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in subjects: "Interaction Range"

open access

Problem of long-range forces in the computer simulation of condensed media

Simulation (both Monte Carlo and molecular dynamical) has become a powerful tool in the study of classical systems of particles interacting with short-range pair potentials. For systems involving long-range forces (e.g., Coulombic, dipolar, hydrodynamic) it is a different story. Relating infinite-system properties to the results of computer simulation involving relatively small numbers of particles, periodically replicated, raises difficult and challenging problems. The purpose of the workshop … more

Date: July 1, 1980

Creator: Ceperely, D. (ed.)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Exclusive processes and hadron dynamics at short distances

The predictions of perturbative QCD for a number of areas of hadron dynamics are discussed, including exclusive processes at large momentum transfer, the endpoint behavior of hadronic structure functions, and the Fock state structure of hadron wave functions, especially their behavior at short distances. New results for exclusive two-photon processes, the normalization of high-twist contributions to the meson structure function, and the calculation of the valence Fock state probability of the p… more

Date: September 1, 1980

Creator: Brodsky, S.J. & Lepage, G.P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Long-range and head-on beam-beam compensation studies in RHIC with lessons for the LHC

Long-range as well as head-on beam-beam effects are expected to limit the LHC performance with design parameters. They are also important consideration for the LHC upgrades. To mitigate long-range effects, current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and ana… more

Date: January 12, 2009

Creator: Fischer, W.; Luo, Y.; Abreu, N.; Calaga, R.; Montag, C.; Robert-Demolaize, G. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Simulation of Flow and Transport at the Micro (Pore) Scale

An important problem in porous media involves the ability of micron and submicron-sized biological particles such as viruses or bacteria to move in groundwater systems through geologic media characterized by rock or mixed gravel, clay and sand materials. Current simulation capabilities require properly upscaled (continuum) models of colloidal filtration and adsorption to augment existing theories of fluid flow and chemical transport. Practical models typically address flow and transport behavio… more

Date: April 5, 2007

Creator: Trebotich, D & Miller, G H

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Petite unification: an alternative viewpoint

It is assumed that at some distance scale, not too many orders of magnitude less than the compton wavelength of intermediate bosons W/sup + -/ and Z/sup 0/, the SU(3)/sub c/ x SU(2)/sub L/ x U(1)/sub Y/ gauge theory, characterized by three coupling constants, becomes embedded in a gauge theory G/sub S/ x G/sub W/ characterized by only two coupling constants, g/sub S/ and g/sub W/. The strong group G/sub S/ and weak group G/sub W/ are assumed each to be either simple or pseudo-simple i.e. a dire… more

Date: May 1, 1981

Creator: Hung, P.Q.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quantum chromodynamics and the dynamics of hadrons. [Review, bound state, perturbation theory]

The application of perturbative quantum chromodynamics to the dynamics of hadrons at short distance is reviewed, with particular emphasis on the role of the hadronic bound state. A number of new applications are discussed, including the modification to QCD scaling violations in structure functions due to hadronic binding; a discussion of coherence and binding corrections to the gluon and sea-quark distributions; QCD radiative corrections to dimensional counting rules for exclusive processes and… more

Date: March 1, 1979

Creator: Brodsky, Stanley J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

What can be learned with fast neutrons

The DOE/NSF Nuclear Science Advisory Committee (NSAC) is preparing a new Long Range Plan for the development of nuclear science. This document, written as input to the Long Range Plan subcommittees; describes a number of ways that experiments with incident neutrons impact on outstanding problems in nuclear reactions and spectroscopy. It is argued that major extensions of present capabilities are required to carry out these experiments.

Date: June 1, 1983

Creator: Dietrich, F.S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Optical model calculations of nucleon interactions with /sup 93/Nb, from 10 keV up to 50 MeV. [Spherical potential]

The neutron spherical optical potential is determined following the SPRT method by a fit to strength functions, scattering radius, total cross section and neutron elastic scattering data. Comparison to the potential obtained with existing proton scattering data, (p,p) (p,n), provides a basis for the determination of the complex symmetry term of the optical potential. Calculations using the J.L.M. optical model will be also presented and discussed. 18 references.

Date: January 1, 1979

Creator: Lagrange, C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Inclusive study of 200 GeV/c pi-neon interactions

200 GeV/c pi-neon interactions are studied in the Fermilab 30 inch bubble chamber which was filled with a neon - hydrogen mixture (31 molar % neon). Scan results and measurements of a representative event sample yield proton, gamma and pion multiplicities and single particle spectra. R was measured to be 1.21 +- 0.05 for both pi +- and pi/sup 0/. Nearly identical to lower energy measurements, R is strongly dependent on the number of observed protons in the event. KNO scaling is observed for the… more

Date: January 1, 1980

Creator: Band, H R

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Weak interactions. [SU(2) symmetry, electromagnetic correction]

The weak interaction is studied from a phenomenological viewpoint. The aim is to describe the present situation concisely, using a minimal number of theoretical hypotheses. First, charged-current phenomenology is discussed, then neutral-current phenomenology. This can all be described in terms of a global SU(2) symmetry plus an electromagnetic correction. The intermediate-boson hypothesis is then introduced, and lower bounds are inferred on the range of the weak force. 18 references. (JFP)

Date: June 1, 1978

Creator: Bjorken, J. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Tritium production in a sphere of /sup 6/LiD irradiated by 14-MeV neutrons

The specific production of tritium in samples of /sup 6/LiH and /sup 7/LiH embedded in a 600-mm-diam sphere of /sup 6/LiD irradiated by a central source of 14-MeV neutrons was determined by measuring the activity of the hydrogen evolved from the samples of each isotope at each of five different radii in the /sup 6/LiD assembly. The entire process of decomposing the LiH, transferring the evolved gas into counters, and determining the decay rate was standardized by processing LiH samples irradiat… more

Date: October 1, 1978

Creator: Hemmendinger, A.; Ragan, C.E.; Shunk, E.R.; Ellis, A.N.; Anaya, J.M. & Wallace, J.M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Chromogravity explains "strong gravity"

In this paper the authors deal with the question of gravitational type interactions in the case of strong interaction phenomena. They present arguments which indicate that it is not necessary to invoke a gravity type interaction into QCD in order to account for observed phenomena. They argue that the gravitational type phenomena discussed in previous work is a manifestation of a class of Feynmann diagrams. These seem to generate an analog to gravity, a J=2 {open_quotes}chromograviton{close_quot… more

Date: March 1, 1993

Creator: Ne`eman, Y. & Sijacki, D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Critical phenomena in thick films of a binary liquid mixture

The first experimental data on the behavior of a critical system as it approaches two dimensionality are presented. Measurements of the bulk coexistence curve by use of refractive index techniques were done on the binary fluid mixture methanol--cyclohexane. These measurements gave the critical exponent ..beta.. = 0.326 +- 0.003, which agrees with recent Ising-model calculations. This same binary fluid mixture was then constrained between two highly reflective, optically flat pieces of fused sil… more

Date: January 1, 1976

Creator: Jacobs, D. T.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

RHIC BBLR measurements in 2009

Long range beam-beam experiments were conducted during the Run 2009 in the Yellow and the Blue beams of the RHIC accelerator with DC wires. The effects of a long-range interaction with a DC wire on colliding and non-colliding bunches with the aid of beam losses, orbits, tunes were studied. Results from distance scans and an attempt to compensate a long-range interaction with a DC wire is presented. Two DC wires in the vertical plane were installed in the RHIC accelerator in 2006 with the aim of… more

Date: May 23, 2010

Creator: Calaga, R.; Robert-Demolaize, G. & Fischer, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Long-Range And Head-On Beam-Beam Compensation Studies in RHIC With Lessons for the LHC

Long-range as well as head-on beam-beam effects are expected to limit the LHC performance with design parameters. They are are also important consideration for the LHC upgrades. To mitigate long-range effects, current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and… more

Date: November 28, 2011

Creator: Fischer, W.; Luo, Y.; Abreu, N.; Calaga, R.; Montag, C.; Robert-Demolaize, G. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Beam-beam simulation code BBSIM for particle accelerators

A highly efficient, fully parallelized, six-dimensional tracking model for simulating interactions of colliding hadron beams in high energy ring colliders and simulating schemes for mitigating their effects is described. The model uses the weak-strong approximation for calculating the head-on interactions when the test beam has lower intensity than the other beam, a look-up table for the efficient calculation of long-range beam-beam forces, and a self-consistent Poisson solver when both beams h… more

Date: January 1, 2011

Creator: Kim, Hyung J. & Sen, Tanaji

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

LHC beam-beam compensation studies at RHIC

Long-range and head-on beam-beam effects are expected to limit the LHC performance with design parameters. To mitigate long-range effects current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and analytical treatments. To reduce the head-on beam-beam effect electron … more

Date: May 4, 2009

Creator: Fischer, W.; Abreu, N.; Calaga, R.; Robert-Demolaize, G.; Luo, Y. & Montag, C.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Molecular Simulation of Phase Equilibria for Complex Fluids

The general area of this project was the development and application of novel molecular simulation methods for prediction of thermodynamic and structural properties of complex polymeric, surfactant and ionic fluids. Over this project period, we have made considerable progress in developing novel algorithms to meet the computational challenges presented by the strong or long-range interactions in these systems and have generated data for well-defined mod-els that can be used to test theories and… more

Date: September 9, 2009

Creator: Panagiotopoulos, Athanassios Z.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Tevatron Electron Lenses: Design and Operation

Fermilab's Tevatron is currently the world's highest energy accelerator in which tightly focused beams of 980 GeV protons and antiprotons collide at two dedicated interaction points (IPs). Both beams share the same beam pipe and magnet aperture and, in order to avoid multiple detrimental head-on collisions, the beams are placed on separated orbits everywhere except the main IPs by using high-voltage (HV) electrostatic separators. The electromagnetic beam-beam interaction at the main IPs togethe… more

Date: September 12, 2011

Creator: Shiltsev, Vladimir; Bishofberger, Kip; Kamerdzhiev, Vsevolod; Kozub, Sergei; Kufer, Matthew; Kuznetsov, Gennady et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Long-Range Lepton Flavor Interactions and Neutrino Oscillations

Recent results from the MINOS accelerator neutrino experiment suggest a possible difference between {nu}{sub {mu}} and {bar {nu}}{sub {mu}} disappearance oscillation parameters, which one may ascribe to a new long distance potential acting on neutrinos. As a specific example, we consider a model with gauged B - L{sub e} - 2L{sub {tau}} number which contains an extremely light new vector boson, m{sub Z}, < 10{sup -18} eV and extraordinarily weak coupling {alpha}{prime} {approx}< 10{sup -52… more

Date: March 31, 2011

Creator: Davoudiasl, H.; Lee, H. S. & Marciano, W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Optical model calculations at Rensselaer Polytechnic Institute

No Description Available.

Date: January 1, 1974

Creator: Sierra, J. M. & Turinsky, P. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Theory for dynamical self arrest and gelation in microemulsions and the block copolymer systems

The main purpose of this work is to investigate the glassy behavior of microemulsions and block copolymers. The origin of glassy behavior in microemulsions and block copolymers is frustration due to a competition between short-range interaction and long range interaction. According to the charge frustrated Ising model, the competition between ferromagnetic interaction and antiferromagnetic interaction is the origin of frustration in microemulsions. The competition between entropic effects and s… more

Date: May 1, 2005

Creator: Wu, Sangwook

Item Type: Thesis or Dissertation

Partner: UNT Libraries Government Documents Department

open access

Studies of beam-beam interactions in Run IIa at the Tevatron

We discuss the impact of the beam-beam interactions on Run IIa operation at the design parameters. We focus on the seventy long-range interactions which primarily determine the stable region in phase space and limit the lifetime. We discuss recent improvements in lifetime at injection and dynamic aperture calculations at collision.

Date: July 2, 2002

Creator: al., Tanaji Sen et

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New aspects of beam-beam interactions in hadron colliders

Beam-beam phenomena have until now limited the beam currents and luminosity achievable in the Tevatron. injected proton currents are about ten times larger than the anti-proton currents so beam-beam effects have largely acted on the anti-protons and at all stages of the operational cycle. The effects of the anti-protons on the protons have until now been relatively benign but that may change at higher anti-proton currents. After 36 bunches of protons are injected and placed on the proton helix,… more

Date: June 2, 2003

Creator: Sen, Tanaji

Item Type: Article

Partner: UNT Libraries Government Documents Department