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2,586 Matching Results
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Novel Source Ionizer Options for Polarized Ions
N/A
Date:
September 1, 2000
Creator:
A., Hershcovitch
Object Type:
Report
System:
The UNT Digital Library
CW Mode of Operation of a Proton FFAG Accelerator
N/A
Date:
September 1, 2005
Creator:
A., Ruggiero
Object Type:
Report
System:
The UNT Digital Library
RF and structural characterization of new SRF films
In the past years, energetic vacuum deposition methods have been developed in different laboratories to improve Nb/Cu technology for superconducting cavities. Jefferson Lab is pursuing energetic condensation deposition via Electron Cyclotron Resonance. As part of this study, the influence of the deposition energy on the material and RF properties of the Nb thin film is investigated. The film surface and structure analyses are conducted with various techniques like X-ray diffraction, Transmission Electron Microscopy, Auger Electron Spectroscopy and RHEED. The microwave properties of the films are characterized on 50 mm disk samples with a 7.5 GHz surface impedance characterization system. This paper presents surface impedance measurements in correlation with surface and material characterization for Nb films produced on copper substrates with different bias voltages and also highlights emerging opportunities for developing multilayer SRF films with a new deposition system.
Date:
September 1, 2009
Creator:
A.-M. Valente-Feliciano,H. L. Phillips,C. E. Reece,X. Zhao,D. Gu,R. Lukaszew,B. Xiao,K. Seo
Object Type:
Article
System:
The UNT Digital Library
Location Algorithms and Errors in Time-of-Arrival Systems
This report describes least squares solution methods and linearized estimates of solution errors caused by data errors. These methods are applied to event locating systems which use time-of-arrival (TOA) data. Analyses are presented for algorithms that use the TOA data in a ''direct'' manner and for algorithms utilizing Time-of-arrival Squared (TSQ) methods. Location and error estimation results were applied to a ''typical'' satellite TOA detecting system. Using Monte Carlo methods, it was found that the linearized location error estimates were valid for random data errors with relatively large variances and relatively poor event/sensor geometries. In addition to least squares methods, which use an L{sub 2} norm, methods were described for L{sub 1} and L{sub {infinity}} norms. In general, these latter norms offered little improvement over least squares methods. Reduction of the location error variances can be effected by using information in addition to the TOA data themselves by adding judiciously chosen ''conditioning'' equation(s) to the least squares system. However, the added information can adversely affect the mean errors. Also, conditioned systems may offer location solutions where nonconditioned scenarios may not be solvable. Solution methods and linearized error estimates are given for ''conditioned'' systems. It was found that for significant data …
Date:
September 1, 2001
Creator:
AARONSON, EUGENE A.
Object Type:
Report
System:
The UNT Digital Library
MICROHOLE TECHNOLOGY PROGRESS ON BOREHOLE INSTRUMENTATION DEVELOPMENT
Microhole technology development is based on the premise that with advances in electronics and sensors, large conventional-diameter wells are no longer necessary for obtaining subsurface information. Furthermore, microholes offer an environment for improved substance measurement. The combination of deep microholes having diameters of 1-3/8 in. at their terminal depth and 7/8-in. diameter logging tools will comprise a very low cost alternative to currently available technology for deep subsurface characterization and monitoring.
Date:
September 1, 2000
Creator:
ALBRIGHT, J.
Object Type:
Article
System:
The UNT Digital Library
SPALL STUDIES IN COPPER FOILS USING THE LASER-DRIVEN MINIFLYER
None
Date:
September 1, 2000
Creator:
ALEXANDER, D. J.; ROBBINS, D. L. & SHEFFIELD, S. A.
Object Type:
Article
System:
The UNT Digital Library
COSMIC-RAY PRODUCTION OF 6,7Li BY THE ALPHA + ALPHA REACTION
None
Date:
September 1, 2000
Creator:
AUSTIN, S. M. & MERCER, D. J.
Object Type:
Article
System:
The UNT Digital Library
Measurement of Resonance Parameters of Orbitally Excited Narrow B^0 Mesons
The authors report a measurement of resonance parameters of the orbitally excited (L = 1) narrow B{sup 0} mesons in decays to B{sup (*)+}{pi}{sup -} using 1.7 fb{sup -1} of data collected by the CDF II detector at the Fermilab Tevatron. The mass and width of the B*{sub 2}{sup 0} state are measured to be m(B*{sub 2}{sup 0}) = 5740.2{sub -1.8}{sup +1.7}(stat.){sub -0.8}{sup +0.9}(syst.) MeV/c{sup 2} and {Lambda}(B*{sub 2}{sup 0}) = 22.7{sub -3.2}{sup +3.8}(stat.){sub -10.2}{sup +3.2}(syst.) MeV/c{sub 2}. The mass difference between the B*{sub 2}{sup 0} and B{sub 1}{sup 0} states is measured to be 14.9{sub -2.5}{sup +2.2}(stat.){sub -1.4}{sup +1.2}(syst.) MeV/c{sup 2}, resulting in a B{sub 1}{sup 0} mass of 5725.3{sub -2.2}{sup +1.6}(stat.){sub -1.5}{sup +1.4}(syst.) MeV/c{sup 2}. This is currently the most precise measurement of the masses of these states and the first measurement of the B*{sub 2}{sup 0} width.
Date:
September 1, 2008
Creator:
Aaltonen, : T.
Object Type:
Article
System:
The UNT Digital Library
Global Search for New Physics with 2.0 fb88-1 at CDF
Data collected in Run II of the Fermilab Tevatron are searched for indications of new electroweak-scale physics. Rather than focusing on particular new physics scenarios, CDF data are analyzed for discrepancies with the standard model prediction. A model-independent approach (VISTA) considers gross features of the data, and is sensitive to new large cross-section physics. Further sensitivity to new physics is provided by two additional algorithms: a Bump Hunter searches invariant mass distributions for 'bumps' that could indicate resonant production of new particles; and the Sleuth procedure scans for data excesses at large summed transverse momentum. This combined global search for new physics in 2.0 fb{sup -1} of p{bar p} collisions at {radical}s = 1.96 TeV reveals no indication of physics beyond the standard model.
Date:
September 1, 2008
Creator:
Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the Single Top Quark Production Cross Section at CDF
We report a measurement of the single top quark production cross section in 2.2 fb{sup -1} of p{bar p} collision data collected by the Collider Detector at Fermilab at {radical}s = 1.96 TeV. Candidate events are classified as signal-like by three parallel analyses which use likelihood, matrix element, and neural network discriminants. These results are combined in order to improve the sensitivity. We observe a signal consistent with the standard model prediction, but inconsistent with the background only model by 3.7 standard deviations with a median expected sensitivity of 4.9 standard deviations. We measure a cross section of 2.2{sub -0.6}{sup +0.7}(stat+sys) pb, extract the CKM matrix element value |V{sub tb}| = 0.88{sub -0.12}{sup +0.13}(stat + sys) {+-} 0.07(theory), and set the limit |V{sub tb}| > 0.66 at the 95% C.L.
Date:
September 1, 2008
Creator:
Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
Object Type:
Article
System:
The UNT Digital Library
Search for a Higgs Boson Decaying to Two W Bosons at CDF
We present a search for a Higgs boson decaying to two W bosons in p{bar p} collisions at {radical}s = 1.96 TeV center-of-mass energy. The data sample corresponds to an integrated luminosity of 3.0 fb{sup -1} collected with the CDF II detector. We find no evidence for production of a Higgs boson with mass between 110 and 200 GeV/c{sup 2}, and determine upper limits on the production cross section. For the mass of 160 GeV/c{sup 2}, where the analysis is most sensitive, the observed (expected) limit is 0.7 pb (0.9 pb) at 95% Bayesian credibility level which is 1.7 (2.2) times the standard model cross section.
Date:
September 1, 2008
Creator:
Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
Object Type:
Article
System:
The UNT Digital Library
Search for Maximal Flavor Violating Scalars in Same-Charge Lepton Pairs in p anti-p Collisions at s**(1/2) = 1.96-TeV
Models of Maximal Flavor Violation (MxFV) in elementary particle physics may contain at least one new scalar SU(2) doublet field {Phi}{sub FV} = ({eta}{sup 0},{eta}{sup +}) that couples the first and third generation quarks (q{sub 1}; q{sub 3}) via a Lagrangian term L{sub FV} = {zeta}{sub 13}{Phi}{sub FV}q{sub 1}q{sub 3}. These models have a distinctive signature of same-charge top-quark pairs and evade flavor-changing limits from meson mixing measurements. Data corresponding to 2 fb{sup -1} collected by the CDF II detector in p{bar p} collisions at {radical}s = 1.96 TeV are analyzed for evidence of the MxFV signature. For a neutral scalar {eta}{sup 0} with m{sub {eta}{sup 0}} = 200 GeV/c{sup 2} and coupling {zeta}{sub 13} = 1, {approx} 11 signal events are expected over a background of 2.1 {+-} 1.8 events. Three events are observed in the data, consistent with background expectations, and limits are set on the coupling {zeta}{sub 13} for m{sub {eta}{sup 0}} = 180-300 GeV/c{sup 2}.
Date:
September 1, 2008
Creator:
Aaltonen, T.; Adelman, J.; Akimoto, T.; Albrow, Michael G.; Alvarez Gonzalez, B.; Amerio, S. et al.
Object Type:
Article
System:
The UNT Digital Library
The First measurement of the top quark mass at CDF II in the lepton+jets and dilepton channels simultaneously
The authors present a measurement of the mass of the top quark using data corresponding to an integrated luminosity of 1.9 fb{sup -1} of p{bar p} collisions collected at {radical}s = 1.96 TeV with the CDF II detector at Fermilab's Tevatron. This is the first measurement of the top quark mass using top-antitop pair candidate events in the lepton + jets and dilepton decay channels simultaneously. They reconstruct two observables in each channel and use a non-parametric kernel density estimation technique to derive two-dimensional probability density functions from simulated signal and background samples. The observables are the top quark mass and the invariant mass of two jets from the W decay in the lepton + jets channel, and the top quark mass and the scalar sum of transverse energy of the event in the diletpon channel. They perform a simultaneous fit for the top quark mass and the jet energy scale, which is constrained in situ by the hadronic W boson mass. using 332 lepton + jets candidate events and 144 diletpon candidate events, they measure the top quark mass to be m{sub top} = 171.9 {+-} 1.7 (stat. + JES) {+-} 1.1 (other sys.) GeV/c{sup 2} = 171.9 {+-} …
Date:
September 1, 2008
Creator:
Aaltonen, T.; Adelman, J.; Akimoto, T.; U., /Tsukuba; Albrow, Michael G.; Alvarez Gonzalez, B. et al.
Object Type:
Article
System:
The UNT Digital Library
Search for resonant t anti-t production in p anti-p collisions at s**(1/2) = 1.96-TeV
We report on a search for narrow-width particles decaying to a top and antitop quark pair. The data set used in the analysis corresponds to an integrated luminosity of 680 pb{sup -1} collected with the Collider Detector at Fermilab in Run II. We present 95% confidence level upper limits on the cross section times branching ratio. Assuming a specific top color-assisted technicolor production model, the leptophobic Z{prime} with width {Gamma}{sub Z{prime}} = 0.012M{sub Z{prime}}, we exclude the mass range M{sub Z{prime}} < 725 GeV/c{sup 2} at the 95% confidence level.
Date:
September 1, 2007
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Abulencia, A.; /Illinois U., Urbana; Adelman, J.; /Chicago U., EFI et al.
Object Type:
Article
System:
The UNT Digital Library
First Measurement of the b-jet Cross Section in Events with a W Boson in p anti-p Collisions at s**(1/2) = 1.96-TeV
The cross section for jets from b quarks produced simultaneously with a W boson has been measured in p{bar p} collision data from 1.9 fb{sup -1} of integrated luminosity recorded by the CDF II detector at the Tevatron. Jets consistent with the decay of long-lived hadrons are selected by identifying a displaced decay vertex. The invariant mass of the charged particle tracks associated with the vertex is sensitive to the flavor of the decaying hadron and is used to determine the fraction of jets from b-quark production. We measure a b-jet cross section of 2.74 {+-} 0.27(stat.) {+-} 0.42(syst.) pb in association with one flavor of leptonic W boson decay over a limited kinematic phase space.
Date:
September 1, 2009
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Akimoto, T.; U., /Tsukuba et al.
Object Type:
Article
System:
The UNT Digital Library
Direct measurement of the W boson width
We present a direct measurement of the width of the W boson using the shape of the transverse mass distribution of W {yields} e{nu} candidates selected in 1 fb{sup -1} of data collected with the D0 detector at the Fermilab Tevatron collider in p{bar p} collisions at {radical}s = 1.96 TeV. We use the same methods and data sample that were used for our recently published W boson mass measurement, except for the modeling of the recoil, which is done with a new method based on a recoil library. Our result, 2.028 {+-} 0.072 GeV, is in agreement with the predictions of the standard model and is the most precise direct measurement result from a single experiment to date.
Date:
September 1, 2009
Creator:
Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of B(d) mixing using opposite-side flavor tagging
We report on a measurement of the B{sub d}{sup 0} mixing frequency and the calibration of an opposite-side flavor tagger in the D0 experiment. Various properties associated with the b quark on the opposite side of the reconstructed B meson are combined using a likelihood-ratio method into a single variable with enhanced tagging power. Its performance is tested with data, using a large sample of reconstructed semileptonic B {yields} {mu}D{sup 0} X and B {yields} {mu}D* X decays, corresponding to an integrated luminosity of approximately 1 fb{sup -1}. The events are divided into groups depending on the value of the combined tagging variable, and an independent analysis is performed in each group. Combining the results of these analyses, the overall effective tagging power is found to be {var_epsilon}{prime}D{sup 2} = (2.48 {+-} 0.21{sub -0.06}{sup +0.08})%. The measured B{sub d}{sup 0} mixing frequency {Delta}m{sub d} = 0.506 {+-} 0.020 (stat) {+-} 0.016 (syst) ps{sup -1} is in good agreement with the world average value.
Date:
September 1, 2006
Creator:
Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the CP-violation parameter of B0 mixing and decay with p anti-p ---> mu mu X data
The authors measure the dimuon charge asymmetry A in p{bar p} collisions at a center of mass energy {radical}s 1960 GeV. The data was recorded with the D0 detector and corresponds to an integrated luminosity of approximately 1.0 fb{sup -1}. Assuming that the asymmetry A is due to asymmetric B{sup 0} {leftrightarrow} {bar B}{sup 0} mixing and decay, they extract the CP-violation parameter of B{sup 0} mixing and decay: R({epsilon}{sub B{sup 0}}/1) + |{epsilon}{sub B{sup 0}}|{sup 2} = A{sub B{sup 0}}/4 = -0.0023 {+-} 0.0011(stat) {+-} 0.0008(syst). A{sub B{sup 0}} is the dimuon charge asymmetry from decays of B{sup 0}{bar B}{sup 0} pairs. The general case, with CP violation in both B{sup 0} and B{sub s}{sup 0} systems, is also considered. Finally they obtain the forward-backward asymmetry that quantifies the tendency of {mu}{sup +} to go in the proton direction and {mu}{sup -} to go in the anti-proton direction. The results are consistent with the standard model and constrain new physics.
Date:
September 1, 2006
Creator:
Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the muon charge asymmetry from W boson decays
We present a measurement of the muon charge asymmetry from W boson decays using 0.3 fb{sup -1} of data collected at {radical}s = 1.96 GeV between 2002 and 2004 with the D0 detector at the Fermilab Tevatron p{bar p} Collider. We compare our findings with expectations from next-to-leading-order calculations performed using the CTEQ6.1M and MRST04 NLO parton distribution functions. Our findings can be used to constrain future parton distribution function fits.
Date:
September 1, 2007
Creator:
Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the top quark mass in the dilepton channel
We present a measurement of the top quark mass in the dilepton channel based on approximately 370 pb{sup -1} of data collected by the D0 experiment during Run II of the Fermilab Tevatron collider. We employ two different methods to extract the top quark mass. We show that both methods yield consistent results using ensemble tests of events generated with the D0 Monte Carlo simulation. We combine the results from the two methods to obtain a top quark mass m{sub t} = 178.1 {+-} 8.2 GeV. The statistical uncertainty is 6.7 GeV and the systematic uncertainty is 4.8 GeV.
Date:
September 1, 2006
Creator:
Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the top quark mass in the lepton+jets final state with the matrix element method
We present a measurement of the top quark mass with the Matrix Element method in the lepton+jets final state. As the energy scale for calorimeter jets represents the dominant source of systematic uncertainty, the Matrix Element likelihood is extended by an additional parameter, which is defined as a global multiplicative factor applied to the standard energy scale. The top quark mass is obtained from a fit that yields the combined statistical and systematic jet energy scale uncertainty.
Date:
September 1, 2006
Creator:
Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the W boson helicity in top quark decay at D0
The authors present a measurement of the fraction f{sub +} of right-handed W bosons produced in top quark decays, based on a candidate sample of t{bar t} events in the {ell}+jets and dilepton decay channels corresponding to an integrated luminosity of 370 pb{sup -1} collected by the D0 detector at the Fermilab Tevatron p{bar p} Collider at {radical}s = 1.96 TeV. They reconstruct the decay angle {theta}* for each lepton. By comparing the cos{theta}* distribution from the data with those for the expected background and signal for various values of f{sub +}, they find f{sub +} = 0.056 {+-} 0.080(stat) {+-} 0.057(syst). (f{sub +} < 0.23 at 95% C.L.), consistent with the standard model prediction of f{sub +} = 3.6 x 10{sup -4}.
Date:
September 1, 2006
Creator:
Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M.; Adams, T. et al.
Object Type:
Article
System:
The UNT Digital Library
DZero data-intensive computing on the Open Science Grid
High energy physics experiments periodically reprocess data, in order to take advantage of improved understanding of the detector and the data processing code. Between February and May 2007, the DZero experiment has reprocessed a substantial fraction of its dataset. This consists of half a billion events, corresponding to about 100 TB of data, organized in 300,000 files. The activity utilized resources from sites around the world, including a dozen sites participating to the Open Science Grid consortium (OSG). About 1,500 jobs were run every day across the OSG, consuming and producing hundreds of Gigabytes of data. Access to OSG computing and storage resources was coordinated by the SAM-Grid system. This system organized job access to a complex topology of data queues and job scheduling to clusters, using a SAM-Grid to OSG job forwarding infrastructure. For the first time in the lifetime of the experiment, a data intensive production activity was managed on a general purpose grid, such as OSG. This paper describes the implications of using OSG, where all resources are granted following an opportunistic model, the challenges of operating a data intensive activity over such large computing infrastructure, and the lessons learned throughout the project.
Date:
September 1, 2007
Creator:
Abbott, B.; U., /Oklahoma; Baranovski, A.; Diesburg, M.; Garzoglio, G.; /Fermilab et al.
Object Type:
Article
System:
The UNT Digital Library
Airborne Dust Cloud Measurements at the INL National Security Test Range
On July 11, 2007, a surface, high-explosive test (<20,000 lb TNT-equivalent) was carried out at the National Security Test Range (NSTR) on the Idaho National Laboratory (INL) Site. Aircraft-mounted rapid response (1-sec) particulate monitors were used to measure airborne PM-10 concentrations directly in the dust cloud and to develop a PM-10 emission factor that could be used for subsequent tests at the NSTR. The blast produced a mushroom-like dust cloud that rose approximately 2,500–3,000 ft above ground level, which quickly dissipated (within 5 miles of the source). In general, the cloud was smaller and less persistence than expected, or that might occur in other areas, likely due to the coarse sand and subsurface conditions that characterize the immediate NSTR area. Maximum short time-averaged (1-sec) PM-10 concentrations at the center of the cloud immediately after the event reached 421 µg m-3 but were rapidly reduced (by atmospheric dispersion and fallout) to near background levels (~10 µg m-3) after about 15 minutes. This occurred well within the INL Site boundary, about 8 km (5 miles) from the NSTR source. These findings demonstrate that maximum concentrations in ambient air beyond the INL Site boundary (closest is 11.2 km from NSTR) from these types …
Date:
September 1, 2007
Creator:
Abbott, Michael L.; Stanley, Norm; Radke, Larry & Smeltzer, Charles
Object Type:
Report
System:
The UNT Digital Library