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2,685 Matching Results
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2009 Toxic Chemical Release Inventory Report for the Emergency Planning and Community Right-to-Know Act of 1986, Title III, Section 313
For reporting year 2009, Los Alamos National Laboratory (LANL) submitted a Form R report for lead as required under the Emergency Planning and Community Right-to- Know Act (EPCRA) Section 313. No other EPCRA Section 313 chemicals were used in 2009 above the reportable thresholds. This document was prepared to provide a description of the evaluation of EPCRA Section 313 chemical use and threshold determinations for LANL for calendar year 2009, as well as to provide background information about data included on the Form R reports.
Date:
November 1, 2010
Creator:
(ENV-ES), Environmental Stewardship Group
Object Type:
Report
System:
The UNT Digital Library
Development of Regional Wind Resource and Wind Plant Output Datasets: Final Subcontract Report, 15 October 2007 - 15 March 2009
This report describes the development of the necessary and needed wind and solar datasets used in the Western Wind and Solar Integration Study (WWSIS).
Date:
March 1, 2010
Creator:
3TIER, Seattle, Washington
Object Type:
Report
System:
The UNT Digital Library
Epicyclic Twin-helix Magnetic Structure for Parametric-resonance Ionization Cooling
ParaÂmetÂric-resÂoÂnance IonÂizaÂtion CoolÂing (PIC) is enÂviÂsioned as the final 6D coolÂing stage of a high-luÂmiÂnosÂiÂty muon colÂlidÂer. ImÂpleÂmentÂing PIC imÂposÂes strinÂgent conÂstraints on the coolÂing chanÂnel's magÂnetÂic opÂtics deÂsign. This paper preÂsents a linÂear opÂtics soÂluÂtion comÂpatÂiÂble with PIC. Our soÂluÂtion conÂsists of a suÂperÂpoÂsiÂtion of two opÂpoÂsite-heÂlicÂiÂty equal-peÂriÂod and equal-strength heÂliÂcal dipole harÂmonÂics and a straight norÂmal quadrupole. We demonÂstrate that such a sysÂtem can be adÂjustÂed to meet all of the PIC linÂear opÂtics reÂquireÂments while reÂtainÂing large acÂcepÂtance.
Date:
May 1, 2010
Creator:
A. Afanasev, R.P. Johnson, Y.S. Derbenev, V.S. Morozov
Object Type:
Article
System:
The UNT Digital Library
Energy Recovery Linac: 5 Cell 704 MHz SRF Cavity
N/A
Date:
January 1, 2010
Creator:
A., Burrill
Object Type:
Report
System:
The UNT Digital Library
Energy Recovery Linac: SRF Electron Gun
N/A
Date:
January 1, 2010
Creator:
A., Burrill
Object Type:
Report
System:
The UNT Digital Library
Energy Recovery Linac: Magnetic Measurement of the ERL Magnets
N/A
Date:
January 1, 2010
Creator:
A., Jain
Object Type:
Report
System:
The UNT Digital Library
Progress of Bep Treatments on Nb at JLAB
Recent experimental results have indicated that Buffered Electropolishing (BEP) is a promising candidate for the next generation of surface treatment technique for Nb superconducting radio frequency (SRF) cavities to be used in particle accelerators. In order to lay the foundation for using BEP as the next generation surface treatment technique for Nb SRF cavities, some fundamental aspects of BEP treatments for Nb have to be investigated. In this report, recent progress on BEP study at JLab is shown. Improvements on the existing vertical BEP are made to allow water cooling from outside of a Nb single cell cavity in addition to cooling provided by acid circulation so that the temperature of the cavity can be stable during processing. Some investigation on the electrolyte mixture was performed to check the aging effect of the electrolyte. It is shown that good polishing results can still be obtained on Nb at a current density of 171 mA/cm when the BEP electrolyte was at the stationary condition and was more than 1.5 years old.
Date:
May 1, 2010
Creator:
A.T. Wu, S. Jin, R.A. Rimmer,X.Y. Lu, K. Zhao
Object Type:
Article
System:
The UNT Digital Library
Images of Quark Intrinsic Motion in Covariant Parton Model
We discuss the relations between TMDs and PDFs in the framework of the covariant parton model. The quark OAM and its connection to TMDs are studied as well.
Date:
April 1, 2010
Creator:
A.V. Efremov, P. Schweitzer, O.V. Teryaev, P. Zavada
Object Type:
Article
System:
The UNT Digital Library
Combined Tevatron upper limit on gg -> H -> W^+W^- and constraints on the Higgs boson mass in fourth-generation fermion models
We combine results from searches by the CDF and D0 collaborations for a standard model Higgs boson (H) in the process gg {yields} H {yields} W{sup +}W{sup -} in p{bar p} collisions at the Fermilab Tevatron Collider at {radical}s = 1.o6 TeV. With 4.8 fb{sup -1} of itnegrated luminosity analyzed at CDF and 5.4 fb{sup -1} at D0, the 95% Confidence Level upper limit on {sigma}(gg {yields} H) x {Beta}(H {yields} W{sup +}W{sup -}) is 1.75 pb at m{sub H} = 120 GeV, 0.38 pb at m{sub H} = 165 GeV, and 0.83 pb at m{sub H} = 200 GeV. Assuming the presence of a fourth sequential generation of fermions with large masses, they exclude at the 95% Confidence Level a standard-model-like Higgs boson with a mass between 131 and 204 Gev.
Date:
May 1, 2010
Creator:
Aaltonen, T.; Abazov, V. M.; Abbott, B.; Abolins, M.; Acharya, B. S.; Adams, M. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the ttbar Production Cross Section in ppbar Collisions at sqrt(s)=1.96 TeV using Soft Electron b-Tagging
We present a measurement of the top quark pair production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using a data sample corresponding to 1.7 fb{sup -1} of integrated luminosity collected with the Collider Detector at Fermilab. We reconstruct t{bar t} events in the lepton+jets channel, consisting of e{nu}+jets and {mu}{nu}+jets final states. The dominant background is the production of W bosons in association with multiple jets. To suppress this background, we identify electrons from the semileptonic decay of heavy-flavor jets ('soft electron tags'). From a sample of 2196 candidate events, we obtain 120 tagged events with a background expectation of 51 {+-} 3 events, corresponding to a cross section of {sigma}{sub t{bar t}} = 7.8 {+-} 2.4 (stat) {+-} 1.6 (syst) {+-} 0.5 (lumi) pb. We assume a top-quark mass of 175 GeV/c{sup 2}. This is the first measurement of the t{bar t} cross section with soft electron tags in Run II of the Tevatron.
Date:
February 1, 2010
Creator:
Aaltonen, T.; Adelman, J.; Akimoto, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D. et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of Z gamma Production in pbar{p} Collisions at sqrt{s} = 1.96 TeV
The production rate and kinematics of photons produced in association with Z bosons are studied using 2 fb{sup -1} of p{bar p} collision data collected at the Collider Detector at Fermilab. The cross section for p{bar p} {yields} {ell}{sup +}{ell}{sup -}{gamma} + X (where the leptons {ell} are either muons or electrons with dilepton mass M{sub {ell}{ell}} > 40 GeV/c{sup 2}, and where the photon has transverse energy E{sub T}{sup {gamma}} > 7 GeV and is well separated from the leptons) is 4.6 {+-} 0.2 (stat) {+-} 0.3 (syst) {+-} 0.3 (lum) pb, which is consistent with standard model expectations. We use the photon ET distribution from Z{gamma} events where the Z has decayed to {mu}{sup +}{mu}{sup -}, e{sup +}e{sup -}, or {nu}{bar {nu}} to set limits on anomalous (non-standard-model) trilinear couplings between photons and Z bosons.
Date:
April 1, 2010
Creator:
Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type:
Article
System:
The UNT Digital Library
Observation of Single Top Quark Production and Measurement of |Vtb| with CDF
We report the observation of electroweak single top quark production in 3.2 fb{sup -1} of p{bar p} collision data collected by the Collider Detector at Fermilab at {radical}s = 1.96 TeV. Candidate events in the W+jets topology with a leptonically decaying W boson are classified as signal-like by four parallel analyses based on likelihood functions, matrix elements, neural networks, and boosted decision trees. These results are combined using a super discriminant analysis based on genetically evolved neural networks in order to improve the sensitivity. This combined result is further combined with that of a search for a single top quark signal in an orthogonal sample of events with missing transverse energy plus jets and no charged lepton. We observe a signal consistent with the standard model prediction but inconsistent with the background-only model by 5.0 standard deviations, with a median expected sensitivity in excess of 5.9 standard deviations. We measure a production cross section of 2.3{sub -0.5}{sup +0.6}(stat + sys) pb, extract the CKM matrix element value |V{sub tb}| = 0.91{sub -0.11}{sup +0.11}(stat + sys) {+-} 0.07(theory), and set a lower limit |V{sub tb}| > 0.71 at the 95% confidence level, assuming m{sub t} = 175 GeV/c{sup 2}.
Date:
April 1, 2010
Creator:
Aaltonen, T.; Adelman, J.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type:
Article
System:
The UNT Digital Library
Studying the Underlying Event in Drell-Yan and High Transverse Momentum Jet Production at the Tevatron
We study the underlying event in proton-antiproton collisions by examining the behavior of charged particles (transverse momentum p{sub T} > 0.5 GeV/c, pseudorapidity |{eta}| < 1) produced in association with large transverse momentum jets ({approx}2.2 fb{sup -1}) or with Drell-Yan lepton-pairs ({approx}2.7 fb{sup -1}) in the Z-boson mass region (70 < M(pair) < 110 GeV/c{sup 2}) as measured by CDF at 1.96 TeV center-of-mass energy. We use the direction of the lepton-pair (in Drell-Yan production) or the leading jet (in high-p{sub T} jet production) in each event to define three regions of {eta}-{phi} space; toward, away, and transverse, where {phi} is the azimuthal scattering angle. For Drell-Yan production (excluding the leptons) both the toward and transverse regions are very sensitive to the underlying event. In high-p{sub T} jet production the transverse region is very sensitive to the underlying event and is separated into a MAX and MIN transverse region, which helps separate the hard component (initial and final-state radiation) from the beam-beam remnant and multiple parton interaction components of the scattering. The data are corrected to the particle level to remove detector effects and are then compared with several QCD Monte-Carlo models. The goal of this analysis is to provide …
Date:
March 1, 2010
Creator:
Aaltonen, T.; Adelman, J.; Gonzalez, B.Alvarez; Amerio, S.; Amidei, D.; Anastassov, A. et al.
Object Type:
Article
System:
The UNT Digital Library
Improved Search for a Higgs Boson Produced in Association with Z->l+l- in proton antiproton Collisions at sqrt(s) = 1.96 TeV
We present a search for the standard model Higgs boson produced with a Z boson in 4.1 fb{sup -1} of data collected with the CDF II detector at the Tevatron. In events consistent with the decay of the Higgs boson to a bottom-quark pair and the Z boson to electrons or muons, we set 95% credibility level upper limits on the ZH production cross section times the H {yields} b{bar b} branching ratio. Improved analysis methods enhance signal sensitivity by 20% relative to previous searches beyond the gain due to the larger data sample. At a Higgs boson mass of 115 GeV/c{sup 2} we set a limit of 5.9 times the standard model value.
Date:
September 1, 2010
Creator:
Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Object Type:
Article
System:
The UNT Digital Library
Search for the supersymmetric partner of the top quark in ppbar collisions at sqrt(s) = 1.96 TeV
We present a search for the lightest supersymmetric partner of the top quark in proton-antiproton collisions at a center-of-mass energy {radical}s = 1.96 TeV. This search was conducted within the framework of the R-parity conserving minimal supersymmetric extension of the standard model, assuming the stop decays dominantly to a lepton, a sneutrino, and a bottom quark. We searched for events with two oppositely-charged leptons, at least one jet, and missing transverse energy in a data sample corresponding to an integrated luminosity of 1 fb{sup -1} collected by the CDF experiment. No significant evidence of a stop quark signal was found. Exclusion limits at 95% confidence level in the stop quark versus sneutrino mass plane are set. Stop quark masses up to 180 GeV/c{sup 2} are excluded for sneutrino masses around 45 GeV/c{sup 2}, and sneutrino masses up to 116 GeV/c{sup 2} are excluded for stop quark masses around 150 GeV/c{sup 2}.
Date:
September 1, 2010
Creator:
Aaltonen, T.; Alvarez Gonzalez, B.; Amerio, S.; Amidei, D.; Anastassov, A.; Annovi, A. et al.
Object Type:
Article
System:
The UNT Digital Library
First Measurement of the Ratio sigma_(t-tbar) / sigma_(Z/\gamma*->ll) and Precise Extraction of the t-tbar Cross Section
We report a measurement of the ratio of the t{bar t} to Z/{gamma}* production cross sections in {radical}s = 1.96 TeV p{bar p} collisions using data corresponding to an integrated luminosity of up to 4.6 fb{sup -1}, collected by the CDF II detector. The t{bar t} cross section ratio is measured using two complementary methods, a b-jet tagging measurement and a topological approach. By multiplying the ratios by the well-known theoretical Z/{gamma}* {yields} ll cross section predicted by the standard model, the extracted t{bar t} cross sections are effectively insensitive to the uncertainty on luminosity. A best linear unbiased estimate is used to combine both measurements with the result {sigma}{sub t{bar t}} = 7.70 {+-} 0.52 pb, for a top-quark mass of 172.5 GeV/c{sup 2}.
Date:
April 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the $B^-$ lifetime using a simulation free approach for trigger bias correction
The collection of a large number of B hadron decays to hadronic final states at the CDF II detector is possible due to the presence of a trigger that selects events based on track impact parameters. However, the nature of the selection requirements of the trigger introduces a large bias in the observed proper decay time distribution. A lifetime measurement must correct for this bias and the conventional approach has been to use a Monte Carlo simulation. The leading sources of systematic uncertainty in the conventional approach are due to differences between the data and the Monte Carlo simulation. In this paper they present an analytic method for bias correction without using simulation, thereby removing any uncertainty between data and simulation. This method is presented in the form of a measurement of the lifetime of the B{sup -} using the mode B{sup -} {yields} D{sup 0}{pi}{sup -}. The B{sup -} lifetime is measured as {tau}{sub B{sup -}} = 1.663 {+-} 0.023 {+-} 0.015 ps, where the first uncertainty is statistical and the second systematic. This new method results in a smaller systematic uncertainty in comparison to methods that use simulation to correct for the trigger bias.
Date:
April 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the Top Quark Mass and ppbar -> ttbar Cross Section in the All-Hadronic Mode with the CDFII Detector
We present a measurement of the top quark mass and of the top-antitop pair production cross section using p{bar p} data collected with the CDF II detector at the Tevatron Collider at the Fermi National Accelerator Laboratory and corresponding to an integrated luminosity of 2.9 fb{sup -1}. We select events with six or more jets satisfying a number of kinematical requirements imposed by means of a neural network algorithm. At least one of these jets must originate from a b quark, as identified by the reconstruction of a secondary vertex inside the jet. The mass measurement is based on a likelihood fit incorporating reconstructed mass distributions representative of signal and background, where the absolute jet energy scale (JES) is measured simultaneously with the top quark mass. The measurement yields a value of 174.8 {+-} 2.4(stat+JES){sub -1.0}{sup +1.2}(syst)GeV/c{sup 2}, where the uncertainty from the absolute jet energy scale is evaluated together with the statistical uncertainty. The procedure measures also the amount of signal from which we derive a cross section, {sigma}{sub t{bar t}} = 7.2 {+-} 0.5(stat) {+-} 1.0(syst) {+-} 0.4(lum) pb, for the measured values of top quark mass and JES.
Date:
February 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Object Type:
Article
System:
The UNT Digital Library
Search for Randall-Sundrum Gravitons in the Diphoton Channel at CDF
We report on a search for new particles in the diphoton channel using a data sample of p{bar p} collisions at {radical}s = 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, with an integrated luminosity of 5.4 fb{sup -1}. The diphoton invariant mass spectrum of the data agrees well with the standard model expectation. We set upper limits on the production cross section times branching ratio for the Randall-Sundrum graviton, as a function of diphoton mass. We subsequently derive lower limits on the graviton mass of 482 GeV/c{sup 2} and 975 GeV/c{sup 2}, at the 95% confidence level, for coupling parameters (k/{bar M}{sub Pl}) of 0.01 and 0.1 respectively.
Date:
December 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Object Type:
Article
System:
The UNT Digital Library
Search for the Production of Scalar Bottom Quarks in $p \bar {p} $ collisions at $\sqrt{s} $ = 1.96 TeV
We report on a search for direct scalar bottom quark (sbottom) pair production in p{bar p} collisions at {radical}s = 1.96 TeV, in events with large missing transverse energy and two jets of hadrons in the final state, where at least one of the jets is required to be identified as originating from a b quark. The study uses a CDF Run II data sample corresponding to 2.65 fb{sup -1} of integrated luminosity. The data are in agreement with the standard model. In an R-parity conserving minimal supersymmetric scenario, and assuming that the sbottom decays exclusively into a bottom quark and a neutralino, 95% confidence-level upper limits on the sbottom pair production cross section of 0.1 pb are obtained. For neutralino masses below 70 GeV/c{sup 2}, sbottom masses up to 230 GeV/c{sup 2} are excluded at 95% confidence level.
Date:
May 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of et al.
Object Type:
Article
System:
The UNT Digital Library
Exclusion of an Exotic Top Quark with -4/3 Electric Charge Using Soft Lepton Tagging
We present a measurement of the electric charge of the top quark using p{bar p} collisions corresponding to an integrated luminosity of 2.7 fb{sup -1} at the CDF II detector. We reconstruct t{bar t} events in the lepton+jets final state and use kinematic information to determine which b-jet is associated with the leptonically- or hadronically-decaying t-quark. Soft lepton taggers are used to determine the b-jet flavor. Along with the charge of the W boson decay lepton, this information permits the reconstruction of the top quark's electric charge. Out of 45 reconstructed events with 2.4 {+-} 0.8 expected background events, 29 are reconstructed as tt with the standard model +2/3 charge, whereas 16 are reconstructed as t{bar t} with an exotic -4/3 charge. This is consistent with the standard model and excludes the exotic scenario at 95% confidence level. This is the strongest exclusion of the exotic charge scenario and the first to use soft leptons for this purpose.
Date:
June 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Adelman, J.; /Chicago U., EFI; Alvarez Gonzalez, B.; Phys., /Oviedo U. /Cantabria Inst. of et al.
Object Type:
Article
System:
The UNT Digital Library
Diffractive W and Z Production at the Fermilab Tevatron
We report on a measurement of the fraction of events with a W or Z boson produced diffractively in {bar p}p collisions at {radical}s = 1.96 TeV, using data from 0.6 fb{sup -1} of integrated luminosity collected with the CDF II detector equipped with a Roman-pot spectrometer that detects the {bar p} from {bar p} + p {yields} {bar p}+[X+W/Z]. We find that (0.97 {+-} 0.11)% of Ws and (0.85 {+-} 0.22)% of Zs are produced diffractively in a region of (anti)proton fractional momentum loss {zeta} of 0.03 < {zeta} < 0.10 and 4-momentum transferred squared t of -1 < t < 0 (GeV/c){sup 2}. We also report on searches for W and Z production in double Pomeron exchange, p+{bar p} {yields} p+[X+W/z]+{bar p}, and on exclusive Z production, {bar p}p {yields} {bar p}+Z+p. No signal is seen above background for these processes, and comparisons are made with expectations.
Date:
July 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type:
Article
System:
The UNT Digital Library
Measurement of the $t\bar{t}$ Production Cross Section with an in situ Calibration of $b$-jet Identification Efficiency
A measurement of the top-quark pair-production cross section in p{bar p} collisions at {radical}s = 1.96 TeV using data corresponding to an integrated luminosity of 1.12 fb{sup -1} collected with the Collider Detector at Fermilab is presented. Decays of top-quark pairs into the final states e{nu} + jets and {mu}{nu} + jets are selected, and the cross section and the b-jet identification efficiency are determined using a new measurement technique which requires that the measured cross sections with exactly one and multiple identified b-quarks from the top-quark decays agree. Assuming a top-quark mass of 175 GeV/c{sup 2}, a cross section of 8.5 {+-} 0.6(stat.) {+-} 0.7(syst.) pb is measured.
Date:
July 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type:
Article
System:
The UNT Digital Library
Top Quark Mass Measurement in the Lepton + Jets Channel Using a Matrix Element Method and \textit{in situ} Jet Energy Calibration
A precision measurement of the top quark mass m{sub t} is obtained using a sample of t{bar t} events from p{bar p} collisions at the Fermilab Tevatron with the CDF II detector. Selected events require an electron or muon, large missing transverse energy, and exactly four high-energy jets, at least one of which is tagged as coming from a b quark. A likelihood is calculated using a matrix element method with quasi-Monte Carlo integration taking into account finite detector resolution and jet mass effects. The event likelihood is a function of m{sub t} and a parameter {Delta}{sub JES} used to calibrate the jet energy scale in situ. Using a total of 1087 events, a value of m{sub t} = 173.0 {+-} 1.2 GeV/c{sup 2} is measured.
Date:
October 1, 2010
Creator:
Aaltonen, T.; Phys., /Helsinki Inst. of; Alvarez Gonzalez, B.; Phys., /Cantabria Inst. of; Amerio, S.; /INFN, Padua et al.
Object Type:
Article
System:
The UNT Digital Library