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Nucleon-nucleon data

Description: This is the final report of a one-year, Laboratory Directed Research and Development (LDRD) project at Los Alamos National Laboratory (LANL). This work completes the determination of the nucleon-nucleon (NN) scattering amplitudes from 485 to 800 MeV. The data set is completed by the publication of two papers. These new data have a precision better than 1% and an absolute accuracy about 1%, which is generally an order of magnitude better than previous data. The NN data set is now complete and consistent. The set of spin-dependent NN-scattering amplitudes is now well determined up to 800 MeV.
Date: October 1, 1997
Creator: McNaughton, M.W.; Gulmez, E. & Whitten, C.A.
Partner: UNT Libraries Government Documents Department

Charge independence, charge symmetry breaking in the S-wave nucleon-nucleon interaction, and renormalization

Description: We study the interplay between charge symmetry breaking and renormalization in the NN system for S-waves. We find a set of universality relations which disentangle explicitly the known long distance dynamics from low energy parameters and extend them to the Coulomb case. We analyze within such an approach the One-Boson-Exchange potential and the theoretical conditions which allow to relate the proton-neutron, proton-proton and neutron-neutron scattering observables without the introduction of extra new parameters and providing good phenomenological success.
Date: February 1, 2012
Creator: Alvaro Calle Cordon,Manuel Pavon Valderrama,Enrique Ruiz Arriola
Partner: UNT Libraries Government Documents Department

Euclidean responses of 4He at high momentum transfer

Description: The Euclidean proton and nucleon responses of <sup>4</sup>He at <I>q</I>=10 fm<sup>-1</sup>, evaluated with the correlated Glauber approximation using a realistic nucleon-nucleon interaction and nonrelativistic kinematics, are compared to those obtained from the Green's function Monte Carlo approach. The results show that final state interactions play a crucial role even at this large value of q, and that their effect can be quantitatively accounted for with the correlated Glauber approximation.
Date: July 1, 1995
Creator: Carlson, Joseph; Benhar, Omar; Schiavilla, Rocco & Pandharipande, Vijay
Partner: UNT Libraries Government Documents Department

Investigations of the dynamics and electromagnetic interactions of few-body systems. Progress report, June 30, 1994--September 30, 1995

Description: This progress report summarizes the work of The George Washington University (GW) nuclear theory group during the period 1 July 1994 - 30 September 1995 under DOE Grant No. DE-FG02-95-ER40907 mainly dealing with photonuclear reactions and few-body problems of nuclei. This report contains: papers published or in press, submitted for publication, and in preparation; invited talks at conferences and meetings; invited talks at universities and laboratories; contributed papers or abstracts at conferences; visitors to the group; and research progress by topic.
Date: October 1, 1995
Creator: Lehman, D.R.
Partner: UNT Libraries Government Documents Department

[SSC subsystem proposal for pre-shower and Shower Maximum Detectors]. Final report

Description: The basic purpose of this project was to devise low-cost photodetectors and arrays with large dynamic range capable of high-rate, radiation-resistant operation in multi-TeV hadron colliders. This project`s particular application was changed from the Superconducting Super Collider`s SDC detector to the Large Hadron Collider`s CMS after the Superconducting Super Collider project was cancelled. This report describes development and testing of photodetectors, and contains both a table summarizing the properties of different photodetectors and a paper on the performance of an avalanche photodiode photomultiplier tube tested at the CERN PS.
Date: December 31, 1994
Partner: UNT Libraries Government Documents Department

Two-pion exchange potential and the {pi}N amplitude

Description: The authors discuss the two-pion exchange potential which emerges from a box diagram with one nucleon (the spectator) restricted to its mass shell, and the other nucleon line replaced by a subtracted, covariant {pi}N scattering amplitude which includes {Delta}, Roper, and D{sub 13} isobars, as well as contact terms and off-shell (non-pole) dressed nucleon terms. The {pi}N amplitude satisfies chiral symmetry constraints and fits {pi}N data below {approximately} 700 MeV pion energy. They find that this TPE potential can be well approximated by the exchange of an effective sigma and delta meson, with parameters close to the ones used in one-boson-exchange models that fit NN data below the pion production threshold.
Date: May 1, 1996
Creator: Pena, M. T.; Gross, Franz & Surya, Yohanes
Partner: UNT Libraries Government Documents Department

Interaction, currents and the electromagnetic structure of light nuclei

Description: The authors discuss the traditional model of the nucleus as a system of nucleons interacting via effective interactions and currents, and present results obtained within this framework for the electromagnetic structure of the ground- and low-lying-states of A=3-6 nuclei.
Date: June 1, 1998
Creator: L.E. Marcucci, R. Schiavilla
Partner: UNT Libraries Government Documents Department

Ab Initio Study of 40Ca with an Importance Truncated No-Core Shell Model

Description: We propose an importance truncation scheme for the no-core shell model, which enables converged calculations for nuclei well beyond the p-shell. It is based on an a priori measure for the importance of individual basis states constructed by means of many-body perturbation theory. Only the physically relevant states of the no-core model space are considered, which leads to a dramatic reduction of the basis dimension. We analyze the validity and efficiency of this truncation scheme using different realistic nucleon-nucleon interactions and compare to conventional no-core shell model calculations for {sup 4}He and {sup 16}O. Then, we present the first converged calculations for the ground state of {sup 40}Ca within no-core model spaces including up to 16{h_bar}{Omega}-excitations using realistic low-momentum interactions. The scheme is universal and can be easily applied to other quantum many-body problems.
Date: May 22, 2007
Creator: Roth, R & Navratil, P
Partner: UNT Libraries Government Documents Department

Predictive model of nucleon-nucleus scattering cross sections

Description: Nucleon total reaction and neutron total cross sections as well as differential (including spin) observables from 25 to 300 MeV for stable nuclei from 6Li to 238U have been predicted that are in good agreement with measured data. Those predictions have been made using non-local, energy dependent, and complex optical potentials in coordinate space formed by full folding of effective nucleon-nucleon interactions with realistic nuclear ground state densities. By inverse kinematics the same model prescription describes exotic (radioactive) nuclei scattering from hydrogen as a target and the results reveal the extended (neutron) distributions such nuclei can have.
Date: January 1, 2001
Creator: Amos, K. (Ken); Deb, P. (Pradip); Karataglidis, S. (Steven) & Madland, D. G.
Partner: UNT Libraries Government Documents Department

Recent status in the search for the quark-gluon plasma

Description: The author reviews recent experimental results in the search for the quark-gluon plasma. Because the magnitudes of many signals for the plasma are directly proportional to the reaction cross sections, the author examines the corrections to the commonly used lowest-order cross sections. The author finds that the corrections are often significant and should be properly taken into account. The use of dileptons and photons with large transverse momenta is suggested as a means to study the boundary of the quark-gluon plasma.
Date: February 1, 1995
Creator: Wong, Cheuk-Yin
Partner: UNT Libraries Government Documents Department

High energy nuclear collisions

Description: This presentation covers three broad topics: a brief introduction to the field of nucleus-nucleus collisions at relativistic energies; a discussion of several topics illustrating what`s been learned after more than a decade of fixed target experiments; and an indication of what the future may bring at the Relativistic Heavy Ion Collider (RHIC) under construction at the Brookhaven National Laboratory (BNL) and at the Large Hadron Collider (LHC) planned at CERN.
Date: January 1, 1998
Creator: Plasil, F.
Partner: UNT Libraries Government Documents Department

Quantum Monte Carlo calculations for light nuclei

Description: Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 have been made using a realistic Hamiltonian that fits NN scattering data. Results for more than two dozen different (J{sup {pi}}, T) p-shell states, not counting isobaric analogs, have been obtained. The known excitation spectra of all the nuclei are reproduced reasonably well. Density and momentum distributions and various electromagnetic moments and form factors have also been computed. These are the first microscopic calculations that directly produce nuclear shell structure from realistic NN interactions.
Date: October 1, 1997
Creator: Wiringa, R.B.
Partner: UNT Libraries Government Documents Department

Unresolved questions in J/{psi} production and propagation in nuclei

Description: In order to understand the J/{psi} suppression arising from the possible occurrence of the quark-gluon plasma in high-energy heavy-ion collisions, it is necessary to have a comprehensive picture how the J/{psi} and its precursors are produced, what their properties after production are, and how the J/{psi} and its precursors propagate inside nuclear matter. There are unresolved questions in the descriptions of J/{psi} production and propagation. The author outlines some of these questions and discusses the approaches for their resolution.
Date: November 1, 1998
Creator: Wong, C.Y.
Partner: UNT Libraries Government Documents Department

Lattice Gauge Theory - QCD from quarks to hadrons

Description: Lattice Gauge Theory enables an ab initio study of the low-energy properties of Quantum Chromodynamics, the theory of the strong interaction. The author begins these lectures by presenting the lattice formulation of QCD, and then outline the benchmark calculation of lattice QCD, the light-hadron spectrum. He then proceeds to explore the predictive power of lattice QCD, in particular as it pertains to hadronic physics. He discusses the spectrum of glueballs, exotics and excited states, before investigating the study of form factors and structure functions. He concludes by showing how lattice QCD can be used to study multi-hadron systems, and in particular provide insight into the nucleon-nucleon interaction.
Date: June 1, 2000
Creator: Richards, D.G.
Partner: UNT Libraries Government Documents Department

NN interactions in QCD: Old and new techniques

Description: Since QCD is believed to be the underlying theory of the strong interaction, it is appropriate to study techniques that take into account more features of its rich and complex structure. The authors begin by discussing aspects of physics that are ill-reproduced by the usual one- or two-meson exchange approaches and identify the source of the deficiencies of these models. They then reveal promising methods for curing some of these ills, such as new quark potential models, baryon chiral perturbation theory, soluble strongly-interacting field theories, and large N{sub c} QCD.
Date: September 1998
Creator: Lebed, Richard
Partner: UNT Libraries Government Documents Department

Sensitivity of the deuteron form factor to nucleon resonances

Description: The sensitivity of the deuteron form factor to contributions from the excited states of the nucleon is explored using a simple model of the nucleon-nucleon interaction which employs a tower of charged nucleon resonances. The model is manifestly covariant, analytically solvable, and gauge invariant. The consequences of this model are studied in the simplest possible framework. The authors assume that all particles have spin zero and that the tower has only three charged members, which consist of the proton, the Roper, and a higher state in the vicinity of the D{sub 13}. Nucleon-nucleon S-wave phase shifts and the deuteron form factor are calculated using this three member tower, and the results are compared to similar calculations using the proton ground state only. They conclude that the deuteron form factor is insensitive to the presence of excited states of the proton unless those states are of sufficiently low mass to produce strong inelasticities in NN scattering channels.
Date: October 1, 1997
Creator: Herbst, Kelly Ann & Gross, Franz
Partner: UNT Libraries Government Documents Department

Interactions, Currents and the Structure of Few-Nucleon Systems

Description: The current understanding of the structure of nuclei with up to A=8, including energy spectra, electromagnetic form factors, and weak transitions, is reviewed within the context of a realistic approach to nuclear dynamics based on two- and three-nucleon interactions and associated electro-weak currents. Low-energy radiative and weak capture reactions of astrophysical relevance involving these light systems are also discussed.
Date: October 1, 2000
Creator: Schiavilla, R.
Partner: UNT Libraries Government Documents Department

A search for the production of Direct Leptons in nucleon-nucleus and nucleus-nucleus collisions. Progress report, April 1, 1991--December 1, 1993

Description: The purpose of this report is to describe activities performed by the Intermediate Energy Nuclear Physics Group (IENPG) at the Louisiana State University (LSU) under the terms of grant FG05-88ER40445. The report will cover, for the most part, the period of time between April 1, 1991, and the present. The principal focus of our activities is currently the muon subgroup of the PHENIX Collaboration. We are, however, in the process of concluding other activities, specifically our memberships in the Di-Lepton Spectrometer (DLS) Collaboration at LBL and the AMY Collaboration at KEK. These activities have been thoroughly discussed in previous progress reports and renewal proposals, and further discussion of these activities is possibly repetitious. However, this report has been prepared under the assumption that none of the referees with the exception of the grant monitor is familiar with the group or its previous work. Consequently we shall cite a few examples of our contributions to these collaborations when there seem to be valid reasons for so doing.
Date: December 15, 1993
Creator: Kirk, P. N.
Partner: UNT Libraries Government Documents Department

Chiral invariant phase space event generator

Description: The CHIPS model and its first implementation within the GEANT4 simulation software package are considered. Hadron production in the process of nucleon-antinucleon annihilation is used as the basic example showing the structure of the model and corresponding software modeling algorithms. Model calculations of multiplicities and spectra of secondary hadrons in the annihilation process are compared with experimental data.
Date: February 1, 2000
Creator: Degtyarenko, P.V.; Kossov, M.V. & Wellisch, H.P.
Partner: UNT Libraries Government Documents Department

A Dependence Study of $\Xi^{*0}$ and $\bar{\Xi}^{*0}$ in 250 GeV/c $\pi^-$. $K^-$ -nucleon Interactions

Description: A direct measurement of the mass number (A) dependence of the production of the hyperon {Xi}*{sup 0} and its opposite {bar {Xi}}*{sup 0} in {pi}{sup -}, K{sup -} beam-nucleon interactions at 250 GeV/c is reported. The data derive from the experiment E769 at Fermilab. The results were obtained for different targets: Be, Al, Cu and W. It was observed the data are found to be well described by the parametrization {sigma}{sub A} = {sigma}{sub 0}A{sup {alpha}}, {alpha} being calculated for different beams. The results obtained are compared with those results of E769 experiment. The results shown here are preliminary.
Date: April 1, 2005
Creator: Seixas de Rezende, Fabio Antonio & /Rio de Janeiro, CBPF
Partner: UNT Libraries Government Documents Department