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High pressure calibration with a new absolute pressure gauge

Description: The simultaneous measurement of length and transit time of a specimen under pressure was used to develop a new way of determining absolute high pressure. The mercury freezing point at 0 deg C was deterinined with this new method at 7571.2 plus or minus 1.6 bars. Accurate high-pressure calibration of secondary pressure gages such as manganin gages is possible with this method. The maximum deviation from linearity of the present gage studied is 11.6 plus or minus 1 bars between atmospheric pressure and the mercury freezing point at 0 deg C. (auth)
Date: January 1, 1973
Creator: Ruoff, A.L.; Lincoln, R.C. & Chen, Y.C.
Partner: UNT Libraries Government Documents Department

New absolute high pressure gauge

Description: A new absolute pressure measurement system based on the simultaneous measurement of length and ultrasonic transit times is described. The system was used to determine the transition pressure of pure mercury at 0 deg C at 7571.2 plus or minus 1.6 bars. It is particularly advantageous to use a device for calibrating secondary gauges such as manganin gauges inasmuch as it gives a highly accurate measurement of nonlinearities in such secondary gages. The gage calibrated in the present study reaches a maximum deviation from linearity of 11.6 bars at a pressure midway between atmospheric pressure and the 0 deg C mercury melting pressure. (auth)
Date: January 1, 1972
Creator: Ruoff, A.L.; Lincoln, R.C. & Chen, Y.C.
Partner: UNT Libraries Government Documents Department

Probing {anti u}/{anti d} asymmetry in the proton via quarkonium and W/Z production

Description: The experimented and theoretical status of the flavor dependence of the sea quark distributions in the proton is summarized. Sensitivities of {ital J}/{Psi}, {Gamma}, and {ital W/Z} production to the {ital {anti u}/{anti d}} asymmetry are then discussed.
Date: December 31, 1995
Creator: Peng, J.C.; Jansen, D.M. & Chen, Y.C.
Partner: UNT Libraries Government Documents Department

Research and evaluation of biomass resources/conversion/utilization systems (market/experimental analysis for development of a data base for a fuels from biomass model). Quarterly technical progress report, November 1, 1979-January 31, 1980

Description: The biomass allocation model has been developed and is undergoing testing. Data bases for biomass feedstock and thermochemical products are complete. Simulated data on process efficiency and product costs are being used while more accurate data are being developed. Market analyses data are stored for the biomass allocation model. The modeling activity will assist in providing process efficiency information required for the allocation model. Process models for entrained bed and fixed bed gasifiers based on coal have been adapted to biomass. Fuel product manufacturing costs will be used as inputs for the data banks of the biomass allocations model. Conceptual economics have been generated for seven of the fourteen process configurations via a biomass economic computer program. The PDU studies are designed to demonstrate steady state thermochemical conversions of biomass to fuels in fluidized, moving and entrained bed reactor configurations. Pulse tests in a fluidized bed to determine the effect of particle size on reaction rates and product gas composition have been completed. Two hour shakedown tests using peanut hulls and wood as the biomass feedstock and the fluidized bed reactor mode have been carried out. A comparison was made of the gas composition using air and steam - O/sub 2/. Biomass thermal profiles and biomass composition information shall be provided. To date approximately 70 biomass types have been collected. Chemical characterization of this material has begun. Thermal gravimetric, pyrogaschromatographic and effluent gas analysis has begun on pelletized samples of these biomass species.
Date: January 1, 1980
Creator: Ahn, Y.K.; Chen, Y.C.; Chen, H.T.; Helm, R.W.; Nelson, E.T.; Shields, K.J. et al.
Partner: UNT Libraries Government Documents Department

Phase stability in Ga{sub x}In{sub 1{minus}x}As{sub y}Sb{sub 1{minus}y}/GaSb heterostructures

Description: The crystallographic and microstructural characteristics of liquid phase epitaxy lattice-matched In{sub x}Ga{sub (1{minus}x)}As{sub y}Sb{sub (1{minus}y)}/GaSb (100) heterostructures is presented. Using both transmission electron microscopy and high resolution X-ray diffraction, a variety of diffusional based phase transformations in the epitaxial films are observed, including: spinodal decomposition, compositional modulations of the order of 30 nm, and weak long range ordering. These results are interpreted in terms of the possible influence of substrate surface structure on the phase stability of epitaxial layers.
Date: October 1, 1998
Creator: Chen, Y.C.; Bucklen, V.; Rajan, K.; Freeman, M.; Cardines, R.P. Jr.; Nichols, G. et al.
Partner: UNT Libraries Government Documents Department

Finding the charge of the top quark in the dilepton channel

Description: There is a question about the identity of the top quark. Is it the top quark of the Standard Model (SM) with electric charge 2/3 or is it an exotic quark with charge -4/3? An exotic quark has been proposed by D. Chang et al. [1]. This analysis will use the standard CDF run II dilepton sample. The key ingredients of this analysis are the correct pairing of the lepton and b-jet, the determination of the charge of the b-jet. The analysis proceeds by using a binomial distribution and is formulated so that rejecting one hypothesis means support for the other hypothesis.
Date: August 1, 2006
Creator: Beretvas, A.; Antos, J.; Chen, Y.C.; Gunay, Z.; Sorin, V.; Tollefson, K. et al.
Partner: UNT Libraries Government Documents Department

Study of the Rare Hyperon Decay ${\boldmath \Omega^\mp \to \Xi^\mp \: \pi^+\pi^-}$

Description: The authors report a new measurement of the decay {Omega}{sup -} {yields} {Xi}{sup -} {pi}{sup +}{pi}{sup -} with 76 events and a first observation of the decay {bar {Omega}}{sup +} {yields} {bar {Xi}}{sup +} {pi}{sup +}{pi}{sup -} with 24 events, yielding a combined branching ratio (3.74{sub -0.56}{sup +0.67}) x 10{sup -4}. This represents a factor 25 increase in statistics over the best previous measurement. No evidence is seen for CP violation, with {Beta}({Omega}{sup -} {yields} {Xi}{sup -} {pi}{sup +}{pi}{sup -}) = 4.04{sub -0.71}{sup +0.83} x 10{sup -4} and {Beta}({bar {Omega}}{sup +} {yields} {bar {Xi}}{sup +} {pi}{sup +}{pi}{sup -}) = 3.15{sub -0.89}{sup +1.12} x 10{sup -4}. Contrary to theoretical expectation, they see little evidence for the decays {Omega}{sup -} {yields} {Xi}*{sub 1530}{sup 0} {pi}{sup -} and {bar {Omega}}{sup +} {yields} {bar {Xi}}*{sub 1530}{sup 0} {pi}{sup +} and place a 90% C.L. upper limit on the combined branching ratio {Beta}({Omega}{sup -}({bar {Omega}}{sup +}) {yields} {Xi}*{sub 1530}{sup 0} ({bar {Xi}}*{sub 1530}{sup 0}){pi}{sup {-+}}) < 7.0 x 10{sup -5}.
Date: July 27, 2010
Creator: Kamaev, O.; Solomey, N.; Burnstein, R.A.; Chakravorty, A.; CHen, Y.C.; Choong, W.S. et al.
Partner: UNT Libraries Government Documents Department

Data production models for the CDF experiment

Description: The data production for the CDF experiment is conducted on a large Linux PC farm designed to meet the needs of data collection at a maximum rate of 40 MByte/sec. We present two data production models that exploits advances in computing and communication technology. The first production farm is a centralized system that has achieved a stable data processing rate of approximately 2 TByte per day. The recently upgraded farm is migrated to the SAM (Sequential Access to data via Metadata) data handling system. The software and hardware of the CDF production farms has been successful in providing large computing and data throughput capacity to the experiment.
Date: June 1, 2006
Creator: Antos, J.; Babik, M.; Benjamin, D.; Cabrera, S.; Chan, A.W.; Chen, Y.C. et al.
Partner: UNT Libraries Government Documents Department

Measurement of the asymmetry in the decay Antiomega+ ---> Antilambda K+ ---> anti-p pi+ K+

Description: The asymmetry in the {bar p} angular distribution in the sequential decay {bar {Omega}}{sup +} {yields} {bar {Lambda}}K{sup +} {yields} {bar p}{pi}{sup +}K{sup +} has been measured to be {bar {alpha}}{sub {Omega}}{bar {alpha}}{sub {Lambda}} = [+1.16{+-}0.18(stat){+-}0.17(syst)]x10{sup -2} using 1.89x10{sup 6} unpolarized {bar {Omega}}{sup +} decays recorded by the Hyper CP (E871) experiment at Fermilab. Using the known value of {alpha}{sub {Lambda}}, and assuming that {bar {alpha}}{sub {Lambda}} = -{alpha}{sub {Lambda}}, {bar {alpha}}{sub {Omega}} = [-1.81{+-}0.28(stat){+-}0.26(syst)]x10{sup -2}. A comparison between this measurement of {bar {alpha}}{sub {Omega}}{bar {alpha}}{sub {Lambda}} and recent measurements of {alpha}{sub {Omega}}{alpha}{sub {Lambda}} made by HyperCP shows no evidence of a violation of CP symmetry.
Date: January 1, 2006
Creator: Lu, L.C.; Burnstein, R.A.; Chakravorty, A.; Chen, Y.C.; Choong, W.S.; Clark, K. et al.
Partner: UNT Libraries Government Documents Department

Search for CP violation in hyperon decays.

Description: Direct CP violation in nonleptonic hyperon decays can be established by comparing the decays of hyperons and anti-hyperons. For {Xi} decay to {Lambda} {pi} followed by {Lambda} to p{pi}, the proton distribution in the rest frame of Lambda is governed by the product of the decay parameters {alpha}{sub {Xi}} {alpha}{sub {Lambda}}. The asymmetry A{sub {Xi}{Lambda}}, proportional to the difference of {alpha}{sub {Xi}}{alpha}{sub {Lambda}} of the hyperon and anti-hyperon decays, vanishes if CP is conserved. We report on an analysis of a fraction of 1997 and 1999 data collected by the Hyper CP (E871) collaboration during the fixed-target runs at Fermilab. The preliminary measurement of the asymmetry is {Alpha}{sub {Xi}{Lambda}} = [-7 {+-} 12(stat) {+-} 6.2(sys)] x 10{sup -4}, an order of magnitude better than the present limit.
Date: October 25, 2002
Creator: Zyla, Piotr; Chan, A.; Chen, Y.C.; Ho, C.; Teng, P.K.; Choong, W.S. et al.
Partner: UNT Libraries Government Documents Department

Examining CP symmetry in strange baryon decay

Description: Non-conservation of CP symmetry can manifest itself in non-lepton ichyperon decays as a difference in the decay parameter between the strange-baryon decay and its charge conjugate. By comparing the decay distribution in the {Lambda} helicity frame for the decay sequence {Xi}{sup -} {yields} {Lambda}{pi}{sup -}, {Lambda} {yields} p{pi}{sup -} with that of {bar {Xi}}{sup +} decay, E756 at Fermilab did not observe any CP-odd effect at the 10{sup -2} level. The status of a follow-up experiment, HyperCP (FNAL E871), to search for CP violation in charged {Xi}-{Lambda} decay with a sensitivity of 10{sup -4} is also presented.
Date: April 5, 2000
Creator: Luk, Kam-Biu; Collaboration, Fermilab E756; Collaboration, HyperCP; Burnstein, R.A.; Chakravorty, A.; Chan, A. et al.
Partner: UNT Libraries Government Documents Department

Beauty and charm production from Fermilab experiment 789

Description: Experiment 789 is a fixed-target experiment at Fermilab designed to study low-multiplicity decays of charm and beauty. During the 1991 run. E789 collected {approx} 10{sup 9} events using an 800 GeV proton beam incident upon gold and beryllium targets. Analyses of these data include searches for b {yields} J/{psi}+{Chi} decays and {Alpha}- dependence measurements of neutral D meson production. Preliminary results from the 1991 run are presented in this paper.
Date: June 1, 1993
Creator: Jansen, D.M.; Boissevain, J.; Carey, T.A.; Jeppesen, R.G.; Kapustinsky, J.S.; Lane, D.W. et al.
Partner: UNT Libraries Government Documents Department

Exotic physics: search for new physics leading to high mass tau pairs with ppbar collisions at 1.96 tev using cdf ii

Description: Abstract: We present the results of a search for anomalous resonant production of tau lepton pairs with large invariant mass, the first such search using the CDF II Detector in Run II of the Tevatron p{bar p} collider. Such anomalous production could arise from various new physics processes. In a data sample corresponding to 195 pb{sup -1} of integrated luminosity we predict 2.8 {+-} 0.5 events from Standard Model background processes and observe 4. We use this result to set limits on the production of heavy scalar and vector particles decaying to tau lepton pairs.
Date: June 15, 2005
Creator: Academia Sinica Institute of Physics
Partner: UNT Libraries Government Documents Department