A study of tau decays of the W boson at CDF (Collider Detector at Fermilab) (open access)

A study of tau decays of the W boson at CDF (Collider Detector at Fermilab)

A report is given of a search for tau decays of the W boson in p{bar p} collisions at {radical}s = 1.8 TeV using the Collider Detector at Fermilab (CDF). A description of a hardware trigger specifically designed to enhance the number of events with tau decays is presented along with the results of a preliminary analysis of data taken during the 1988--89 run of CDF. 10 refs., 4 figs.
Date: January 3, 1990
Creator: Gladney, L. D.
System: The UNT Digital Library
Prospects for top at CDF (open access)

Prospects for top at CDF

During the next two years, the Fermilab Tavatron is expected to deliver approximately 100pb{sup {minus}1} of integrated luminosity. We describe improvements to the CDF detector since the 1988--89 collider run and discuss the prospects for the discovery of the top quark during the 1992--93 collider runs.
Date: June 3, 1992
Creator: Gerdes, D. (Chicago Univ., IL (United States))
System: The UNT Digital Library
Two-component flow study in large-diameter horizontal pipe (open access)

Two-component flow study in large-diameter horizontal pipe

Westinghouse Savannah River Company, Idaho National Engineering Laboratory, and Wyle Laboratory cooperated in a series of single- and two-component calibration tests conducted to obtain sufficient information for calibrating flowmeters, to observe flow patterns, and to estimate void functions. Testing, conducted in large-diameter horizontal pipe, covered total flows of 0.19 to 1.89 m{sup 3}/s (3000 to 30000 gpm) and inlet void fractions up to 40%. A flow regime map, constructed using video images of the flow patterns and void fraction data, was compared with maps from the literature, with generally good agreement for interpretation of flow patterns. 5 refs.
Date: December 3, 1991
Creator: Eghbali, D. A.
System: The UNT Digital Library
Neutron scattering analysis with microscopic optical model potentials (open access)

Neutron scattering analysis with microscopic optical model potentials

A review of microscopic optical model potentials used in the analysis of neutron scattering and analyzing power data below 100 MeV (5 {le}E{sub n}{le}100 MeV) is presented. The quality of the fits to the data over a wide massd ({sup 6}Li-{sup 239}Pu) and energy range is discussed. It is shown that reasonably good agreement with the data is obtained with only three parameters, {lambda}{sub V}, {lambda}{sub W}, and {lambda}{sub SO}, which show a smooth mass and energy dependence. These parameters are normalizing constants to the real (V), and imaginary (W) central potentials and the real spin-orbit (V{sub SO}) potential. 14 refs., 7 figs.
Date: September 3, 1991
Creator: Hansen, L. F.
System: The UNT Digital Library
Recent developments in the Virasoro master equation (open access)

Recent developments in the Virasoro master equation

The Virasoro master equation collects all possible Virasoro constructions which are quadratic in the currents of affine Lie g. The solution space of this system is immense, with generically irrational central charge, and solutions which have so far been observed are generically unitary. Other developments reviewed include the exact C-function, the superconformal master equation and partial classification of solutions by graph theory and generalized graph theories. 37 refs., 1 fig., 1 tab.
Date: September 3, 1991
Creator: Halpern, M.B.
System: The UNT Digital Library
CDF: Recent results and future prospects (open access)

CDF: Recent results and future prospects

We present recent results from the Collider Detector at Fermilab. Searches for the top quark have established a lower bound of M{sub top} > 91 GeV/c{sup 2} (at 95% confidence level). A measurement of B{sup o}{bar B}{sup o} mixing has been obtained from b{bar b} {yields} e{mu}, ee events. Measurements of b-quark production have been obtained from e + X events and J/{psi} + K events. The mass of the W boson has been determined to be M{sub W} = 79.91 {plus minus} 0.39 GeV/c{sup 2}. In searching for new gauge bosons, we have obtained the bounds M{sub Z{prime}} > 412 GeV/c{sup 2} and M{sub W{prime}} > 520 GeV/c{sup 2} (at 95% C.L.). The lower limits on the quark and lepton compositeness scales are 1.4 TeV. In the next two years of data collection, we expect significantly more events for numerous types of physics, due to 25 times more beam luminosity, and improvement to the detector. In the longer term, the Main Injector'' upgrade to the accelerator, further improvements to the detector are being planned to exploit the potentials for physics. We discuss prospects for the discovery of the top quark, precise measurement of properties of b quark, and searches …
Date: March 3, 1992
Creator: Yeh, G.P.
System: The UNT Digital Library
Field Errors in Hybrid Insertion Devices (open access)

Field Errors in Hybrid Insertion Devices

Hybrid magnet theory as applied to the error analyses usedin the design of Advanced Light Source (ALS) insertion devices isreviewed. Sources of field errors in hybrid insertion devices arediscussed.
Date: February 3, 1995
Creator: Schlueter, R.D.
System: The UNT Digital Library
Photoelectron Diffraction of Magnetic Ultrathin Films: Fe/Cu(001) (open access)

Photoelectron Diffraction of Magnetic Ultrathin Films: Fe/Cu(001)

The preliminary results of an ongoing investigation of Fe/Cu(001) are presented here. Energy dependent photoelectron diffraction, including the spin-dependent variant using the multiplet split Fe3s state, is being used to investigate the nanoscale structures formed by near-monolayer deposits of Fe onto Cu(001). Core-level photoemission from the Fe3p and Fe3s states has been generated using synchrotron radiation as the tunable excitation source. Tentatively, a comparison of the experimental Fe3p cross section measurements with multiple scattering calculations indicates that the Fe is in a fourfold hollow site with a spacing of 3.6{Angstrom} between it and the atom directly beneath it, in the third layer. This is consistent with an FCC structure. The possibility of utilizing spin-dependent photoelectron diffraction to investigate magnetic ultrathin films will be demonstrated, using our preliminary spectra of the multiplet-split Fe3s os near-monolayer Fe/Cu(001). 18 refs., 10 figs.
Date: January 3, 1991
Creator: Tobin, J.G. (Lawrence Livermore National Lab., CA (USA)); Wagner, M.K. (Wisconsin Univ., Madison, WI (USA). Dept. of Chemistry); Guo, X.Q. & Tong, S.Y. (Wisconsin Univ., Milwaukee, WI (USA). Dept. of Physics)
System: The UNT Digital Library
Hadron collider physics (open access)

Hadron collider physics

An introduction to the techniques of analysis of hadron collider events is presented in the context of the quark-parton model. Production and decay of W and Z intermediate vector bosons are used as examples. The structure of the Electroweak theory is outlined. Three simple FORTRAN programs are introduced, to illustrate Monte Carlo calculation techniques. 25 refs.
Date: October 3, 1991
Creator: Pondrom, L.
System: The UNT Digital Library
The physics of proton antiproton collisions (open access)

The physics of proton antiproton collisions

This paper contains information information on: accelerator and detector; QCD studies; studies of the electroweak force; The search for the top quark; {beta} physics at hadron colliders; and the search for exotic objects and prospects for the future.
Date: December 3, 1991
Creator: Shochet, M. (Chicago Univ., IL (United States))
System: The UNT Digital Library
Impact of the nuclear equation of state on models of rotating neutron stars (open access)

Impact of the nuclear equation of state on models of rotating neutron stars

The impact of the nuclear equation of state on the properties of rotating neutron stars from two different sources, stable rotation at the general relativistic Kepler period and rotation at the gravitational radiation-reaction driven instability mode, is analyzed. For this purpose models of rotating neutron stars are constructed in the framework of Einstein's theory of general relativity by applying a refined version of Hartle's perturbative stellar structure equations. The investigation is based on a representative collection of a total of seventeen nuclear equations of state, covering both non-relativistic as well as relativistic ones. 41 refs., 3 figs., 2 tabs.
Date: June 3, 1991
Creator: Weber, F. & Glendenning, N.K.
System: The UNT Digital Library
Uv Thomson scattering from x-ray laser plasmas (open access)

Uv Thomson scattering from x-ray laser plasmas

Plasmas produced by irradiating massive carbon targets with a 1.064 {mu}m, 1.5 ns laser pulse at incident energies of {approximately}100 J have been investigated. UV thermal Thomson scattering was used to obtain the electron and ion temperatures, as well as drift velocities. The electron density was obtained by optical interferometry. The results are compared to hydrodynamic computer modeling. 6 refs., 6 figs.
Date: January 3, 1991
Creator: La Fontaine, B.; Baldis, H. A.; Villeneuve, D. M.; Bernard, J. E.; Enright, G. D. (National Research Council of Canada, Ottawa, ON (Canada)); Rosen, M. D. et al.
System: The UNT Digital Library
Studies of the mirrortron ion accelerator concept and its application to heavy-ion drivers (open access)

Studies of the mirrortron ion accelerator concept and its application to heavy-ion drivers

The Mirrortron accelerator is a plasma-based ion accelerator concept that, when implemented, should permit both higher acceleration gradients and higher peak-current capabilities than is possible with conventional induction-type accelerators. Control over the acceleration and focussing of an accelerated beam should approach that achieved in vacuum-field-based ion accelerators. In the Mirrortron a low density (10{sup 10} to 10{sup 11} cm{sup {minus}3}) hot electron'' plasma is confined by a long solenoidal magnetic field capped by mirrors''. Acceleration of prebunched ions is accomplished by activating a series of fast-pulsed mirror coils spaced along the acceleration tube. The hot electrons, being repelled by mirror action, leave the plasma ions behind to create a localized region of high electrical gradient (up to of order 100 MV/m). At the Laboratory an experiment and analyses to elucidate the concept and its scaling laws as applied to heavy-ion drivers are underway and will be described. 4 refs., 5 figs.
Date: April 3, 1991
Creator: Post, R.F.; Schwager, L.A.; Dougless, S.R.; Jones, B.R.; Lambert, M.A. & Larson, D.L.
System: The UNT Digital Library
A Fast Online Event Display for a High Intensity Fixed-Target Spectrometer (open access)

A Fast Online Event Display for a High Intensity Fixed-Target Spectrometer

A workstation-based event display program for the Fermilab Tagged Photon Spectrometer (TPS) is described. Fast displays are required to monitor detector elements, observe hit patterns and energy deposition, and to check track reconstruction. Design considerations, novel features, and performance are designed. 5 refs., 4 figs., 1 tab.
Date: May 3, 1990
Creator: Napier, Austin
System: The UNT Digital Library
Experimental evaluation of vertically versus horizontally split yokes for SSC (Superconducting Super Collider) dipole magnets (open access)

Experimental evaluation of vertically versus horizontally split yokes for SSC (Superconducting Super Collider) dipole magnets

The yoke in SSC dipole magnets provides mechanical support to the collared coil as well as serving as a magnetic element. The yoke and skin are used to increase the coil prestress and reduce collar deflections under excitation. Yokes split on the vertical or horizontal mid-plane offer different advantages in meeting these objectives. To evaluate the relative merits of the two configuration a 1.8 m model dipole was assembled and tested first with horizontally split and then with vertically split yoke laminations. The magnet was extensively instrumented to measure azimuthal and axial stresses in the coil and the cold mass skin resulting from cooldown and excitation. Mechanical behavior of this magnet with each configuration is compared with that of other long and short models and with calculations. 13 refs., 5 figs.
Date: May 3, 1990
Creator: Strait, J.; Coulter, K.; Jaffery, T.; Kerby, J.; Koska, W. & Lamm, M.J.
System: The UNT Digital Library
The reaction of hydroperoxy-propyl radicals with molecular oxygen (open access)

The reaction of hydroperoxy-propyl radicals with molecular oxygen

Addition of hydroperoxy-alkyl radicals to molecular oxygen leads to chain branching in autoignition and engine knock, and in low temperature oxidation of paraffins. Rate constants and product channels for reaction of hydroperoxy-propyl radicals with O{sub 2} are estimated using thermodynamic properties, bimolecular quantum Kassel analysis and transition state theory. Thermochemistry of relevant molecules and radicals is estimated using group additivity and bond dissociation groups for radicals. Results show that rates of the hydroperoxy-propyl radical addition to O{sub 2} are near their high pressure limits at {ge} 1 atm. Main products at 1--15 atm are stabilization, reverse reaction to hydroperoxy-propyl + O{sub 2} and alkyl carbonyl + OH. Reactions of the stabilized adducts, dissociation rates and product channels are estimated using unimolecular quantum Kassel analysis, because stabilization is the most important hydroperoxy-propyl radical + O{sub 2} product channel. Below 700 K, the stabilized peroxy adducts react primarily to hydroperoxy-carbonyl + OH, products which lead to chain branching. Above 700K, the stabilized peroxy adducts react primarily to hydroperoxy-propyl radical + O{sub 2}, initial reactants, which inhibits the overall oxidation. This switchover in channels correlates well observed negative temperature coefficient behavior for propane oxidation. Rate expressions for reaction of each of the three …
Date: December 3, 1993
Creator: Bozzelli, J. W. & Pitz, W. J.
System: The UNT Digital Library
Search for the top quark in the electron-electron and electron-muon channels at D0 (open access)

Search for the top quark in the electron-electron and electron-muon channels at D0

We discuss preliminary results of a search for top quarks using their decays in two di-lepton, with the D0 detector at Fermilab. The present analysis has been optimized to search for a top with mass near 100{sub c{sup 2}}/{sup GeV}, consistent with published limits. In the event sample corresponding to an integrated luminosity of 15pb{sup {minus}1} we observe two events passing all selection cuts. The number of events observed is consistent with the expected number of background events. Consequently, we do not claim the observation of a top decay in the present event sample. We note however, that the kinematic properties of one of the events appear to be far removed from known backgrounds. We discuss the event and show results of the mass likelihood analysis when applied to this event.
Date: December 3, 1993
Creator: Fatyga, M. & Collaboration, The D0
System: The UNT Digital Library
A new comprehensive reaction mechanism for combustion of hydrocarbon fuels (open access)

A new comprehensive reaction mechanism for combustion of hydrocarbon fuels

A chemical kinetic model has been developed which describes pyrolysis, ignition and oxidation of many small hydrocarbon fuels over a wide range of experimental conditions. Fuels include carbon monoxide and hydrogen, methane and other alkane species up to n-butane, ethylene, propene, acetylene, and oxygenated species such as methanol, acetaldehyde and ethanol. Formation of some larger intermediate and product species including benzene, butadiene, large olefins, and cyclopentadiene has been treated in a semi-empirical manner. The reaction mechanism has been tested for conditions that do not involve transport and diffusional processes, including plug flow and stirred reactors, batch reactors and shock tubes. The present kinetic model and its validation differ from previous reaction mechanisms in two ways. First, in addition to conventional combustion data, experiments more commonly associated with chemical engineering problems such as oxidative coupling, oxidative pyrolysis and steam cracking are used to test the reaction mechanism, making it even more general than previous models. In addition, H atom abstraction and some other reaction rates, even for the smaller C{sub 2}, C{sub 3} and C{sub 4} species, are treated using approximations that facilitate future extensions to larger fuels in a convenient manner. Construction of the reaction mechanism and comparisons with experimental …
Date: December 3, 1993
Creator: Ranzi, E.; Sogaro, A.; Gaffuri, P.; Pennati, G.; Westbrook, C. K. & Pitz, W. J.
System: The UNT Digital Library
Isotopic ratio method for determining uranium contamination (open access)

Isotopic ratio method for determining uranium contamination

The presence of high concentrations of uranium in the subsurface can be attributed either to contamination from uranium processing activities or to naturally occurring uranium. A mathematical method has been employed to evaluate the isotope ratios from subsurface soils at the Rocky Flats Nuclear Weapons Plant (RFP) and demonstrates conclusively that the soil contains uranium from a natural source and has not been contaminated with enriched uranium resulting from RFP releases. This paper describes the method used in this determination which has widespread application in site characterizations and can be adapted to other radioisotopes used in manufacturing industries. The determination of radioisotope source can lead to a reduction of the remediation effort.
Date: February 3, 1994
Creator: Miles, R. E. & Sieben, A. K.
System: The UNT Digital Library
Prospects for top at CDF (open access)

Prospects for top at CDF

During the next two years, the Fermilab Tavatron is expected to deliver approximately 100pb{sup {minus}1} of integrated luminosity. We describe improvements to the CDF detector since the 1988--89 collider run and discuss the prospects for the discovery of the top quark during the 1992--93 collider runs.
Date: June 3, 1992
Creator: Gerdes, D.
System: The UNT Digital Library
A comparison between direct spark ignition and prechamber ignition in an internal combustion engine (open access)

A comparison between direct spark ignition and prechamber ignition in an internal combustion engine

We simulated the flow field and flame propagation near top dead center in a generic large-bore internal combustion engine using the COYOTE computer program, which is based on the full Navier-Stokes equations for a fluid mixture. The combustion chamber is a right circular cylinder, and the main charge is uniformly premixed. The calculations are axisymmetric. The results illustrate the differences in flow patterns, flame propagation, and thermal NO production between ignition with a spark plug and with a small prechamber. In the spark-ignited case, the flame propagates away from the spark plug approximately as a segment of a spherical surface, just as expected. With the prechamber, a high speed jet of hot combustion products shoots into the main chamber, quickly producing a large flame sheet that spreads along the piston face. The prechamber run consumes all of the fuel in half the time required by the spark-ignited case. The two cases produce comparable amounts of thermal NO at the end of fuel combustion.
Date: December 3, 1993
Creator: Cloutman, L. D.
System: The UNT Digital Library
Two-component flow study in large-diameter horizontal pipe (open access)

Two-component flow study in large-diameter horizontal pipe

Westinghouse Savannah River Company, Idaho National Engineering Laboratory, and Wyle Laboratory cooperated in a series of single- and two-component calibration tests conducted to obtain sufficient information for calibrating flowmeters, to observe flow patterns, and to estimate void functions. Testing, conducted in large-diameter horizontal pipe, covered total flows of 0.19 to 1.89 m{sup 3}/s (3000 to 30000 gpm) and inlet void fractions up to 40%. A flow regime map, constructed using video images of the flow patterns and void fraction data, was compared with maps from the literature, with generally good agreement for interpretation of flow patterns. 5 refs.
Date: December 3, 1991
Creator: Eghbali, D. A.
System: The UNT Digital Library
Conceptual design of an RTG Facility Transportation System (open access)

Conceptual design of an RTG Facility Transportation System

The conceptual design of an Radioisotope Thermoelectric Generator (RTG) Facility Transportation System which is part of the overall RTG Transportation System has been completed and is described in detail. The Facility Transportation System serves to provide locomotion, cooling, shock protection and data acquisition for the RTG package during loading and unloading sequences. The RTG Facility Transportation System consists of a Transporter Subsystem, a Package Cooling Subsystem, and a Shock Limiting Transit Device Subsystem. The Transporter Subsystem is a uniquely designed welded steel cart combined with a pneumatically-driven hand tug for locomotion. The Package Cooling Subsystem provides five kilowatts of active liquid cooling via an on-board refrigeration system. The Shock limiting Transit Device Subsystem consists of a consumable honeycomb transit frame which provides shock protection for the 3855 kg (8500 LB) RTG package. These subsystems have been combined into an integrated system which will facilitate the unloading and loading of the RTG , of the Transport Trailer as well as meet ALARA radiation Package into and out exposure guidelines.
Date: June 3, 1994
Creator: Black, S. J.; Gentzlinger, R. C. & Lujan, R. E.
System: The UNT Digital Library
Search for the top quark from (e,{mu}) and (e,e) events in the D0 detector in p{bar p} collisions at {radical}s = 1.8 TeV (open access)

Search for the top quark from (e,{mu}) and (e,e) events in the D0 detector in p{bar p} collisions at {radical}s = 1.8 TeV

We present results from searches for top quark production in p{bar p} collisions at the Tevatron collider based on an integrated luminosity of 7.5 pb{sup {minus}1} obtained during the 1992--1993 ran. The present results are confined to decay modes where both the top and anti-top quarks in the event decay semi-leptonically to the ee and e{mu} channels. A lower limit of 103 (99) GeV/c{sup 2} is obtained at 95% confidence level for the top quark mass from the absence of events consistent with standard model top quark decays with background subtraction (no background subtraction). We do however observe one event in the e{mu} channel which cannot be explained by the known backgrounds. While we make no claim that this event is due to top quark decay, it is not inconsistent with a top quark mass in the range 130--170 GeV/c{sup 2}
Date: June 3, 1993
Creator: Raja, R.
System: The UNT Digital Library