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THE FUTURE OF SPIN PHYSICS AT BNL. (open access)

THE FUTURE OF SPIN PHYSICS AT BNL.

The Relativistic Heavy Ion Collider (RHIC) at BNL is the world's only polarized proton-proton collider. Collisions at center-of-mass energies up to 500 GeV and beam polarizations approaching 70% (longitudinal or transverse) are provided to two experiments, STAR and PHENIX, at luminosities {ge} 10{sup 32}/cm{sup 2}/sec. Transverse polarized beam has also been provided to the BRAHMS experiment. Measurements that bear on the important question of the spin content of the nucleon are beginning to appear. Over the next 10 years, as the performance of polarized proton running at RHIC is further developed, the Spin Physics program at RHIC will provide definitive measurements of the contributions to the proton's spin of the gluon, the sea quarks and the orbital motion of the partons in the proton's wave function. We plan to extend the reach of our study of the role of spin in QCD with the development of ''eRHIC'', which will provide polarized e-p collisions to a new detector.
Date: October 2, 2006
Creator: ARONSON, S. & DESHPANDE, A.
System: The UNT Digital Library
Jet Mass and Substructure of Inclusive Jets in $\sqrt{s}=7$ TeV $Pp$ Collisions with the ATLAS Experiment (open access)

Jet Mass and Substructure of Inclusive Jets in $\sqrt{s}=7$ TeV $Pp$ Collisions with the ATLAS Experiment

None
Date: April 2, 2013
Creator: Aad, Georges
System: The UNT Digital Library
Search for New Bottomlike Quark Pair Decays Q Q-Bar to (T W- ) (T-Bar W -) in Same-Charge Dilepton Events (open access)

Search for New Bottomlike Quark Pair Decays Q Q-Bar to (T W- ) (T-Bar W -) in Same-Charge Dilepton Events

We report the most restrictive direct limits on masses of fourth-generation down-type quarks b{prime}, and quark-like composite fermions (B or T{sub 5/3}), decaying promptly to tW{sup {-+}}. We search for a significant excess of events with two same-charge leptons (e, {mu}), several hadronic jets, and missing transverse energy. An analysis of data from p{bar p} collisions with an integrated luminosity of 2.7 fb{sup -1} collected with the CDF II detector at Fermilab yields no evidence for such a signal, setting mass limits m{sub b{prime}}, m{sub B} > 338 GeV/c{sup 2} and m{sub T{sub 5/3}} > 365 GeV/c{sup 2} at 95% confidence level.
Date: April 2, 2012
Creator: Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
System: The UNT Digital Library
Fermi LAT Observations of LS I +61 303: First Detection of an Orbital Modulation in GeV Gamma Rays (open access)

Fermi LAT Observations of LS I +61 303: First Detection of an Orbital Modulation in GeV Gamma Rays

This Letter presents the first results from the observations of LS I +61{sup o}303 using Large Area Telescope data from the Fermi Gamma-Ray Space Telescope between 2008 August and 2009 March. Our results indicate variability that is consistent with the binary period, with the emission being modulated at 26.6 {+-} 0.5 days. This constitutes the first detection of orbital periodicity in high-energy gamma rays (20 MeV-100 GeV, HE). The light curve is characterized by a broad peak after periastron, as well as a smaller peak just before apastron. The spectrum is best represented by a power law with an exponential cutoff, yielding an overall flux above 100 MeV of 0.82 {+-} 0.03(stat) {+-} 0.07(syst) 10{sup -6} ph cm{sup -2} s{sup -1}, with a cutoff at 6.3 {+-} 1.1(stat) {+-} 0.4(syst) GeV and photon index {Gamma} = 2.21 {+-} 0.04(stat) {+-} 0.06(syst). There is no significant spectral change with orbital phase. The phase of maximum emission, close to periastron, hints at inverse Compton scattering as the main radiation mechanism. However, previous very high-energy gamma ray (>100 GeV, VHE) observations by MAGIC and VERITAS show peak emission close to apastron. This and the energy cutoff seen with Fermi suggest that the link …
Date: April 2, 2012
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Atwood, W. B.; Axelsson, M.; Baldini, L. et al.
System: The UNT Digital Library
Constraints on Cosmological Dark Matter Annihilation from the Fermi-LAT Isotropic Diffuse Gamma-Ray Measurement (open access)

Constraints on Cosmological Dark Matter Annihilation from the Fermi-LAT Isotropic Diffuse Gamma-Ray Measurement

None
Date: July 2, 2013
Creator: Abdo, A. A.; Ackermann, M.; Ajello, M.; Baldini, L.; Ballet, J.; Barbiellini, G. et al.
System: The UNT Digital Library
Effective and efficient optics inspection approach using machine learning algorithms (open access)

Effective and efficient optics inspection approach using machine learning algorithms

The Final Optics Damage Inspection (FODI) system automatically acquires and utilizes the Optics Inspection (OI) system to analyze images of the final optics at the National Ignition Facility (NIF). During each inspection cycle up to 1000 images acquired by FODI are examined by OI to identify and track damage sites on the optics. The process of tracking growing damage sites on the surface of an optic can be made more effective by identifying and removing signals associated with debris or reflections. The manual process to filter these false sites is daunting and time consuming. In this paper we discuss the use of machine learning tools and data mining techniques to help with this task. We describe the process to prepare a data set that can be used for training and identifying hardware reflections in the image data. In order to collect training data, the images are first automatically acquired and analyzed with existing software and then relevant features such as spatial, physical and luminosity measures are extracted for each site. A subset of these sites is 'truthed' or manually assigned a class to create training data. A supervised classification algorithm is used to test if the features can predict the …
Date: November 2, 2010
Creator: Abdulla, G.; Kegelmeyer, L.; Liao, Z. & Carr, W.
System: The UNT Digital Library
Global polarization measurement in Au+Au collisions (open access)

Global polarization measurement in Au+Au collisions

The system created in non-central relativisticnucleus-nucleus collisions possesses large orbital angular momentum. Dueto spin-orbit coupling, particles produced in such a system could becomeglobally polarized along the direction of the system angular momentum. Wepresent the results of Lambda and anti-Lambda hyperon global polarizationmeasurements in Au+Au collisions at sqrt sNN=62.4 GeV and 200 GeVperformed with the STAR detector at RHIC. The observed globalpolarization of Lambda and anti-Lambda hyperons in the STAR acceptance isconsistent with zero within the precision of the measurements. Theobtained upper limit, lbar P Lambda, anti-Lambda rbar<= 0.02, iscompared to the theoretical values discussed recently in theliterature.
Date: August 2, 2007
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
Measurement of Transverse Single-Spin Asymmetries for Di-JetProduction in Proton-Proton Collisions at sqrt s = 200 GeV (open access)

Measurement of Transverse Single-Spin Asymmetries for Di-JetProduction in Proton-Proton Collisions at sqrt s = 200 GeV

We report the first measurement of the opening angledistribution between pairs of jets produced in high-energy collisions oftransversely polarized protons. The measurement probes (Sivers)correlations between the transverse spin orientation of a proton and thetransverse momentum directions of its partons. With both beams polarized,the wide pseudorapidity (-1 leq eta leq +2) coverage for jets permitsseparation of Sivers functions for the valence and sea regions. Theresulting asymmetries are all consistent with zero and considerablysmaller than Sivers effects observed in semi-inclusive deep inelasticscattering (SIDIS). We discuss theoretical attempts to reconcile the newresults with the sizable transverse spin effects seen in SIDIS andforward hadron production in pp collisions.
Date: October 2, 2007
Creator: Abelev, B. I.; Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
Inductively Coupled Plasma Etching of III-V Semiconductors in BCl(3)-Based Chemistries: Part II: InP, InGaAs, InGaAsP, InAs and AllnAs (open access)

Inductively Coupled Plasma Etching of III-V Semiconductors in BCl(3)-Based Chemistries: Part II: InP, InGaAs, InGaAsP, InAs and AllnAs

A parametric study of etch rates and surface morphologies of In-containing compound semiconductors (InP, InGaAs, InGaAsP, InAs and AlInAs) obtained by BClj-based Inductively Coupled Plasmas is reported. Etch rates in the range 1,500-3,000 &min. are obtained for all the materials at moderate source powers (500 W), with the rates being a strong function of discharge composition, rf chuck power and pressure. Typical root-mean-square surface roughness of-5 nm were obtained for InP, which is worse than the values obtained for Ga-based materials under the same conditions (-1 run). The near surface of etched samples is typically slightly deficient in the group V element, but the depth of this deficiency is small (a few tens of angstroms).
Date: December 2, 1998
Creator: Abernathy, C.R.; Han, J.; Hobson, W.S.; Hong, J.; Lambers, E.S.; Lee, J.W. et al.
System: The UNT Digital Library
New Correction Procedure for X-Ray Spectroscopic Fluorescence Data: Simulations and Experiment. (open access)

New Correction Procedure for X-Ray Spectroscopic Fluorescence Data: Simulations and Experiment.

X-ray fluorescence spectroscopy is a widely used method for determining the electronic configuration and local structure of dilute species with high sensitivity. In the dilute limit, and for thin films, the X-ray fluorescence signal is directly proportional to the atomic sub-shell absorption coefficient. However, for concentrated samples, the well-documented self-absorption effect often leads to the severe suppression of XANES (X-ray Absorption Near-Edge Structure) and EXAFS (Extended X-ray Absorption Fine-Structure) amplitudes. Thus to recover the real value of the sub-shell absorption coefficient, it is important to apply correction procedures to the measured fluorescence spectra. In this paper, we describe a new straightforward method to correct for self-absorption effects (the difference in the measured fluorescence signal compared to that of the true sub-shell photoabsorption coefficient) in XANES and EXAFS fluorescence measurements. Using a variety of sample and detector configurations, this method is used to extract the sub-shell absorption coefficient on elemental nickel and thick single-crystals of Gd{sub 3}Ga{sub 5}O{sub 12} and LaAlO{sub 3}.
Date: August 2, 2004
Creator: Ablett, J. M.; Woicik, J. C. & Kao, C. C.
System: The UNT Digital Library
Hydrogen Safety Training for Researchers and Technical Personnel (open access)

Hydrogen Safety Training for Researchers and Technical Personnel

None
Date: December 2, 2011
Creator: Aceves, S. M.; Espinosa-Loza, F.; Petitpas, G.; Ross, T. O. & Switzer, V. A.
System: The UNT Digital Library
Genomics-based selection and functional characterization of triterpene glycosyltransferases from the model legume Medicago truncatula (open access)

Genomics-based selection and functional characterization of triterpene glycosyltransferases from the model legume Medicago truncatula

Article on genomics-based selection and functional characterization of triterpene glycosyltransferases from the model legume Medicago truncatula.
Date: February 2, 2005
Creator: Achnine, Lahoucine; Huhman, David; Farag, Mohamed A.; Sumner, Lloyd W.; Blount, Jack W. & Dixon, R. A.
System: The UNT Digital Library
Cation distribution in a Fe-bearing K-feldspar from Itrongay,Madagascar. A combined neutron- and X-ray single crystal diffractionstudy (open access)

Cation distribution in a Fe-bearing K-feldspar from Itrongay,Madagascar. A combined neutron- and X-ray single crystal diffractionstudy

We determined the cation distribution and ordering of Si, Al and Fe on the tetrahedral sites of a monoclinic low-sanidine from Itrongay, Madagascar, by combined neutron- and X-ray single-crystal diffraction. The cation distribution was determined by means of a simultaneous refinement using neutron- and X-ray data, as well as by combining scattering densities obtained from separate refinements with chemical data from a microprobe experiment. The two methods give the same results and show that Fe is fully ordered on T1, whereas Al shows a high degree of disorder. Based on this and previously published temperature-dependent X-ray data, we conclude that it is preferential ordering of Fe on T1 even at high temperature, rather than a high diffusion kinetics of Fe, which causes this asymmetry in ordering behavior between Al and Fe. The preferential ordering of Fe3+ relative to Al3+ in T1 is consistent with its 25 percent larger ionic radius.
Date: May 2, 2005
Creator: Ackermann, Sonia; Kunz, Martin; Armbruster, Thomas; Schefer,Jurg & Hanni, Henry
System: The UNT Digital Library

Commentary on "Thermodynamic equilibrium of hydroxyacetic acid in pure and binary solvent systems"

This article discusses published mathematical representations by Huant et al. (2017) for describing how the measured mole fraction solubility varies with solvent composition in the binary (ethanol + ethyl acetate) and binary (acetone + ethanol) solvent systems.
Date: February 2, 2017
Creator: Acree, William E. (William Eugene)
System: The UNT Digital Library
Event-by-event hexb pt hexb fluctuations in Au-Au collisions atsqrt(sNN) = 130 GeV (open access)

Event-by-event hexb pt hexb fluctuations in Au-Au collisions atsqrt(sNN) = 130 GeV

We present the first large-acceptance measurement of event-wise &lt;p{sub t}&gt; fluctuations in Au-Au collisions at {radical}s{sub NN} = 130 GeV. Significant nonstatistical fluctuations are observed. The measured fractional r.m.s. width excess of the event-wise &lt;p{sub t}&gt; distribution for the 15% most-central events for charged hadrons within |{eta}| &lt; 1 and 0.15 {le} p{sub t} {le} 2 GeV/c is 13.7 {+-} 0.1(stat) {+-}1.3(syst)% relative to a statistical reference. The variation of charge-independent fluctuation excess with centrality is non-monotonic but smooth. Charge-dependent nonstatistical fluctuations are also observed.
Date: September 2, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
Transverse-Momentum and Collision Energy Dependence of High p{sub T} Hadron Suppression in Au+Au Collisions at Ultrarelativistic Energies (open access)

Transverse-Momentum and Collision Energy Dependence of High p{sub T} Hadron Suppression in Au+Au Collisions at Ultrarelativistic Energies

No abstract prepared.
Date: September 2, 2003
Creator: Adams, J.; Adler, C.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D. et al.
System: The UNT Digital Library
Measurements of Transverse Energy Distributions in Au+Au Collisions at {radical}s{sub NN} = 200 GeV (open access)

Measurements of Transverse Energy Distributions in Au+Au Collisions at {radical}s{sub NN} = 200 GeV

Transverse energy (E{sub T}) distributions have been measured for Au+Au collisions at {radical}s{sub NN} = 200 GeV by the STAR collaboration at RHIC. E{sub T} is constructed from its hadronic and electromagnetic components, which have been measured separately. E{sub T} production for the most central collisions is well described by several theoretical models whose common feature is large energy density achieved early in the fireball evolution. The magnitude and centrality dependence of E{sub T} per charged particle agrees well with measurements at lower collision energy, indicating that the growth in E{sub T} for larger collision energy results from the growth in particle production. The electromagnetic fraction of the total E{sub T} is consistent with a final state dominated by mesons and independent of centrality.
Date: July 2, 2004
Creator: Adams, J.; Aggarwal, M. M.; Ahammed, Z.; Amonett, J.; Anderson, B. D.; Arkhipkin, D. et al.
System: The UNT Digital Library
MOBILE SYSTEMS FOR DILUTION OF HIGHLY ENRICHED URANIUM AND URANIUM CONTAINING COMPONENTS (open access)

MOBILE SYSTEMS FOR DILUTION OF HIGHLY ENRICHED URANIUM AND URANIUM CONTAINING COMPONENTS

A mobile melt-dilute (MMD) module for the treatment of aluminum research reactor spent fuel is being developed. The process utilizes a closed system approach to retain fission products/gases inside a sealed canister after treatment. The MMD process melts and dilutes spent fuel with depleted uranium to obtain a fissile fraction of less than 0.2. The final ingot is solidified inside the sealed canister and can be stored safely either wet or dry until final disposition or reprocessing. The MMD module can be staged at or near the research reactor fuel storage sites to facilitate the melt-dilute treatment of the spent fuel into a stable non-proliferable form.
Date: May 2, 2007
Creator: Adams, T
System: The UNT Digital Library
Renaissance of the ~ 1-TeV Fixed-Target Program (open access)

Renaissance of the ~ 1-TeV Fixed-Target Program

This document describes the physics potential of a new fixed-target program based on a {approx}1 TeV proton source. Two proton sources are potentially available in the future: the existing Tevatron at Fermilab, which can provide 800 GeV protons for fixed-target physics, and a possible upgrade to the SPS at CERN, called SPS+, which would produce 1 TeV protons on target. In this paper we use an example Tevatron fixed-target program to illustrate the high discovery potential possible in the charm and neutrino sectors. We highlight examples which are either unique to the program or difficult to accomplish at other venues.
Date: December 2, 2011
Creator: Adams, T.; Appel, J. A.; Arms, K. E.; Balantekin, A. B.; Conrad, J. M.; Cooper, P. S. et al.
System: The UNT Digital Library
Characterization of Environmental Stability of Pulsed Laser Deposited Oxide Ceramic Coatings (open access)

Characterization of Environmental Stability of Pulsed Laser Deposited Oxide Ceramic Coatings

A systematic investigation of candidate hydrogen permeation materials applied to a substrate using Pulsed Laser Deposition has been performed. The investigation focused on application of leading permeation-resistant materials types (oxide, carbides, and metals) on a stainless steel substrate. and evaluation of the stability of the applied coatings. Type 304L stainless steel substrates were coated with aluminum oxide, chromium oxide, and aluminum. Characterization of the coating-substrate system adhesion was performed using scratch adhesion testing and microindentation. Coating stability and environmental susceptibility were evaluated for two conditions-air at 350 degrees Celsius and Ar-H2 at 350 degrees Celsius for up to 100 hours. Results from this study have shown the pulsed laser deposition process to be an extremely versatile technology that is capable of producing a sound coating/substrate system for a wide variety of coating materials.
Date: March 2, 2004
Creator: Adams, Thad M.
System: The UNT Digital Library
MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on Angular Scales of 10' to 5 Degrees (open access)

MAXIMA-1: A Measurement of the Cosmic Microwave Background Anisotropy on Angular Scales of 10' to 5 Degrees

We present a map and an angular power spectrum of the anisotropy of the cosmic microwave background (CMB) from the first flight of MAXIMA. MAXIMA is a balloon-borne experiment with an array of 16 bolometric photometers operated at 100 mK. MAXIMA observed a 124 deg region of the sky with 10' resolution at frequencies of 150, 240 and 410 GHz. The data were calibrated using in-flight measurements of the CMB dipole anisotropy. A map of the CMB anisotropy was produced from three 150 and one 240 GHz photometer without need for foreground subtractions. Analysis of this CMB map yields a power spectrum for the CMB anisotropy over the range 36 {le} {ell} {le} 785. The spectrum shows a peak with an amplitude of 78 {+-} 6 {mu}K at {ell} {approx_equal} 220 and an amplitude varying between {approx} 40 {mu}K and {approx} 50 {mu}K for 400 {approx}&lt; {ell} {approx}&lt; 785.
Date: October 2, 2000
Creator: Ade, P.; Balbi, A.; Bock, J.; Borrill, J.; Boscaleri, A.; deBernardis, P. et al.
System: The UNT Digital Library
Evaluation of pathways to the C-glycosyl isoflavone puerarin in roots of kudzu (Pueraria montana lobata) (open access)

Evaluation of pathways to the C-glycosyl isoflavone puerarin in roots of kudzu (Pueraria montana lobata)

Article describes how kudzu produces both O- and C-glycosylated isoflavones, with puerarin (C-glucosyl daidzein) as an important bioactive compound. The authors go on to explain how expression of recombinant UGTs in Escherichia coli and candidate C-glycosyltransferases in Medicago truncatula were used to explore substrate specificities, and gene silencing of UGT and key isoflavone biosynthetic genes in kudzu hairy roots employed to test hypotheses concerning the substrate(s) for C-glycosylation.
Date: September 2, 2022
Creator: Adolfo, Laci M.; Burks, David J.; Rao, Xiaolan; Alvarez-Hernandez, Anislay & Dixon, R. A.
System: The UNT Digital Library
Supersymmetry Parameter Analysis: SPA Convention and Project (open access)

Supersymmetry Parameter Analysis: SPA Convention and Project

High-precision analyses of supersymmetry parameters aim at reconstructing the fundamental supersymmetric theory and its breaking mechanism. A well defined theoretical framework is needed when higher-order corrections are included. We propose such a scheme, Supersymmetry Parameter Analysis SPA, based on a consistent set of conventions and input parameters. A repository for computer programs is provided which connect parameters in different schemes and relate the Lagrangian parameters to physical observables at LHC and high energy e{sup +}e{sup -} linear collider experiments, i.e., masses, mixings, decay widths and production cross sections for supersymmetric particles. In addition, programs for calculating high-precision low energy observables, the density of cold dark matter (CDM) in the universe as well as the cross sections for CDM search experiments are included. The SPA scheme still requires extended efforts on both the theoretical and experimental side before data can be evaluated in the future at the level of the desired precision. We take here an initial step of testing the SPA scheme by applying the techniques involved to a specific supersymmetry reference point.
Date: December 2, 2005
Creator: Aguilar-Saavedra, J. A.; Ali, A.; Allanach, B. C.; Arnowitt, R.; Baer, H. A.; Bagger, J. A. et al.
System: The UNT Digital Library
Characterization and Prediction of Subsurface Pneumatic PressureVariations at Yucca Mountain, Nevada (open access)

Characterization and Prediction of Subsurface Pneumatic PressureVariations at Yucca Mountain, Nevada

Yucca Mountain, Nevada is being investigated as the proposed site for geologic disposal of high level nuclear waste. A massive data collection effort for characterization of the unsaturated zone is being carried out at the site. The USGS is monitoring the subsurface pressure variations due to barometric pumping in several boreholes. Numerical models are used to simulate the observed subsurface pressure variations. Data inversion is used to characterize the unsaturated system and estimate the pneumatic diffusivity of important geologic features. Blind predictions of subsurface response and subsequent comparison to recorded data have built confidence in the models of Yucca Mountain.
Date: January 2, 1998
Creator: Ahlers, C. Fredrik; Finsterle, Stefan & Bodvarsson, Gudmundur S.
System: The UNT Digital Library