9 Matching Results

Results open in a new window/tab.

New possibilities for exotic hadrons (open access)

New possibilities for exotic hadrons

New theoretical ideas and experimental evidence for exotic hadrons are presented. A new exciting candidate is an anticharmed baryon; i.e., a bound state of a nucleon and an F (now called D3). New experimental evidence for four-quark exotic mesons presented at this conference is discussed. The confusion in the E-iota region and the pseudoscalar spectrum still await further experimental clarification.
Date: May 12, 1987
Creator: Lipkin, Harry J.
System: The UNT Digital Library
A neutron portal monitor for vehicles (open access)

A neutron portal monitor for vehicles

We have designed and built a portal vehicle monitoring systems for detecting neutron-emitting special nuclear material (SNM) such as plutonium. Monte Carlo calculations were used to optimize the design of the 15-cm-deep x 122-cm-high x 244-cm-long detector chambers, which utilize /sup 3/He proportional counters inside a hollow polyethylene box. Results for a variety of parametric studies, including polyethylene thickness and detector number, are described. Our experimental measurements are in good agreement with the computer calculations. The monitor's decision logic uses the Sequential Probability Ratio Test (SPRT) on Poisson distributed counting data, which is superior to other statistical tests in many applications. We performed computer simulations of the SPRT logic to determine expected false-positive decision rates. A controller unit of our design that uses this SPRT was built commercially. The cost of the complete monitoring system is similar to that of vehicle portal monitors that detect gamma rays. This new neutron monitor can serve as an addition to standard gamma-ray vehicle portals or as a stand-alone portal monitor in particular safeguards monitoring situations. The monitor is being tested at Los Alamos and is scheduled for in-plant evaluation of another DOE facility in 1987. 7 refs.
Date: July 12, 1987
Creator: Coop, K. L.; Fehlau, P. E. & Atwater, H. F.
System: The UNT Digital Library
Particle simulation of intense electron cyclotron heating and beat-wave current drive (open access)

Particle simulation of intense electron cyclotron heating and beat-wave current drive

High-power free-electron lasers make new methods possible for heating plasmas and driving current in toroidal plasmas with electromagnetic waves. We have undertaken particle simulation studies with one and two dimensional, relativistic particle simulation codes of intense pulsed electron cyclotron heating and beat-wave current drive. The particle simulation methods here are conventional: the algorithms are time-centered, second-order-accurate, explicit, leap-frog difference schemes. The use of conventional methods restricts the range of space and time scales to be relatively compact in the problems addressed. Nevertheless, experimentally relevant simulations have been performed. 10 refs., 2 figs.
Date: October 12, 1987
Creator: Cohen, B.I.
System: The UNT Digital Library
Heterodyne phase shift diagnostic for measuring atomic vapor density (open access)

Heterodyne phase shift diagnostic for measuring atomic vapor density

We describe a technique for atomic density measurements. We generate and recombine frequency shifted laser beams producing beat signals on reference and signal detectors. Opacity in the signal detector leg is proportional to the phase difference between detector signals. 4 refs., 2 figs.
Date: November 12, 1987
Creator: Crane, J. K.; Paisner, J. A.; Johnson, M. A.; Story, T. W.; Barclay, C.; George, J. D. et al.
System: The UNT Digital Library
Currents in ATF (open access)

Currents in ATF

This paper contains viewgraphs on the existence of currents in ATF Torsatron. Current sources like bootstrap, Pfirsch-Schluter, beam driven and flux conserving are investigated and suggestions on minimization are given. (LSP)
Date: November 12, 1987
Creator: Carreras, B. A.; Shaing, K. C.; Dominguez, N.; Lynch, V. E. & Tolliver, J. S.
System: The UNT Digital Library
Compositeness and QCD at the SSC (open access)

Compositeness and QCD at the SSC

Compositeness may be signaled by an increase in the production of high transverse momentum hadronic jet pairs or lepton pairs. The hadronic jet signal competes with the QCD production of jets, a subject of interest in its own right. Tests of perturbative QCD at the SSC will be of special interest because the calculations are expected to be quite reliable. Studies show that compositeness up to a scale of 20 to 35 TeV would be detected in hadronic jets at the SSC. Leptonic evidence would be discovered for scales up to 10 to 20 TeV. The charge asymmetry for leptons would provide information on the nature of the compositeness interaction. Calorimetry will play a crucial role in the detection of compositeness in the hadronic jet signal. Deviations from an e/h response of 1 could mask the effect. The backgrounds for lepton pair production seem manageable. 30 refs., 19 figs., 10 tabs.
Date: October 12, 1987
Creator: Barnes, V.; Blumenfeld, B.; Cahn, R.; Chivukula, S.; Ellis, S.; Freeman, J. et al.
System: The UNT Digital Library
Oxygen-induced reactions at 60 A GeV and 200 A GeV studied by calorimetry (open access)

Oxygen-induced reactions at 60 A GeV and 200 A GeV studied by calorimetry

Results based on calorimetric measurements are presented from reactions of 60 A GeV and 200 A GeV /sup 16/O projectiles with C, Cu, Ag, and Au nuclei. Minimum-bias cross sections are discussed. Energy spectra measured at zero degrees and transverse-energy distributions for the pseudorapidity range 2.4 less than or equal to eta less than or equal to 5.5 are shown. An analysis of the average transverse energy in terms of the number of participating nucleons and the number of binary nucleon-nucleon collision is presented. Estimates of nuclear stopping and of attained energy densities are made. 22 refs., 6 figs., 3 tabs.
Date: November 12, 1987
Creator: Sorensen, S.P.; Albrecht, R.; Awes, T.C.; Baktash, C.; Beckmann, P.; Berger, F. et al.
System: The UNT Digital Library
Effective nonrenormalizable theories at one loop (open access)

Effective nonrenormalizable theories at one loop

The paper focuses on a nonrenormalizable theory that is more closely related to those suggested by superstrings, namely a gauged nonlinear delta-model, but one which can also be obtained analytically in a particular limit of a parameter (m/sub H/ ..-->.. infinity) of the standard, renormalizable electroweak theory. This will provide another laboratory for testing the validity of calculations using the effective theory. We find (as for certain superstring inspired models to be discussed later) features similar to those for the Fermi theory: quadratic divergences can be reinterpreted as renormalizations, while new terms are generated at the level of logarithmic divergences. Also introduced in the context of more familiar physics are notions such as scalar metric, scalar curvature and nonlinear symmetries, that play an important role in formal aspects of string theories. 58 refs., 12 figs.
Date: October 12, 1987
Creator: Gaillard, M. K.
System: The UNT Digital Library
Foreign Students Fueled 2% Rise in 1985 Graduate Science and Engineering Enrollment (open access)

Foreign Students Fueled 2% Rise in 1985 Graduate Science and Engineering Enrollment

Article from the National Science Foundation, noting that the 2% rise in 1985 graduate science and engineering enrollment was due to foreign students.
Date: June 12, 1987
Creator: National Science Foundation
System: The UNT Digital Library