Physical Review C 

About: Physical Review C is an academic journal published by American Physical Society. The journal publishes majorly in the area(s): Nucleon & Neutron. It has an ISSN identifier of 2469-9985. Over the lifetime, 42003 publications have been published receiving 869753 citations. The journal is also known as: PRC.

Precision Measurement of Half-Lives and Specific Activities of U 235 and U 238

Abstract: New determinations of the half-lives of $^{235}\mathrm{U}$ and $^{238}\mathrm{U}$ have been made Improved techniques have allowed the half-life values to be measured with greater accuracy than has been heretofore achieved Samples were prepared by molecular plating and counted in a intermediate-geometry $\ensuremath{\alpha}$-proportional counter with an extremely flat pulse-height plateau The small amount of residual nonplated uranium was counted in a $2\ensuremath{\pi}$ counter Energy analysis with a silicon-junction detector was used to measure the presence of "foreign" activities For $^{235}\mathrm{U}$, the measured specific activity was (47981\ifmmode\pm\else\textpm\fi{}33) (dis/min)/(mg $^{235}\mathrm{U}$), corresponding to a half-life of (70381\ifmmode\pm\else\textpm\fi{}00048) \ifmmode\times\else\texttimes\fi{} ${10}^{8}$ yr For $^{238}\mathrm{U}$, the specific activity was measured as (74619\ifmmode\pm\else\textpm\fi{}041) (dis/min)/(mg $^{238}\mathrm{U}$), corresponding to a half-life of (44683\ifmmode\pm\else\textpm\fi{}00024) \ifmmode\times\else\texttimes\fi{} ${10}^{9}$ yr Errors quoted are statistical (standard error of the mean), based upon the observed scatter of the data This scatter exceeds that expected from counting statistics alone We believe that systematic errors, if present, will no more than double the quoted errors

Accurate nucleon-nucleon potential with charge-independence breaking

Abstract: 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 and np scattering data base, low-energy nn scattering parameters, and deuteron binding energy. With 40 adjustable parameters it gives a {chi}{sup 2} per datum of 1.09 for 4,301 pp and np data in the range 0--350 MeV.

Equation of state of nucleon matter and neutron star structure

Abstract: Properties of dense nucleon matter and the structure of neutron stars are studied using variational chain summation methods and the new Argonne ${v}_{18}$ two-nucleon interaction, which provides an excellent fit to all of the nucleon-nucleon scattering data in the Nijmegen database. The neutron star gravitational mass limit obtained with this interaction is 1.67${M}_{\ensuremath{\bigodot}}.$ Boost corrections to the two-nucleon interaction, which give the leading relativistic effect of order ${(v/c)}^{2},$ as well as three-nucleon interactions, are also included in the nuclear Hamiltonian. Their successive addition increases the mass limit to 1.80 and 2.20 ${M}_{\ensuremath{\bigodot}}.$ Hamiltonians including a three-nucleon interaction predict a transition in neutron star matter to a phase with neutral pion condensation at a baryon number density of $\ensuremath{\sim}0.2 {\mathrm{fm}}^{\ensuremath{-}3}.$ Neutron stars predicted by these Hamiltonians have a layer with a thickness on the order of tens of meters, over which the density changes rapidly from that of the normal to the condensed phase. The material in this thin layer is a mixture of the two phases. We also investigate the possibility of dense nucleon matter having an admixture of quark matter, described using the bag model equation of state. Neutron stars of 1.4${M}_{\ensuremath{\bigodot}}$ do not appear to have quark matter admixtures in their cores. However, the heaviest stars are predicted to have cores consisting of a quark and nucleon matter mixture. These admixtures reduce the maximum mass of neutron stars from 2.20 to 2.02 (1.91) ${M}_{\ensuremath{\bigodot}}$ for bag constant $B=200 (122) {\mathrm{M}\mathrm{e}\mathrm{V}/\mathrm{f}\mathrm{m}}^{3}.$ Stars with pure quark matter in their cores are found to be unstable. We also consider the possibility that matter is maximally incompressible above an assumed density, and show that realistic models of nuclear forces limit the maximum mass of neutron stars to be below 2.5${M}_{\ensuremath{\bigodot}}.$ The effects of the phase transitions on the composition of neutron star matter and its adiabatic index $\ensuremath{\Gamma}$ are discussed.

The High precision, charge dependent Bonn nucleon-nucleon potential (CD-Bonn)

Abstract: We present a charge-dependent one-boson-exchange nucleon-nucleon $(\mathrm{NN})$ potential that fits the world proton-proton data below 350 MeV available in the year 2000 with a ${\ensuremath{\chi}}^{2}$ per datum of 1.01 for 2932 data and the corresponding neutron-proton data with ${\ensuremath{\chi}}^{2}/\mathrm{datum}$ $=1.02$ for 3058 data. This reproduction of the $\mathrm{NN}$ data is more accurate than by any phase-shift analysis and any other $\mathrm{NN}$ potential. This is achieved by the introduction of two effective $\ensuremath{\sigma}$ mesons the parameters of which are partial-wave dependent. The charge dependence of the present potential (which we call ``CD-Bonn'') is based upon the predictions by the Bonn full model for charge symmetry and charge-independence breaking in all partial waves with $Jl~4.$ The potential is represented in terms of the covariant Feynman amplitudes for one-boson exchange which are nonlocal. Therefore, the off-shell behavior of the CD-Bonn potential differs in a characteristic way from commonly used local potentials and leads to larger binding energies in nuclear few- and many-body systems, where underbinding is a persistent problem.

Hartree-Fock Calculations with Skyrme's Interaction. I. Spherical Nuclei

Abstract: Hartree-Fock calculations for spherical nuclei using Skyrme's density-dependent effective nucleon-nucleon interaction are discussed systematically. Skyrme's interaction is described and the general formula for the mean energy of a spherical nucleus derived. Hartree-Fock equations are obtained by varying the mean energy with respect to the single-particle wave functions of occupied states. Relations between the parameters of the Skyrme force and various general properties of nuclear matter and finite nuclei are analyzed. Calculations have been made for closed-shell nuclei using two rather different sets of parameters, both of which give good binding energies and radii for $^{16}\mathrm{O}$ and $^{208}\mathrm{Pb}$. Both interactions give good binding energies and charge radii for all closed-shell nuclei. Calculated electron scattering angular distributions agree qualitatively with experiment, and for one interaction there is good quantitative agreement. The single-particle energies calculated with the two interactions are somewhat different owing to a different nonlocality of the Hartree-Fock potentials, but both interactions give the correct order and density of single-particle levels near the Fermi level. They differ most strongly in their predictions for the energies of $1s$ single-particle states.