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D/sup -/ production by multiple charge-transfer collisions of low-energy D ions and atoms in cesium vapor (open access)

D/sup -/ production by multiple charge-transfer collisions of low-energy D ions and atoms in cesium vapor

The production of D/sup -/ by multiple charge-transfer collisions of a D/sup +/ beam in a cesium-vapor target is considered for D/sup +/ energies above 300 eV. The cross sections relevant to D/sup -/ formation are obtained by a least-squares fit of three-charge-state differential equations to experimental yield curves. Implications for production of intense negative-ion beams are discussed, and speculations are made about extrapolation to lower engeries.
Date: January 22, 1978
Creator: Hooper, E. B. Jr.; Willmann, P. A. & Schlachter, A. S.
Object Type: Report
System: The UNT Digital Library
Estimating Adipose Tissue in the Chest Wall Using Ultrasonic and Alternate /sup 40/K and Biometric Measurements (open access)

Estimating Adipose Tissue in the Chest Wall Using Ultrasonic and Alternate /sup 40/K and Biometric Measurements

The percentage of adipose (fat) tissue in the chest wall must be known to accurately measure Pu in the human lung. Correction factors of 100% or more in x-ray detection efficiency are common. Methods using simple /sup 40/K and biometric measurement techniques were investigated to determine the adipose content in the human chest wall. These methods predict adipose content to within 15% of the absolute ultrasonic value. These new methods are discussed and compared with conventional ultrasonic measurement techniques. (ERB)
Date: January 22, 1982
Creator: Anderson, A. L. & Campbell, G. W.
Object Type: Article
System: The UNT Digital Library
Combustion Research Program: Flame studies, laser diagnostics, and chemical kinetics (open access)

Combustion Research Program: Flame studies, laser diagnostics, and chemical kinetics

We have made a detailed study of the care that must be taken to correctly measure OH radical concentrations in flames. A large part of these studies has concerned collisional quenching of hydride radical species (OH, NH, and NH{sub 2}), in particular the dependence upon rotational level and collision velocity (temperature). The results on OH and NH have shown unique and interesting behavior from the viewpoint of fundamental molecular dynamics, pointing to quenching often governed by collisions on an anisotropic, attractive surface, whereas NH{sub 2} quenching appears to depend on state-mixing considerations, not dynamic control. This state-specific behavior of these small, theoretically tractable hydrides has direct ramifications for quantitative flame diagnostics. Our other effort in the diagnostic area has been repeated but unsuccessful searches for laser induced fluorescence in the vinyl radical.
Date: January 22, 1991
Creator: Crosley, D.R.
Object Type: Report
System: The UNT Digital Library
Tenth workshop on geothermal reservoir engineering: proceedings (open access)

Tenth workshop on geothermal reservoir engineering: proceedings

The workshop contains presentations in the following areas: (1) reservoir engineering research; (2) field development; (3) vapor-dominated systems; (4) the Geysers thermal area; (5) well test analysis; (6) production engineering; (7) reservoir evaluation; (8) geochemistry and injection; (9) numerical simulation; and (10) reservoir physics. (ACR)
Date: January 22, 1985
Creator: unknown
Object Type: Article
System: The UNT Digital Library
Fundamental studies of catalytic processing of synthetic liquids (open access)

Fundamental studies of catalytic processing of synthetic liquids

This project revolves around understanding the fundamental processes involved in the catalytic removal of harmful oxygenated organics present in coal liquids. We are modelling the complex type of sulfided Mo catalyst proposed for these reactions with simple single crystal surfaces. These display a controlled range and number of reaction sites and can be extensively characterized by surface science techniques. We then investigate the reaction pathways for representative simple oxygenates upon these surfaces.
Date: January 22, 1992
Creator: Watson, P. R.
Object Type: Report
System: The UNT Digital Library
A high-throughput contact-hole resolution metric for photoresists:Full-process sensitivity study (open access)

A high-throughput contact-hole resolution metric for photoresists:Full-process sensitivity study

The ability to accurately quantify the intrinsic resolution of chemically amplified photoresists is critical for the optimization of resists for extreme ultraviolet (EUV) Iithography. We have recently reported on two resolution metrics that have been shown to extract resolution numbers consistent with direct observation. In this paper we examine the previously reported contact-hole resolution metric and explore the sensitivity of the metric to potential error sources associated with the experimental side of the resolution extraction process. For EUV exposures at the SEMATECH Berkeley microfield exposure tool, we report a full-process error-bar in extracted resolution of 1.75 nm RMS and verify this result experimentally.
Date: January 22, 2008
Creator: Anderson, Christopher N. & Naulleau, Patrick P.
Object Type: Article
System: The UNT Digital Library
TANK FARM RETRIEVAL LESSONS LEARNED AT THE HANFORD SITE (open access)

TANK FARM RETRIEVAL LESSONS LEARNED AT THE HANFORD SITE

One of the environmental remediation challenges facing the nation is the retrieval and permanent disposal of approximately 90 million gallons of radioactive waste stored in underground tanks at the U. S. Department of Energy (DOE) facilities. The Hanford Site is located in southeastern Washington State and stores roughly 60 percent of this waste. An estimated 53 million gallons of high-level, transuranic, and low-level radioactive waste is stored underground in 149 single-shell tanks (SSTs) and 28 newer double-shell tanks (DSTs) at the Hanford Site. These SSTs range in size from 55,000 gallons to 1,000,000 gallon capacity. Approximately 30 million gallons of this waste is stored in SSTs. The SSTs were constructed between 1943 and 1964 and all have exceeded the nominal 20-year design life. Sixty-seven SSTs are known or suspected to have leaked an estimated 1,000,000 gallons of waste to the surrounding soil. The risk of additional SST leakage has been greatly reduced by removing more than 3 million gallons of interstitial liquids and supernatant and transferring this waste to the DST system. Retrieval of SST saltcake and sludge waste is underway to further reduce risks and stage feed materials for the Hanford Site Waste Treatment Plant. Regulatory requirements for SST …
Date: January 22, 2008
Creator: RA, DODD
Object Type: Article
System: The UNT Digital Library
ENVIRONMENTAL SAMPLING AND ANALYSIS - GETTING IT RIGHT (open access)

ENVIRONMENTAL SAMPLING AND ANALYSIS - GETTING IT RIGHT

The Department of Energy's Hanford Site in southeastern Washington State was established in the 1940s as part of the Manhattan Project. Hanford's role was to produce weapons-grade nuclear material for defense, and by 1989, when the Site's mission changed from operations to cleanup, Hanford had produced more than 60 percent of the nation's plutonium. The legacy of Hanford's production years is enormous in terms of nuclear and hazardous waste, especially the 270 billion gallons of contaminated groundwater and the 5 million cubic yards of contaminated soil. Managing the contaminated soil and groundwater are particularly important because the Columbia River, the lifeblood of the northwest and the nation's eighth largest river, bounds the Site. Fluor Hanford's Soil & Groundwater Remediation Project (S&GRP) integrates all of the activities that deal with remediating and monitoring the groundwater across the Site. The S&GRP uses a detailed series of steps to record, track, and verify information. The Sample and Data Management (SDM) Process consists of 10 integrated steps that start with the data quality objectives process that establishes the mechanism for collecting the right information with the right people. The process ends with data quality assessment, which is used to ensure that all quantitative data …
Date: January 22, 2008
Creator: CW, CONNELL
Object Type: Article
System: The UNT Digital Library
Science & Technology Review March/April 2008 (open access)

Science & Technology Review March/April 2008

This month's issue has the following articles: (1) Science and Security in Sharp Focus--Commentary by William H. Goldstein; (2) Extending the Search for Extrasolar Planets--The Gemini Planet Imager will delve deep into the universe to identify planets that cannot be detected with current instrumentation; (3) Standardizing the Art of Electron-Beam Welding--The Laboratory's EBeam Profiler makes electron-beam welds consistent and improves quality control; (4) Molecular Building Blocks Made of Diamonds--Livermore physicists are exploring the electrical properties of diamondoids, tiny molecules of diamond; and (5) Animation Brings Science to Life--Animation helps scientists and engineers effectively communicate their ideas and research in a visually compelling way.
Date: January 22, 2008
Creator: Chinn, D J
Object Type: Report
System: The UNT Digital Library
DEVELOPMENT OF AN IMPROVED SODIUM TITANATE FOR THE PRETREATMENT OF NUCLEAR WASTE AT THE SAVANNAH RIVER SITE (open access)

DEVELOPMENT OF AN IMPROVED SODIUM TITANATE FOR THE PRETREATMENT OF NUCLEAR WASTE AT THE SAVANNAH RIVER SITE

High-level nuclear waste produced from fuel reprocessing operations at the Savannah River Site (SRS) requires pretreatment to remove Cs-137, Sr-90 and alpha-emitting radionuclides (i.e., actinides) prior to disposal onsite as low level waste. Separation processes planned at SRS include sorption of Sr-90 and alpha-emitting radionuclides onto monosodium titanate (MST) and caustic side solvent extraction, for Cs-137 removal. The MST and separated Cs-137 will be encapsulated into a borosilicate glass waste form for eventual entombment at the federal repository. The predominant alpha-emitting radionuclides in the highly alkaline waste solutions include plutonium isotopes Pu-238, Pu-239 and Pu-240. This paper describes recent results to produce an improved sodium titanate material that exhibits increased removal kinetics and capacity for Sr-90 and alpha-emitting radionuclides compared to the baseline MST material.
Date: January 22, 2008
Creator: Hobbs, D
Object Type: Article
System: The UNT Digital Library
PROGRESS IN HANFORDS DOUBLE SHELL TANK (DST) INTEGRITY PROJECT (open access)

PROGRESS IN HANFORDS DOUBLE SHELL TANK (DST) INTEGRITY PROJECT

The U.S. Department of Energy's Office of River Protection has an extensive integrity assessment program for the Hanford Site Double-Shell Tank System. The DOE Orders and environmental protection regulations provide the guidelines for the activities used to inspect and maintain 28 double-shell tanks (DSTs), the waste evaporator, and ancillary equipment that compose this system. This program has been reviewed by oversight and regulatory bodies and found to comply with the established guidelines. The basis for the DOE Order 435.1-1 for tank integrity comes from the Tank Structural Integrity Paneled by Brookhaven National Laboratory during the late 1990s. These guidelines established criteria for performing Non-Destructive Examination (NDE), for acceptance of the NDE results, for waste chemistry control, and for monitoring the tanks. The environmental regulations mirror these requirements and allow for the tank integrity program to provide compliant storage of the tanks. Both sets of requirements provide additional guidance for the protection of ancillary equipment. CH2M HILL uses two methods of NDE: visual inspection and Ultrasonic Testing (UT). The visual inspection program examines the primary tank and secondary liner of the DST. The primary tank is examined both on the interior surface above the waste in the tank and on the …
Date: January 22, 2008
Creator: HS, BERMAN
Object Type: Article
System: The UNT Digital Library
DEEP VADOSE ZONE CONTAMINATION DUE TO RELEASES FROM HANFORD SITE TANKS (open access)

DEEP VADOSE ZONE CONTAMINATION DUE TO RELEASES FROM HANFORD SITE TANKS

CH2M HILL Hanford Group, Inc. (the Hanford Tank Farm Operations contractor) and the Department of Energy's Office of River Protection have just completed the first phase of the Hanford Single-Shell Tank RCRA Corrective Action Program. The focus of this first phase was to characterize the nature and extent of past Hanford single-shell tank releases and to characterize the resulting fate and transport of the released contaminants. Most of these plumes are below 20 meters, with some reaching groundwater (at 60 to 120 meters below ground surface [bgs]).
Date: January 22, 2008
Creator: MN, JARAYSI
Object Type: Article
System: The UNT Digital Library
REINVESTIGATING THE PROCESS IMPACTS FROM OXALIC ACIDHIGH LEVEL WASTE TANK CLEANING (open access)

REINVESTIGATING THE PROCESS IMPACTS FROM OXALIC ACIDHIGH LEVEL WASTE TANK CLEANING

The impacts and acceptability of using oxalic acid to clean the Savannah River Site, High Level Waste Tanks 1-8, were re-investigated using a two-phased approach. For the first phase, using a representative Tank 1-8 sludge, the chemical equilibrium based software, OLI ESP{copyright} and Savannah River Site laboratory test results were used to develop a chemically speciated material balance and a general oxalate mass balance. Using 8 wt% oxalic acid with a 100% molar excess, for every 1 kg of sludge solid that was dissolved, about 3.4 kg of resultant solids would form for eventual vitrification, while about 0.6 kg of soluble oxalate would precipitate in the evaporator system, and form a salt heel. Using available analyses, a list of potential safety and process impacts were developed, screened, and evaluated for acceptability. The results showed that the use of oxalic acid had two distinct types of impacts, those which were safety based and required potential upgrades or additional studies. Assuming such were performed and adequate, no further actions were required. The second type of impacts were also acceptable, but were long-term, and as such, would need to be managed. These impacts were directly caused by the solubility characteristics of oxalate in …
Date: January 22, 2008
Creator: Ketusky, E
Object Type: Article
System: The UNT Digital Library
Tau Decays at BaBar (open access)

Tau Decays at BaBar

Recent results of tau lepton decay studies based on luminosities between 350 fb{sup -1} and 469 fb{sup -1} collected with the BABAR detector at the PEP-II e{sup +}e{sup -} collider at the SLAC National Accelerator Laboratory are presented. The analyses reported here are Charged Current Lepton Universality and 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}}, and K{sup -}{nu}{sub {tau}} decays, as well as searches for Second Class Currents in {tau}{sup -} {yields} {omega}{pi}{sup -}{nu}{sub {tau}} decays, studies of Lepton Flavor Violations, and a tau mass measurement and CPT-Test. If not explicitly mentioned, charge conjugate decay modes are also implied. decays, as well as searches for Second Class Currents in {tau}{sup -} {yields} {omega}{pi}{sup -}{nu}{sub {tau}} decays, studies of Lepton Flavor Violations, and a tau mass measurement and CPT-Test. If not explicitly mentioned, charge conjugate decay modes are also implied.
Date: January 22, 2009
Creator: Hast, Carsten
Object Type: Article
System: The UNT Digital Library
Esmeralda Energy Company Final Scientific Technical Report, January 2008, Emigrant Slimhole Drilling Project, DOE GRED III (DE-FC36-04GO14339) (open access)

Esmeralda Energy Company Final Scientific Technical Report, January 2008, Emigrant Slimhole Drilling Project, DOE GRED III (DE-FC36-04GO14339)

The Emigrant Slimhole Drilling Project (“ESDP”) was a highly successful, phased resource evaluation program designed to evaluate the commercial geothermal potential of the eastern margin of the northern Fish Lake Valley pull-apart basin in west-central Nevada. The program involved three phases: (1) Resource evaluation; (2) Drilling and resource characterization; and (3) Resource testing and assessment. Efforts included detailed geologic mapping; 3-D modeling; compilation of a GIS database; and production of a conceptual geologic model followed by the successful drilling of the 2,938 foot deep 17-31 slimhole (core hole), which encountered commercial geothermal temperatures (327⁰ F) and exhibits an increasing, conductive, temperature gradient to total depth; completion of a short injection test; and compilation of a detailed geologic core log and revised geologic cross-sections. Results of the project greatly increased the understanding of the geologic model controlling the Emigrant geothermal resource. Information gained from the 17-31 core hole revealed the existence of commercial temperatures beneath the area in the Silver Peak Core Complex which is composed of formations that exhibit excellent reservoir characteristics. Knowledge gained from the ESDP may lead to the development of a new commercial geothermal field in Nevada. Completion of the 17-31 core hole also demonstrated the cost-effectiveness …
Date: January 22, 2008
Creator: Deymonaz, John; Hulen, Jeffrey G.; Nash, Gregory D. & Schreiner, Alex
Object Type: Report
System: The UNT Digital Library
Preliminary Field Evaluation of Mercury Control Using Combustion Modifications (open access)

Preliminary Field Evaluation of Mercury Control Using Combustion Modifications

In this project EER conducted a preliminary field evaluation of the integrated approach for mercury (Hg) and NO{sub x} control. The approach enhanced the 'naturally occurring' Hg capture by fly ash through combustion optimization, increasing carbon in ash content, and lowering ESP temperature. The evaluation took place in Green Station Units 1 and 2 located near Henderson, Kentucky and operated by Western Kentucky Energy. Units 1 and 2 are equipped with cold-side ESPs and wet scrubbers. Green Station Units 1 and 2 typically fire two types of fuel: a bituminous coal and a blend of bituminous coals based on availability. Testing of Hg emissions in Unit 2 without reburning system in operation and at minimum OFA demonstrated that efficiencies of Hg reduction downstream of the ESP were 30-40%. Testing also demonstrated that OFA system operation at 22% air resulted in 10% incremental increase in Hg removal efficiency at the ESP outlet. About 80% of Hg in flue gas at ESP outlet was present in the oxidized form. Testing of Hg emissions under reburning conditions showed that Hg emissions decreased with LOI increase and ESP temperature decrease. Testing demonstrated that maximum Hg reduction downstream of ESP was 40-45% at ESP temperatures …
Date: January 22, 2005
Creator: Lissianski, V.; Maly, P. & Marquez, T.
Object Type: Report
System: The UNT Digital Library
Study of low-lying resonant states in 16F using an 15O radioactiveion beam (open access)

Study of low-lying resonant states in 16F using an 15O radioactiveion beam

A 120 MeV {sup 15}O radioactive ion beam with an intensity on target of 4.5 x 10{sup 4} pps has been developed at the 88-inch cyclotron at the Lawrence Berkeley National Laboratory. This beam has been used to study the level structure of {sup 16}F at low energies via the p({sup 15}O,p) reaction using the thick target inverse kinematics method on a polyethylene target. The experimental excitation function was analyzed using R-matrix calculations. Significantly improved values for the level widths of the four low-lying states in 16F are reported. Good agreement with the theoretical spectroscopic factors is also obtained.
Date: January 22, 2007
Creator: Lee, D. W.; Perajarvi, K.; Powell, J.; O'Neil, J. P.; Moltz, D. M.; Goldberg, V. Z. et al.
Object Type: Article
System: The UNT Digital Library
Review of Understanding the Micro to Macro Behaviour of Rock FluidSystems (open access)

Review of Understanding the Micro to Macro Behaviour of Rock FluidSystems

The book consists of a series of summaries of studies supported by the Natural Environmental Research Council's thematic program of the same name. The objective of this research initiative was to improve understanding and characterization of subsurface fluid flow over a wide range of spatial scales through field investigations, laboratory studies, and computer simulations of these processes.
Date: January 22, 2007
Creator: Cortis, A.; Dobson, P. F. & Liu, H. H.
Object Type: Article
System: The UNT Digital Library
CALIBRATION OF THE HB LINE ACTIVE WELL NEUTRON COINCIDENCE COUNTER FOR MEASUREMENT OF LANL 3013 HIGHLY ENRICHED URANIUM PRODUCT SPLITS (open access)

CALIBRATION OF THE HB LINE ACTIVE WELL NEUTRON COINCIDENCE COUNTER FOR MEASUREMENT OF LANL 3013 HIGHLY ENRICHED URANIUM PRODUCT SPLITS

In this paper we describe set-up, calibration, and testing of the F-Area Analytical Labs active well neutron coincidence counter(HV-221000-NDA-X-1-DK-AWCC-1)in SRNL for use in HB-Line to enable assay of 3013EU/Pu metal product. The instrument was required within a three-month window for availability upon receipt of LANL Category IV uranium oxide samples into the SRS HB-Line facility. We describe calibration of the instrument in the SRNL nuclear nondestructive assay facility in the range 10-400 g HEU for qualification and installation in HB-Line for assay of the initial suite of product samples.
Date: January 22, 2008
Creator: Dewberry, R; Donald02 Williams, D; Rstephen Lee, R; David-W Roberts, D & Leah Arrigo, L
Object Type: Article
System: The UNT Digital Library
Weldability of High Alloys (open access)

Weldability of High Alloys

The purpose of this study was to investigate the effect of silicon and iron on the weldability of HAYNES HR-160{reg_sign} alloy. HR-I60 alloy is a solid solution strengthened Ni-Co-Cr-Si alloy. The alloy is designed to resist corrosion in sulfidizing and other aggressive high temperature environments. Silicon is added ({approx}2.75%) to promote the formation of a protective oxide scale in environments with low oxygen activity. HR-160 alloy has found applications in waste incinerators, calciners, pulp and paper recovery boilers, coal gasification systems, and fluidized bed combustion systems. HR-160 alloy has been successfully used in a wide range of welded applications. However, the alloy can be susceptible to solidification cracking under conditions of severe restraint. A previous study by DuPont, et al. [1] showed that silicon promoted solidification cracking in the commercial alloy. In earlier work conducted at Haynes, and also from published work by DuPont et al., it was recognized that silicon segregates to the terminal liquid, creating low melting point liquid films on solidification grain boundaries. Solidification cracking has been encountered when using the alloy as a weld overlay on steel, and when joining HR-160 plate in a thickness greater than19 millimeters (0.75 inches) with matching filler metal. The effect …
Date: January 22, 2003
Creator: Maroef, I
Object Type: Report
System: The UNT Digital Library
Revising the worksheet with L3: a language and environment foruser-script interaction (open access)

Revising the worksheet with L3: a language and environment foruser-script interaction

This paper describes a novel approach to the parameter anddata handling issues commonly found in experimental scientific computingand scripting in general. The approach is based on the familiarcombination of scripting language and user interface, but using alanguage expressly designed for user interaction and convenience. The L3language combines programming facilities of procedural and functionallanguages with the persistence and need-based evaluation of data flowlanguages. It is implemented in Python, has access to all Pythonlibraries, and retains almost complete source code compatibility to allowsimple movement of code between the languages. The worksheet interfaceuses metadata produced by L3 to provide selection of values through thescriptit self and allow users to dynamically evolve scripts withoutre-running the prior versions. Scripts can be edited via text editors ormanipulated as structures on a drawing canvas. Computed values are validscripts and can be used further in other scripts via simplecopy-and-paste operations. The implementation is freely available underan open-source license.
Date: January 22, 2008
Creator: Hohn, Michael H.
Object Type: Article
System: The UNT Digital Library
2006 XSD Scientific Software Workshop report. (open access)

2006 XSD Scientific Software Workshop report.

In May of 2006, a committee was formed to assess the fundamental needs and opportunities in scientific software for x-ray data reduction, analysis, modeling, and simulation. This committee held a series of discussions throughout the summer, conducted a poll of the members of the x-ray community, and held a workshop. This report details the findings and recommendations of the committee. Each experiment performed at the APS requires three crucial ingredients: the powerful x-ray source, an optimized instrument to perform measurements, and computer software to acquire, visualize, and analyze the experimental observations. While the APS has invested significant resources in the accelerator, investment in other areas such as scientific software for data analysis and visualization has lagged behind. This has led to the adoption of a wide variety of software with variable levels of usability. In order to maximize the scientific output of the APS, it is essential to support the broad development of real-time analysis and data visualization software. As scientists attack problems of increasing sophistication and deal with larger and more complex data sets, software is playing an ever more important role. Furthermore, our need for excellent and flexible scientific software can only be expected to increase, as the …
Date: January 22, 2006
Creator: Evans, K., Jr.; De Carlo, F.; Jemian, P.; Lang, J.; Lienert, U.; Maclean, J. et al.
Object Type: Report
System: The UNT Digital Library
Quantum molecular dynamics simulations of uranium at high pressure and temperature (open access)

Quantum molecular dynamics simulations of uranium at high pressure and temperature

Constant-volume quantum molecular dynamics (QMD) simulations of uranium (U) have been carried out over a range of pressures and temperatures that span the experimentally observed solid orthorhombic {alpha}-U, body-centered cubic (bcc), and liquid phases, using an ab initio plane-wave pseudopotential method within the generalized gradient approximation of density functional theory. A robust U pseudopotential has been constructed for these simulations that treats the 14 valence and outer-core electrons per atom necessary to calculate accurate structural and thermodynamic properties up to 100 GPa. Its validity has been checked by comparing low-temperature results with experimental data and all-electron full-potential linear-muffin-tin-orbital calculations of several different uranium solid structures. Calculated QMD energies and pressures for the equation of state of uranium in the solid and liquid phases are given, along with results for the Grueneisen parameter and the specific heat. We also present results for the radial distribution function, bond-angle distribution function, electronic density of states, and liquid diffusion coefficient, as well as evidence for short-range order in the liquid.
Date: January 22, 2008
Creator: Hood, R Q; Yang, L H & Moriarty, J A
Object Type: Article
System: The UNT Digital Library
Drell-Yan Lepton Pair Azimuthal Asymmetry in Hadronic Processes (open access)

Drell-Yan Lepton Pair Azimuthal Asymmetry in Hadronic Processes

We study the azimuthal asymmetry in the Drell-Yan lepton pair production in hadronic scattering processes at moderate transverse momentum region, taking into account the contributions from the twist-three quark-gluon correlations from the unpolarized hadrons. The contributions are found to dominate the asymmetry, and are not power suppressed by qt/Q at small qt where qt and Q are the transverse momentum and invariant mass of the lepton pair. Accordingly, the Lam-Tung relation will be violated at this momentum region, and its violation depends on the twist-three functions. However, at large transverse momentum qt~;;Q, the Lam-Tung relation still holds because all corrections are power suppressed by Lambda2/qt2 ~;; Lambda2/Q2 where Lambda is the typical nonperturbative scale.
Date: January 22, 2009
Creator: Zhou, Jian; Yuan, Feng & Liang, Zuo-Tang
Object Type: Article
System: The UNT Digital Library