci. Technol. 60, 49 (2011)] are incorporated that address the imperatives of low target cost, high manufacturing throughput, efficient and prompt material recycling, an ability for near-term testing of key target design uncertainties on the National Ignition Facility, and robustness to target chamber environment and injection insults. To this end, the novel use of Pb hohlraums and aerogel-supported liquid DT fuel loading within a high-density-carbon (HDC) ablator is implemented in the hohlraum point design.
Date: April 10, 2012
Creator: Amendt, P.; Dunne, M.; Ho, D.; Lasinski, B.; Meeker, D. & Ross, J. S.
System: The UNT Digital Library
The SM and NLO Multileg Working Group: Summary Report (open access)

The SM and NLO Multileg Working Group: Summary Report

After years of waiting, and after six Les Houches workshops, the era of LHC running is finally upon us, albeit at a lower initial center-of-mass energy than originally planned. Thus, there has been a great sense of anticipation from both the experimental and theoretical communities. The last two years, in particular, have seen great productivity in the area of multi-parton calculations at leading order (LO), next-to-leading order (NLO) and next-to-next-to-leading order (NNLO), and this productivity is reflected in the proceedings of the NLM group. Both religions, Feynmanians and Unitarians, as well as agnostic experimenters, were well-represented in both the discussions at Les Houches, and in the contributions to the write-up. Next-to-leading order (NLO) is the first order at which the normalization, and in some cases the shape, of perturbative cross sections can be considered reliable. This can be especially true when probing extreme kinematic regions, as for example with boosted Higgs searches considered in several of the contributions to this writeup. A full understanding for both standard model and beyond the standard model physics at the LHC requires the development of fast, reliable programs for the calculation of multi-parton final states at NLO. There have been many advances in the …
Date: April 10, 2012
Creator: Andersen, J. R.; Archibald, J.; Badger, S.; Ball, R. D.; Bevilacqua, G.; Bierenbaum, I. et al.
System: The UNT Digital Library
Search for Solar Axion Emission from 7Li and D(p,gamma)3He Nuclear Decays with the CAST gamma-ray Calorimeter (open access)

Search for Solar Axion Emission from 7Li and D(p,gamma)3He Nuclear Decays with the CAST gamma-ray Calorimeter

None
Date: July 10, 2013
Creator: Andriamonje, S.; Aune, S.; Autiero, D.; Barth, K.; Belov, A.; Beltran, B. et al.
System: The UNT Digital Library
6D cooling in periodic lattices including a planar snake (open access)

6D cooling in periodic lattices including a planar snake

N/A
Date: June 10, 2013
Creator: B., Palmer R.; Berg, J. S. & Stratakis, D,
System: The UNT Digital Library
An Initial Evaluation Of Characterization And Closure Options For Underground Pipelines Within A Hanford Site Single-Shell Tank Farm (open access)

An Initial Evaluation Of Characterization And Closure Options For Underground Pipelines Within A Hanford Site Single-Shell Tank Farm

The Hanford Site includes 149 single-shell tanks, organized in 12 'tank farms,' with contents managed as high-level mixed waste. The Hanford Federal Facility Agreement and Consent Order requires that one tank farm, the Waste Management Area C, be closed by June 30, 2019. A challenge to this project is the disposition and closure of Waste Management Area C underground pipelines. Waste Management Area C contains nearly seven miles of pipelines and 200 separate pipe segments. The pipelines were taken out of service decades ago and contain unknown volumes and concentrations of tank waste residuals from past operations. To understand the scope of activities that may be required for these pipelines, an evaluation was performed. The purpose of the evaluation was to identify what, if any, characterization methods and/or closure actions may be implemented at Waste Management Area C for closure of Waste Management Area C by 2019. Physical and analytical data do not exist for Waste Management Area C pipeline waste residuals. To develop estimates of residual volumes and inventories of contamination, an extensive search of available information on pipelines was conducted. The search included evaluating historical operation and occurrence records, physical attributes, schematics and drawings, and contaminant inventories associated …
Date: January 10, 2013
Creator: Badden, Janet W.; Connelly, Michael P.; Seeley, Paul N. & Hendrickson, Michelle L.
System: The UNT Digital Library
Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab (open access)

Mechanical Design of a High Energy Beam Absorber for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab

A high energy beam absorber has been built for the Advanced Superconducting Test Accelerator (ASTA) at Fermilab. In the facility's initial configuration, an electron beam will be accelerated through 3 TTF-type or ILC-type SRF cryomodules to an energy of 750MeV. The electron beam will be directed to one of multiple downstream experimental and diagnostic beam lines and then deposited in one of two beam absorbers. The facility is designed to accommodate up to 6 cryomodules, which would produce a 75kW beam at 1.5GeV; this is the driving design condition for the beam absorbers. The beam absorbers consist of water-cooled graphite, aluminum and copper layers contained in a helium-filled enclosure. This paper describes the mechanical implementation of the beam absorbers, with a focus on thermal design and analysis. The potential for radiation-induced degradation of the graphite is discussed.
Date: May 10, 2012
Creator: Baffes, C.; Church, M.; Leibfritz, J.; Oplt, S. & Rakhno, I.
System: The UNT Digital Library
Simulation of free-electron lasers seeded with broadband radiation (open access)

Simulation of free-electron lasers seeded with broadband radiation

The longitudinal coherence of free-electron laser (FEL) radiation can be enhanced by seeding the FEL with high harmonics of an optical laser pulse. The radiation produced by high-harmonic generation (HHG), however, has a fast-varying temporal profile that can violate the slowly varying envelope approximation and limited frequency window that is employed in conventional free-electron laser simulation codes. Here we investigate the implications of violating this approximation on the accuracy of simulations. On the basis of both analytical considerations and 1D numerical studies, it is concluded that, for most realistic scenarios, conventional FEL codes are capable of accurately simulating the FEL process even when the seed radiation violates the slowly varying envelope approximation. We additionally discuss the significance of filtering the harmonic content of broadband HHG seeds.
Date: March 10, 2011
Creator: Bajlekov, Svetoslav; Fawley, William; Schroeder, Carl; Bartolini, Riccardo & Hooker, Simon
System: The UNT Digital Library
Multigrid Smoothers for Ultra-Parallel Computing (open access)

Multigrid Smoothers for Ultra-Parallel Computing

None
Date: March 10, 2011
Creator: Baker, A H; Falgout, R D; Kolev, T V & Yang, U M
System: The UNT Digital Library
Lepton Universality, |V(Us)| and Search for Second Class Current in Tau Decays (open access)

Lepton Universality, |V(Us)| and Search for Second Class Current in Tau Decays

Several hundred million {tau} decays have been studied with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory. Recent results on Charged Current Lepton Universality and two independent measurements of |V{sub us}| using {tau}{sup -} {yields} e{sup -}{bar {nu}}{sub e}{nu}{sub {tau}}, {mu}{sup -}{bar {nu}}{sub {mu}}{nu}{sub {tau}}, {pi}{sup -}{nu}{sub {tau}}, K{sup -} {nu}{sub {tau}} and K{sub S}{sup 0}{pi}{sup -} {nu}{sub {tau}} decays, and a search for Second Class Current in {tau}{sup -} {yields} {pi}{sup -} {omega}{nu}{sub {tau}} decays are presented, where the charge conjugate decay modes are also implied.
Date: November 10, 2011
Creator: Banerjee, Swagato
System: The UNT Digital Library
Leptonic B Decays at BaBar (open access)

Leptonic B Decays at BaBar

We will present the most recent results on leptonic B decays B{sup {+-}(0)} {yields} K*{sup {+-}(0)}{nu}{bar {nu}} and B{sup {+-}} {yields} {mu}{sup {+-}}{nu}, based on the data collected by the BaBar detector at PEP-II, an asymmetric e{sup +}e{sup -} collider at the center of mass energy of the {Upsilon}(4S) resonance. Rare B decays have always been a standard probe for New Physics (NP) searches. The very low Standard Model (SM) rate of these decays often make them unaccessible with the present experimental datasets, unless NP effects enhance the rate up to the current experimental sensitivity. Moreover, as NP effects can modify the decay kinematic, particular attention must be paid in order to perform a model independent analysis. A B-Factory provides an unique environment to investigate these processes. The high number of B{bar B} pairs produced by a B-Factory often allows to approach the needed experimental sensitivity. Moreover, the clean environment and the closed kinematic of the initial state enable to obtaining a very pure sample where to look for these decays.
Date: November 10, 2011
Creator: Baracchini, Elisabetta
System: The UNT Digital Library
On the effect of x-ray irradiation on the deformation and fracture behavior of human cortical bone (open access)

On the effect of x-ray irradiation on the deformation and fracture behavior of human cortical bone

In situ mechanical testing coupled with imaging using high-energy synchrotron x-ray diffraction or tomography imaging is gaining in popularity as a technique to investigate micrometer and even sub-micrometer deformation and fracture mechanisms in mineralized tissues, such as bone and teeth. However, the role of the irradiation in affecting the nature and properties of the tissue is not always taken into account. Accordingly, we examine here the effect of x-ray synchrotron-source irradiation on the mechanistic aspects of deformation and fracture in human cortical bone. Specifically, the strength, ductility and fracture resistance (both work-of-fracture and resistance-curve fracture toughness) of human femoral bone in the transverse (breaking) orientation were evaluated following exposures to 0.05, 70, 210 and 630 kGy irradiation. Our results show that the radiation typically used in tomography imaging can have a major and deleterious impact on the strength, post-yield behavior and fracture toughness of cortical bone, with the severity of the effect progressively increasing with higher doses of radiation. Plasticity was essentially suppressed after as little as 70 kGy of radiation; the fracture toughness was decreased by a factor of five after 210 kGy of radiation. Mechanistically, the irradiation was found to alter the salient toughening mechanisms, manifest by the …
Date: January 10, 2010
Creator: Barth, Holly D.; Launey, Maximilien E.; McDowell, Alastair A.; Ager, Joel W., III & Ritchie, Robert O.
System: The UNT Digital Library
Exploring the Outer Solar System with the ESSENCE Supernova Survey (open access)

Exploring the Outer Solar System with the ESSENCE Supernova Survey

We report the discovery and orbital determination of 14 trans-Neptunian objects (TNOs) from the ESSENCE Supernova Survey difference imaging data set. Two additional objects discovered in a similar search of the SDSS-II Supernova Survey database were recovered in this effort. ESSENCE repeatedly observed fields far from the solar system ecliptic (-21{sup o} < {beta} < -5{sup o}), reaching limiting magnitudes per observation of I {approx} 23.1 and R {approx} 23.7. We examine several of the newly detected objects in detail, including 2003 UC{sub 414}, which orbits entirely between Uranus and Neptune and lies very close to a dynamical region that would make it stable for the lifetime of the solar system. 2003 SS{sub 422} and 2007 TA{sub 418} have high eccentricities and large perihelia, making them candidate members of an outer class of TNOs. We also report a new member of the 'extended' or 'detached' scattered disk, 2004 VN{sub 112}, and verify the stability of its orbit using numerical simulations. This object would have been visible to ESSENCE for only {approx}2% of its orbit, suggesting a vast number of similar objects across the sky. We emphasize that off-ecliptic surveys are optimal for uncovering the diversity of such objects, which in …
Date: November 10, 2011
Creator: Becker, A. C.; Arraki, K.; Kaib, N. A.; Wood-Vasey, W. M.; Aguilera, C.; Blackman, J. W. et al.
System: The UNT Digital Library
Mach-Zehnder Modulator Performance Using the Comet Laser Facility and Implications for Use on NIF (open access)

Mach-Zehnder Modulator Performance Using the Comet Laser Facility and Implications for Use on NIF

None
Date: July 10, 2012
Creator: Beeman, B.; MacPhee, A. G.; Kimbrough, J. R.; Lacaille, G. A.; Barrios, M. A.; Emig, J. et al.
System: The UNT Digital Library
On the Lack of Evolution in Galaxy Star Formation Efficiency (open access)

On the Lack of Evolution in Galaxy Star Formation Efficiency

None
Date: December 10, 2012
Creator: Behroozi, Peter S.; Wechsler, Risa H.; /KIPAC, Menlo Park /SLAC; Conroy, Charlie & /UC, Santa Cruz, Astron. Astrophys.
System: The UNT Digital Library
RAYLEIGH-TAYLOR STRENGTH EXPERIMENTS OF THE PRESSURE-INDUCED alpha->epsilon->alpha' PHASE TRANSITION IN IRON (open access)

RAYLEIGH-TAYLOR STRENGTH EXPERIMENTS OF THE PRESSURE-INDUCED alpha->epsilon->alpha' PHASE TRANSITION IN IRON

We present here the first dynamic Rayleigh-Taylor (RT) strength measurement of a material undergoing solid-solid phase transition. Iron is quasi-isentropically driven across the pressure-induced bcc ({alpha}-Fe) {yields} hcp ({var_epsilon}-Fe) phase transition and the dynamic strength of the {alpha}, {var_epsilon} and reverted {alpha}{prime} phases have been determined via proton radiography of the resulting Rayleigh-Taylor unstable interface between the iron target and high-explosive products. Simultaneous velocimetry measurements of the iron free surface yield the phase transition dynamics and, in conjunction with detailed hydrodynamic simulations, allow for determination of the strength of the distinct phases of iron. Forward analysis of the experiment via hydrodynamic simulations reveals significant strength enhancement of the dynamically-generated {var_epsilon}-Fe and reverted {alpha}{prime}-Fe, comparable in magnitude to the strength of austenitic stainless steels.
Date: August 10, 2011
Creator: Belof, J. L.; Cavallo, R. M.; Olson, R. T.; King, R. S.; Gray, G. T.; Holtkamp, D. B. et al.
System: The UNT Digital Library
A Prognostic Method for Scheduling Maintenance on the P2- Marx Modulator (open access)

A Prognostic Method for Scheduling Maintenance on the P2- Marx Modulator

The SLAC National Accelerator Laboratory is developing a second generation Marx-type modulator for the ILC, the P2-Marx. The modulator is expected to operate reliably in excess of 10{sup 5} hours with minimum downtime. A prognostic system is being implemented with the development of the P2-Marx to monitor and track the health of key high voltage components. This paper discusses the way in which the prognostic system will be implemented and used to monitor the health of the P2-Marx modulator.
Date: June 10, 2010
Creator: Benwell, Andrew; Burkhart, Craig; Kemp, Mark; Macken, Koen; Nguyen, Minh; MacNair, Dave et al.
System: The UNT Digital Library
High Multiplicity W Jets Predictions at NLO (open access)

High Multiplicity W Jets Predictions at NLO

None
Date: September 10, 2013
Creator: Bern, Z.; Dixon, L.J.; Cordero, F.Febres; Hoche, S.; Ita, H.; Kosower, D.A. et al.
System: The UNT Digital Library
An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System (open access)

An Exact SU(2) Symmetry and Persistent Spin Helix in a Spin-Orbit Coupled System

Spin-orbit coupled systems generally break the spin rotation symmetry. However, for a model with equal Rashba and Dresselhauss coupling constant (the ReD model), and for the [110] Dresselhauss model, a new type of SU(2) spin rotation symmetry is discovered. This symmetry is robust against spin-independent disorder and interactions, and is generated by operators whose wavevector depends on the coupling strength. It renders the spin lifetime infinite at this wavevector, giving rise to a Persistent Spin Helix (PSH). We obtain the spin fluctuation dynamics at, and away, from the symmetry point, and suggest experiments to observe the PSH.
Date: February 10, 2010
Creator: Bernevig, Andrei
System: The UNT Digital Library
DEPLOYMENT OF THE BULK TRITIUM SHIPPING PACKAGE (open access)

DEPLOYMENT OF THE BULK TRITIUM SHIPPING PACKAGE

A new Bulk Tritium Shipping Package (BTSP) was designed by the Savannah River National Laboratory to be a replacement for a package that has been used to ship tritium in a variety of content configurations and forms since the early 1970s. The BTSP was certified by the National Nuclear Safety Administration in 2011 for shipments of up to 150 grams of Tritium. Thirty packages were procured and are being delivered to various DOE sites for operational use. This paper summarizes the design features of the BTSP, as well as associated engineered material improvements. Fabrication challenges encountered during production are discussed as well as fielding requirements. Current approved tritium content forms (gas and tritium hydrides), are reviewed, as well as, a new content, tritium contaminated water on molecular sieves. Issues associated with gas generation will also be discussed.
Date: October 10, 2013
Creator: Blanton, P.
System: The UNT Digital Library
DEVELOPMENT OF THE HS99 AIR TRANSPORT TYPE A FISSILE PACKAGE (open access)

DEVELOPMENT OF THE HS99 AIR TRANSPORT TYPE A FISSILE PACKAGE

An air-transport Type A Fissile radioactive shipping package for the transport of special form uranium sources has been developed by the Savannah River National Laboratory (SRNL) for the Department of Homeland Security. The Package model number is HS99 for Homeland Security Model 99. This paper presents the major design features of the HS99 and highlights engineered materials necessary for meeting the design requirements for this light-weight Type AF packaging. A discussion is provided demonstrating how the HS99 complies with the regulatory safety requirements of the Nuclear Regulatory Commission. The paper summarizes the results of structural testing to specified in 10 CFR 71 for Normal Conditions of Transport and Hypothetical Accident Conditions events. Planned and proposed future missions for this packaging are also addressed.
Date: July 10, 2012
Creator: Blanton, P. & Eberl, K.
System: The UNT Digital Library