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in creator/contributor: "Wiringa, R.B."

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Variational Monte Carlo calculations of few-body nuclei

The variational Monte Carlo method is described. Results for the binding energies, density distributions, momentum distributions, and static longitudinal structure functions of the /sup 3/H, /sup 3/He, and /sup 4/He ground states, and for the energies of the low-lying scattering states in /sup 4/He are presented. 25 refs., 3 figs.

Date: January 1, 1986

Creator: Wiringa, R. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Relativistic effects in the binding energies of few-body nuclei

We have examined the consequences of Poincare invariance for the binding-energy calculations of few-body nuclei. Nonrelativistic Hamiltonians have been considered in an attempt to fit simultaneously the binding energies of 2-, 3-, 4-body nuclei and that of nuclear matter. Even with reasonable three-body forces it appears to be difficult to simultaneously fit the binding energies of 3- and 4-body nuclei. The size of the discrepancy is of the order of possible relativistic effects. After eliminat… more

Date: January 1, 1983

Creator: Coester, F. & Wiringa, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Microscopic calculations of nuclear structure and nuclear correlations

A major goal in nuclear physics is to understand how nuclear structure comes about from the underlying interactions between nucleons. This requires modelling nuclei as collections of strongly interacting particles. Using realistic nucleon-nucleon potentials, supplemented with consistent three-nucleon potentials and two-body electroweak current operators, variational Monte Carlo methods are used to calculate nuclear ground-state properties, such as the binding energy, electromagnetic form factor… more

Date: January 1, 1992

Creator: Wiringa, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Monte Carlo calculations of few-body and light nuclei

Date: January 1, 1992

Creator: Wiringa, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Microscopic calculations of nuclear structure and nuclear correlations

Date: July 1, 1992

Creator: Wiringa, R. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quantum Monte Carlo calculations for light nuclei.

Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 40 different (J{pi}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that directly produc… more

Date: October 23, 1998

Creator: Wiringa, R. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Monte Carlo calculations of few-body and light nuclei

Date: February 1, 1992

Creator: Wiringa, R. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quantum Monte Carlo calculations for light nuclei

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… more

Date: October 1, 1997

Creator: Wiringa, R.B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Nucleon-nucleon interactions

Nucleon-nucleon interactions are at the heart of nuclear physics, bridging the gap between QCD and the effective interactions appropriate for the shell model. We discuss the current status of {ital NN} data sets, partial-wave analyses, and some of the issues that go into the construction of potential models. Our remarks are illustrated by reference to the Argonne {ital v}{sub 18} potential, one of a number of new potentials that fit elastic nucleon-nucleon data up to 350 MeV with a {Chi}{sup 2}… more

Date: December 31, 1996

Creator: Wiringa, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Quantum Monte Carlo Calculations for Light Nuclei

Quantum Monte Carlo calculations of ground and low-lying excited states for nuclei with A {le} 8 are made using a realistic Hamiltonian that fits NN scattering data. Results for more than 30 different (j{sup {prime}}, T) states, plus isobaric analogs, are obtained and the known excitation spectra are reproduced reasonably well. Various density and momentum distributions and electromagnetic form factors and moments have also been computed. These are the first microscopic calculations that direct… more

Date: August 1, 1998

Creator: Wiringa, R. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Monte Carlo approaches to the few-nucleon continuum

Variational and Green`s Function Monte Carlo methods are reviewed as applied to the study of the few-nucleon continuum at low- and intermediate-energies. Results recently obtained for the radiative and weak capture reactions n + {sup 3}He {yields} {sup 4}He + {gamma} and p + {sup 3}He {yields} {sup 4}He + e{sup +} + {nu}{sub e}, the {sup 5}He P-wave resonances, and the inclusive and exclusive electron scattering reactions on {sup 3}H and the helium isotopes are summarized.

Date: August 1, 1994

Creator: Schiavilla, R.; Carlson, J. & Wiringa, R. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Weak Transitions in A=6 and 7 Nuclei

The {sup 6}He beta decay and {sup 7}Be electron capture processes are studied using variational Monte Carlo wave functions, derived from a realistic Hamiltonian consisting of the Argonne upsilon{sub 18} two-nucleon and Urbana-IX three-nucleon interactions. The model for the nuclear weak axial current includes one- and two-body operators with the strength of the leading two-body term - associated with Delta-isobar excitation of the nucleon -- adjusted to reproduce the Gamow-Teller matrix element… more

Date: January 1, 2001

Creator: Schiavilla, R. & Wiringa, R.B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Proceedings of a Symposium on the Occasion of the 40th Anniversary of the Nuclear Shell Model

This report contains papers on the following topics: excitation of 1p-1h stretched states with the (p,n) reaction as a test of shell-model calculations; on Z=64 shell closure and some high spin states of {sup 149}Gd and {sup 159}Ho; saturating interactions in {sup 4}He with density dependence; are short-range correlations visible in very large-basis shell-model calculations ; recent and future applications of the shell model in the continuum; shell model truncation schemes for rotational nuclei… more

Date: March 1, 1990

Creator: Lee, T. S. H. & Wiringa, R. B.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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A six-body calculation of the alpha-deuteron radiative capture cross section

The authors have computed the cross section for the process d + alpha -> {sup 6}Li + gamma at the low energies relevant for primordial nucleosynthesis and comparison with laboratory data. The final state is a six-body wave function generated by the variational Monte Carlo method from the Argonne v-18 and Urbana IX potentials, including improved treatment of large-particle-separation behavior. The initial state is built up from the alpha-particle and deuteron ground-state solutions for these … more

Date: September 1, 2000

Creator: Nollett, K. M.; Wiringa, R. B. & Schiavilla, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Charge-independence-breaking in the triton

We find the effect of the observed charge-independence-breaking in {sup 1}S{sub 0} nucleon-nucleon scattering on the binding energy of the triton to be of order 80 keV. When corrections for this effect are made in an 18-channel momentum-space Faddeev calculation, we find the Paris and Argonne v{sub 14} potentials triton binding energies that differ by only 20 keV.

Date: January 1, 1990

Creator: Gloeckle, W.; Lee, T. S. H. & Wiringa, R. B.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

An accurate nucleon-nucleon potential with charge-independence breaking

The authors present a new high-quality nucleon-nucleon potential with explicit charge dependence and charge asymmetry, which they designate Argonne {upsilon}{sub 18}. The model has a charge-independent part with fourteen operator components that is an updated version of the Argonne {upsilon}{sub 14} potential. Three additional charge-dependent and one charge-asymmetric operators are added, along with a complete electromagnetic interaction. The potential has been fit directly to the Nijmegen pp … more

Date: August 1, 1994

Creator: Wiringa, R. B.; Stoks, V. G. J. & Schiavilla, R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Femtometer toroidal structures in nuclei

The two-nucleon density distributions in states with isospin T=0, spin S=1 and projection M{sub S}=0 and {+-}1 are studied in {sup 2}H, {sup 3,4}He, {sup 6,7}Li and {sup 16}O. The equidensity surfaces for M{sub S}=0 distributions are found to be toroidal in shape, while those of M{sub S}={+-}1 have dumbbell shapes at large density. The dumbbell shapes are generated by rotating tori. The toroidal shapes indicate that the tensor correlations have near maximal strength at r < 2 fm in all these … more

Date: March 1, 1996

Creator: Forest, J.; Pandharipande, V.; Pieper, S.; Wiringa, R.B.; Shiavilla, R. & Arriaga, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Variational theory of nuclear and neutron matter

In these lectures we will discuss attempts to solve the A = 3 to {infinity} nuclear many-body problems with the variational method. We choose the form of a variational wave function {Chi}{sub v}(1, 2{hor ellipsis}A) to describe the ground state. The {Chi}{sub v} and the ground-state energy E{sub v} are obtained by minimizing E{sub v} = {l angle}{Chi}{sub v}{vert bar}H{vert bar}{Chi}{sub v}{r angle}/{l angle}{Chi}{sub v}{vert bar}{Chi}{sub v}{r angle} with respect to variations in {Chi}{sub v}. … more

Date: June 1, 1989

Creator: Pandharipande, V.R.; Wiringa, R.B. (Illinois Univ., Urbana, IL (USA). Dept. of Physics & Argonne National Lab., IL (USA))

Item Type: Article

Partner: UNT Libraries Government Documents Department