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The Theory of Hadronic Systems
This report briefly discusses progress on the following topics: isospin breaking in the pion-nucleon system; subthreshold amplitudes in the {pi}N system; neutron-proton charge-exchange; transparency in pion production; energy dependence of pion DCX; direct capture of pions into deeply bound atomic states; knock out of secondary components in the nucleus; radii of neutron distributions in nuclei; the hadronic double scattering operator; pion scattering and charge exchange from polarized nuclei; pion absorption in nuclei; modification of nucleon structure in nuclei; and antiproton annihilation in nuclei.
Date:
March 16, 1995
Creator:
Gibbs, William R.
Object Type:
Report
System:
The UNT Digital Library
RADIOASTRONOMY AND COMMUNICATION THROUGH SPACE. Brookhaven Lecture Series Number 1
The lecture contains discussions on developments in radioastronomy, requirements for space travel to a place 12 light years away, and speculations for communicating through space. (B.O.G.)
Date:
November 16, 1960
Creator:
Purcell, E.
Object Type:
Report
System:
The UNT Digital Library
Ultrasonic Digital Communication System for a Steel Wall Multipath Channel: Methods and Results
As of the development of this thesis, no commercially available products have been identified for the digital communication of instrumented data across a thick ({approx} 6 n.) steel wall using ultrasound. The specific goal of the current research is to investigate the application of methods for digital communication of instrumented data (i.e., temperature, voltage, etc.) across the wall of a steel pressure vessel. The acoustic transmission of data using ultrasonic transducers prevents the need to breach the wall of such a pressure vessel which could ultimately affect its safety or lifespan, or void the homogeneity of an experiment under test. Actual digital communication paradigms are introduced and implemented for the successful dissemination of data across such a wall utilizing solely an acoustic ultrasonic link. The first, dubbed the ''single-hop'' configuration, can communicate bursts of digital data one-way across the wall using the Differential Binary Phase-Shift Keying (DBPSK) modulation technique as fast as 500 bps. The second, dubbed the ''double-hop'' configuration, transmits a carrier into the vessel, modulates it, and retransmits it externally. Using a pulsed carrier with Pulse Amplitude Modulation (PAM), this technique can communicate digital data as fast as 500 bps. Using a CW carrier, Least Mean-Squared (LMS) adaptive …
Date:
February 16, 2006
Creator:
Murphy, TL
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
DSI3D-RCS: Theory manual
The DSI3D-RCS code is designed to numerically evaluate radar cross sections on complex objects by solving Maxwell`s curl equations in the time-domain and in three space dimensions. The code has been designed to run on the new parallel processing computers as well as on conventional serial computers. The DSI3D-RCS code is unique for the following reasons: Allows the use of unstructured non-orthogonal grids, allows a variety of cell or element types, reduces to be the Finite Difference Time Domain (FDTD) method when orthogonal grids are used, preserves charge or divergence locally (and globally), is conditionally stable, is non-dissipative, is accurate for non-orthogonal grids. This method is derived using a Discrete Surface Integration (DSI) technique. As formulated, the DSI technique can be used with essentially arbitrary unstructured grids composed of convex polyhedral cells. This implementation of the DSI algorithm allows the use of unstructured grids that are composed of combinations of non-orthogonal hexahedrons, tetrahedrons, triangular prisms and pyramids. This algorithm reduces to the conventional FDTD method when applied on a structured orthogonal hexahedral grid.
Date:
March 16, 1995
Creator:
Madsen, N.; Steich, D.; Cook, G. & Eme, B.
Object Type:
Report
System:
The UNT Digital Library
Coherent beam-beam effects, theory & observations
Current theoretical understanding of the coherent beam-beam effect as well as its experimental observations are discussed: conditions under which the coherent beambeam modes may appear, possibility of their resonant interaction (coherent resonances), stability of beam-beam oscillations in the presence of external impedances. A special attention is given to the coherent beam-beam modes of finite length bunches: the synchro-betatron coupling is shown to provide reduction in the coherent tuneshift and--at the synchrotron tune values smaller than the beam-beam parameter--Landau damping by overlapping synchrotron satellites.
Date:
July 16, 2003
Creator:
Alexahin, Yuri I
Object Type:
Article
System:
The UNT Digital Library
Task A: Theory of elementary particles. Annual report
Brief summaries of work are given in the following areas: grandunification, properties of neutrinos, rare decays of heavy quarks, jet production in hadron collisions (theory, structure, two-jet cross section, null-plane field theory), neutrino physics, and QCD calculations of annihilation of e{sup +}e{sup {minus}} into hadrons.
Date:
October 16, 1992
Creator:
Deshpande, N. G. & Soper, D. E.
Object Type:
Report
System:
The UNT Digital Library
Task A: Theory of elementary particles. [Inst. of Theoretical Science, Univ. of Oregon, Eugene, Oregon]
Brief summaries of work are given in the following areas: grandunification, properties of neutrinos, rare decays of heavy quarks, jet production in hadron collisions (theory, structure, two-jet cross section, null-plane field theory), neutrino physics, and QCD calculations of annihilation of e[sup +]e[sup [minus]] into hadrons.
Date:
October 16, 1992
Creator:
Deshpande, N.G. & Soper, D.E.
Object Type:
Report
System:
The UNT Digital Library
Physics of the 1 Teraflop RIKEN-BNL-Columbia QCD project. Proceedings of RIKEN BNL Research Center workshop: Volume 13
A workshop was held at the RIKEN-BNL Research Center on October 16, 1998, as part of the first anniversary celebration for the center. This meeting brought together the physicists from RIKEN-BNL, BNL and Columbia who are using the QCDSP (Quantum Chromodynamics on Digital Signal Processors) computer at the RIKEN-BNL Research Center for studies of QCD. Many of the talks in the workshop were devoted to domain wall fermions, a discretization of the continuum description of fermions which preserves the global symmetries of the continuum, even at finite lattice spacing. This formulation has been the subject of analytic investigation for some time and has reached the stage where large-scale simulations in QCD seem very promising. With the computational power available from the QCDSP computers, scientists are looking forward to an exciting time for numerical simulations of QCD.
Date:
October 16, 1998
Creator:
unknown
Object Type:
Article
System:
The UNT Digital Library
Flow Properties of Superfluid Systems of Fermions
The nonspherically symmetric solutions to the Bardeen-Cooper-Schrieffer theory are given a physical interpretation in terms of an anisotropic fluid model. These solutions have been used previously to predict a phase transition in liquid by He{sup 3} by Emery and Sessler and Anderson, Morel, Brueckner, and Soda. An investigation of the flow properties of such systems is made that involves the calculation of the effective mass for flow in a straight channel and the moment of inertia of a cylindrical container of the liquid. The angular dependent energy-gap characteristic of this type of theory leads to an effective mass for flow that depends on the angle between the axis of symmetry of the fluid and the direction of flow. It also vanishes as the absolute temperature tends to zero, although not as rapidly as for a spherically symmetric gap. The moment of inertia, when the symmetry direction for the fluid and the rotation axis are the same, is simply related to the mass for flow.
Date:
May 16, 1960
Creator:
Glassgold, A. E. & Sessler, A. M.
Object Type:
Report
System:
The UNT Digital Library
From neural and social cooperation to the global emergence of cognition
This article elaborates on a discussion of the emergence of intelligence via criticality as a consequence of locality breakdown, by using criticality for the foundation of a novel generation of game theory making the local interaction between players yield long-range effects.
Date:
June 16, 2015
Creator:
Grigolini, Paolo; Piccinni, Nicola; Svenkeson, Adam; Pramukkul, Pensri; Lambert, David & West, Bruce J.
Object Type:
Article
System:
The UNT Digital Library
Fundamental Statistical Descriptions of Plasma Turbulence in Magnetic Fields
A pedagogical review of the historical development and current status (as of early 2000) of systematic statistical theories of plasma turbulence is undertaken. Emphasis is on conceptual foundations and methodology, not practical applications. Particular attention is paid to equations and formalism appropriate to strongly magnetized, fully ionized plasmas. Extensive reference to the literature on neutral-fluid turbulence is made, but the unique properties and problems of plasmas are emphasized throughout. Discussions are given of quasilinear theory, weak-turbulence theory, resonance-broadening theory, and the clump algorithm. Those are developed independently, then shown to be special cases of the direct-interaction approximation (DIA), which provides a central focus for the article. Various methods of renormalized perturbation theory are described, then unified with the aid of the generating-functional formalism of Martin, Siggia, and Rose. A general expression for the renormalized dielectric function is deduced and discussed in detail. Modern approaches such as decimation and PDF methods are described. Derivations of DIA-based Markovian closures are discussed. The eddy-damped quasinormal Markovian closure is shown to be nonrealizable in the presence of waves, and a new realizable Markovian closure is presented. The test-field model and a realizable modification thereof are also summarized. Numerical solutions of various closures for some …
Date:
February 16, 2001
Creator:
Krommes, John A.
Object Type:
Report
System:
The UNT Digital Library
Subjective Functional Difficulties and Subjective Cognitive Decline in Older-Age Adults: Moderation by Age Cohorts and Mediation by Mentally Unhealthy Days
Article discusses how, despite the expected positive association between subjective functional difficulties (SFD) and subjective cognitive decline (SCD), their mediation by mentally unhealthy days (MUDs) is under-studied. This study examined the mediation effect of MUDs on the association between SFD and SCD by age cohorts’ moderation among older adults.
Date:
January 16, 2023
Creator:
Komalasari, Renata; Mpofu, Elias; Prybutok, Gayle & Ingman, Stanley R.
Object Type:
Article
System:
The UNT Digital Library
Physics Opportunities of a Fixed-Target Experiment using the LHC Beams
We outline the many physics opportunities offered by a multi-purpose fixed-target experiment using the proton and lead-ion beams of the LHC extracted by a bent crystal. In a proton run with the LHC 7-TeV beam, one can analyze pp, pd and pA collisions at center-of-mass energy {radical}s{sub NN} {approx_equal} 115 GeV and even higher using the Fermi motion of the nucleons in a nuclear target. In a lead run with a 2.76 TeV-per-nucleon beam, {radical}s{sub NN} is as high as 72 GeV. Bent crystals can be used to extract about 5 x 10{sup 8} protons/sec; the integrated luminosity over a year reaches 0.5 fb{sup -1} on a typical 1 cm-long target without nuclear species limitation. We emphasize that such an extraction mode does not alter the performance of the collider experiments at the LHC. By instrumenting the target-rapidity region, gluon and heavy-quark distributions of the proton and the neutron can be accessed at large x and even at x larger than unity in the nuclear case. Single diffractive physics and, for the first time, the large negative-xF domain can be accessed. The nuclear target-species versatility provides a unique opportunity to study nuclear matter versus the features of the hot and …
Date:
March 16, 2012
Creator:
Brodsky, S.J.; /SLAC; Fleuret, F.; Polytechnique, /Ecole; Hadjidakis, C.; Lansberg, J.P. et al.
Object Type:
Article
System:
The UNT Digital Library
Physics division annual report - October 2000.
This report summarizes the research performed in the past year in the Argonne Physics Division. The Division's programs include operation of ATLAS as a national heavy-ion user facility, nuclear structure and reaction research with beams of heavy ions, accelerator research and development especially in superconducting radio frequency technology, nuclear theory and medium energy nuclear physics. The Division took significant strides forward in its science and its initiatives for the future in the past year. Major progress was made in developing the concept and the technology for the future advanced facility of beams of short-lived nuclei, the Rare Isotope Accelerator. The scientific program capitalized on important instrumentation initiatives with key advances in nuclear science. In 1999, the nuclear science community adopted the Argonne concept for a multi-beam superconducting linear accelerator driver as the design of choice for the next major facility in the field a Rare Isotope Accelerator (RIA) as recommended by the Nuclear Science Advisory Committee's 1996 Long Range Plan. Argonne has made significant R&D progress on almost all aspects of the design concept including the fast gas catcher (to allow fast fragmentation beams to be stopped and reaccelerated) that in large part, defined the RIA concept the superconducting rf …
Date:
October 16, 2000
Creator:
Thayer, K.
Object Type:
Report
System:
The UNT Digital Library
Analytical Approach to Eigen-Emittance Evolution in Storage Rings
This dissertation develops the subject of beam evolution in storage rings with nearly uncoupled symplectic linear dynamics. Linear coupling and dissipative/diffusive processes are treated perturbatively. The beam distribution is assumed Gaussian and a function of the invariants. The development requires two pieces: the global invariants and the local stochastic processes which change the emittances, or averages of the invariants. A map based perturbation theory is described, providing explicit expressions for the invariants near each linear resonance, where small perturbations can have a large effect. Emittance evolution is determined by the damping and diffusion coefficients. The discussion is divided into the cases of uniform and non-uniform stochasticity, synchrotron radiation an example of the former and intrabeam scattering the latter. For the uniform case, the beam dynamics is captured by a global diffusion coefficient and damping decrement for each eigen-invariant. Explicit expressions for these quantities near coupling resonances are given. In many cases, they are simply related to the uncoupled values. Near a sum resonance, it is found that one of the damping decrements becomes negative, indicating an anti-damping instability. The formalism is applied to a number of examples, including synchrobetatron coupling caused by a crab cavity, a case of current interest …
Date:
May 16, 2006
Creator:
Nash, Boaz
Object Type:
Report
System:
The UNT Digital Library
Scattering of Positive Pions on Protons at 310 Mev: Recoil-Nucleon Polarization and Phase-Shift Analysis
None
Date:
September 16, 1960
Creator:
Foote, J. H.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Monte Carlo Calculations on Intranuclear Cascades
The basic assumption of the Serber model in the description of high- energy nuclear reactions is that the interactions of incident particles with complex nuclei can be described in terms of individual particle-particle collisions within the nucleus. Calculations were performed making use of the basic assumption of the Serber model, a more realistic nuclear model, recent cross-section data, and an exact statistical sampling technique. The sampling technique has not been used previously in calculations of this type. Calculations were performed for incident e (as Fe/sup 59 /sup +/, e (as Fe/sup 59 /sup -/, neutrons, and protons on nuclei from lithium to uranium. The energy range of the incident particles varied from about 50 to 350 Mev, i.e., the energy region in which pion production is not likely. Free-particle cross sections were used in determining the collisions within the nucleus, and statistical sampling techniques were used throughout, The problem was coded for the IBM-7090. Extensive comparisons with experiment were made and the results indicate that the calculation can be used to predict most of the cascade data for incident nucleons on complex nuclei, but only the gross features of the data are predictable for incident pions on nuclei. The effects …
Date:
May 16, 1963
Creator:
Bertini, H. W.
Object Type:
Thesis or Dissertation
System:
The UNT Digital Library
Experimental and Analytical Reactivity Studies of Clean Critical Stainless Steel Cores
ABS>The results are presented of critical water height measurements made on close-packed lattices of Spert III, highly enriched, plate-type, stainless- steel-clad fuel elements. Experiments were conducted with cores containing no control rods and with cores containing a single, fully-inserted control rod. The "clean critical" data obtained in these experiments were used to test the validity of various aspects of a four-group, diffusion theory analysis of the full scale Spert III reactor. The results of the analyses of the rod-free and single-rodded critical lattices show that for such stainless steel cores k/sub eff/ can be calculated to within 1% DELTA k and that the Spert III control rod worth is calculable to a few tenths % DELTA k. (auth)
Date:
June 16, 1961
Creator:
Spano, A. H.
Object Type:
Report
System:
The UNT Digital Library
Projections of transport scaling laws for small toroidal reactors
Transport in present day Spheromaks is dominated by impurity radiation. Fortunately, this is largely from oxygen and carbon, not metal vapor from the walls of the vessel on plasma guns and it is expected this loss can be eliminated by improved technique. The formation and gross MHD stability properties of these plasmas are quite well understood and so the reactor predictions depend on estimates of the energy loss rates from the plasma. In the absence of significant experimental data one is driven to consider other related devices. Tokamaks show classical ion transport, scaling with 1/B/sup 2/, but anomalous electron transport which is very insensitive to magnetic field, the well known Alcator scaling. The scaling of the Spheromak to a reactor size still produces favorable Q values with these pessimistic results. The reactor is small, with power output in the 10 to 50 MW range, but this could be deployed as a multiple unit power station, with good reliability due to the duplication, or as a small power unit for a ship or remote site. It also makes an attractive test reactor for the near term.
Date:
November 16, 1981
Creator:
McNamara, B.
Object Type:
Article
System:
The UNT Digital Library
Analysis of time- and space-resolved Na-, Ne-, and F-like emission from a laser-produced bromine plasma
Advances in the efficiency and accuracy of computational atomic physics and collisional radiative modeling promise to place the analysis and diagnostic application of L-shell emission on a par with the simpler K-shell regime. Coincident improvements in spectroscopic plasma measurements yield optically thin emission spectra from small, homogeneous regions of plasma, localized both in space and time. Together, these developments can severely test models for high-density, high-temperature plasma formation and evolution, and non-LTE atomic kinetics. In this paper we present highly resolved measurements of n=3 to n=2 X-ray line emission from a laser-produced bromine micro-dot plasma. The emission is both space- and time-resolved, allowing us to apply simple, steady-state, 0-dimensional spectroscopic models to the analysis. These relativistic, multi-configurational, distorted wave collisional-radiative models were created using the HULLAC atomic physics package. Using these models, we have analyzed the F-like, Ne-like and Na-like (satellite) spectra with respect to temperature, density and charge-state distribution. This procedure leads to a full characterization of the plasma conditions. 9 refs., 3 figs.
Date:
January 16, 1991
Creator:
Goldstein, W.H.; Young, B.K.F.; Osterheld, A.L.; Stewart, R.E.; Walling, R.S. (Lawrence Livermore National Lab., CA (USA)); Bar-Shalom, A. (Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev) et al.
Object Type:
Article
System:
The UNT Digital Library
Matter oscillations and solar neutrinos: A review of the MSW (Mikheyev-Smirnov-Wolfenstein) effect
We review the theory of the Mikheyev-Smirnov-Wolfenstein effect, in which matter oscillations can greatly enhance ''in vacuo'' neutrino oscillations, and we examine its consequences for the solar neutrino problem. Using a two-flavor model, we discuss the solutions in the ..delta..m/sup 2/-sin/sup 2/2THETA parameter space for the /sup 37/Cl experiment, and describe their predictions for the /sup 71/Ga experiment and for the spectrum of electron-neutrinos arriving at earth. We also comment on the three-flavor case.
Date:
July 16, 1986
Creator:
Rosen, S. P. & Gelb, J. M.
Object Type:
Article
System:
The UNT Digital Library
Technical and analytical support to the ARPA Artificial Neural Network Technology Program
Strategic Analysis (SA) has provided ongoing work for the Advanced Research Projects Agency (ARPA) Artificial Neural Network (ANN) technology program. This effort provides technical and analytical support to the ARPA ANN technology program in support of the following information areas of interest: (1) Alternative approaches for application of ANN technology, hardware approaches that utilize the inherent massive parallelism of ANN technology, and novel ANN theory and modeling analyses. (2) Promising military applications for ANN technology. (3) Measures to use in judging success of ANN technology research and development. (4) Alternative strategies for ARPA involvement in ANN technology R&D. These objectives were accomplished through the development of novel information management tools, strong SA knowledge base, and effective communication with contractors, agents, and other program participants. These goals have been realized. Through enhanced tracking and coordination of research, the ANN program is healthy and recharged for future technological breakthroughs.
Date:
September 16, 1995
Creator:
unknown
Object Type:
Report
System:
The UNT Digital Library
Specific activity of the NPR primary coolant loop
In coolant system such as NPR's, the coolant activity level increase with each succeeding pass through the reactor flux until a saturation limit is reached. Therefore, the activity level of the NPR coolant system will be much higher than that of the old reactor once-through systems. This report is the determination of the specific activities (disintegrations/cc{center dot}sec) of the various coolant impurities which determine the total activity of the coolant system. 10 refs., 13 figs., 2 tabs.
Date:
February 16, 1961
Creator:
Bitz, D.A.
Object Type:
Report
System:
The UNT Digital Library
Status of Issues in U.S. Edge-Plasma Research and Priority Topics for the Next Five Years
The Edge Coordinating Committee (ECC) was formed in July 14-15, 2004 when OFES Theory Team invited 14 plasma researchers to a two-day meeting in Germantown, MD to discuss the state of edge-plasma research in the U.S. with a focus on theory and modeling (see http://www.mfescience.org/ecc/ ecc/). At that time, OFES tasked the ECC with providing, in about a six month period, a report on the present status of key issues in this area together with a roadmap of what range of activities should be undertaken in the next five years to resolve these issues. This document is a response to that charge. Future edge-plasma research described here is assumed to fit into a budget constraint of a ''flat budget,'' with some additional activities cited for budget increases of as much as 50%. To obtain some measure of the relative fraction of OFES Theory funding presently devoted to edge plasma research, the OFES Theory Team informally surveyed funded work they support in this area at National Labs, Universities, and industry. John Mandrekas reported to us that approximately 10% of the present budget goes to edge-physics areas at 10 institutions, for a total of {approx}$2.5M each year. While not explicitly estimated, we …
Date:
March 16, 2005
Creator:
Bateman, G.; Chang, C.; Fenstermacher, M.; Guzdar, P.; Hahm, T. S.; Krasheninnikov, S. et al.
Object Type:
Report
System:
The UNT Digital Library