Showing papers on "Nuclear matter published in 1972"
TL;DR: In this article, Hartree-Fock equations for spherical nuclei using Skyrme's density-dependent effective nucleon-nucleon interaction are discussed systematically and the general formula for the mean energy of a spherical nucleus derived.
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.
1,340 citations
TL;DR: In this paper, an expansion for the nuclear wave-function density matrix in relative and cm coordinates is developed such that the leading term is the corresponding nuclear-matter density matrix at the local neutron and proton density truncation.
Abstract: An expansion for the nuclear wave-function density matrix in relative and cm coordinates is developed such that the leading term is the corresponding nuclear-matter density matrix at the local neutron and proton density Truncation of all derivatives beyond second order yields an extremely simple form for the energy density which retains all the computational simplicity of the modified $\ensuremath{\delta}$ interaction and the Skyrme force, while maintaining contact with nuclear-matter theory based on a realistic interaction and reproducing the results of more-complicated density-dependent Hartree-Fock calculations
396 citations
374 citations
TL;DR: In this paper, the authors studied the optical-model potential for nucleon-nucleus scattering within the framework of the Green function approach to the many-body problem and showed that the same convergence parameter appears in both expansions, and the one-and two-hole line contributions are studied in detail, numerical estimates are provided and compared with experiment.
127 citations
TL;DR: In this paper, a momentum-space method is developed for the calculation of three-body terms in the Brueckner-Bethe method for nuclear matter, which is similar to one used earlier for central $S$-wave potentials.
Abstract: A momentum-space method is developed for the calculation of three-body terms in the Brueckner-Bethe method for nuclear matter. The method is similar to one used earlier for central $S$-wave potentials. Here we extend it to the full nuclear force, including tensor forces, spin-orbit forces, etc. Furthermore, we show how the method can be used to investigate the possibility of long-range correlations in nuclear matter by summing the generalized ring series. The numerical accuracy obtainable with various mesh parameters and cut-offs in momentum space, and with various truncations of partial-wave expansions, is thoroughly explored. Several angle-average approximations are used, and the estimated numerical accuracy in the three-body cluster energy is 10-15%. The method is applied to a central potential ${v}_{2}$, a semirealistic potential ${v}_{6}$ (Reid), which has a tensor force, and to the Reid potential, augmented by an interaction that is consistent with empirical scattering phase shifts in two-body partial waves with $j\ensuremath{\ge}3$. In all cases the three-body contribution to the energy is correctly given in order of magnitude by ${\ensuremath{\kappa}}_{2}{D}_{2}$, where ${D}_{2}$ is the two-body contribution and ${\ensuremath{\kappa}}_{2}$ is the usual convergence parameter of the Brueckner-Bethe method. The generalized ring series is found to converge rapidly, indicating that long-range correlations are not very important for the binding energy of nuclear matter. The Reid potential is found to saturate at the right energy but at too high a density.NUCLEAR STRUCTURE Method for solving Brueckner-Bethe three-body equations in nuclear matter developed and applied to the Reid potential.
119 citations
79 citations
TL;DR: In this article, a microscopic investigation of isotropic proton superfluidity in neutron-star matter, in the framework of the method of correlated basis functions, is presented, in which 1S0 proton pairing is found to be considerably weaker than 1S 0 neutron pairing, as measured by the peak value of the gap ΔkFN at the Fermi surface with respect to the fermi wave number kFN of the nucleon component in question.
67 citations
TL;DR: In this article, Hartree-Fock wavefunctions for 57 light nuclei in the region 4⩽ A ⩽ 41, N − Z = 0, ± 1, and the Coulomb two-body interaction No. 2 of Saunier and Pearson is used and seen to be a reasonable energy and density independent approximation to the required reaction matrix.
49 citations
TL;DR: In this paper, the authors investigated the structure and composition of neutron star matter in the density region 3.1 × 10 11 −2 × 10 15 g/cm 3 and showed that very small modifications in the details of the nuclear matter energy may lead to considerable differences in the resulting neutron star structure; for example the density of matter at the solid-to-liquid phase boundary is very sensitive to such details.
44 citations
TL;DR: In this paper, it was shown that in Jastrow theory, a treatment of three-hole-orbital contributions in harmony with the usual practice of Brueckner-Bethe-Goldstone theory can be quite unwise for sizeable values of the wound parameter.
43 citations
TL;DR: In this paper, the tensor force in nuclear matter is treated using the lowest-order variational method with short-range correlations restricted to nearest neighbours, and the nuclear matter results from k F = 0.7 to 1.8 fm −1 are in very close agreement with those of the Brueckner-Bethe calculations.
TL;DR: In this paper, it was shown that the inelastic process in which two nucleons scatter into a nucleon and a Δ (1236 MeV) can, in second order, contribute about 34 MeV/A attraction to the binding energy of nuclear matter.
TL;DR: In this article, the paramagnetic susceptibility of dense neutron matter was calculated for the Reid soft core potential with the lowest order variational method, and no transition to ferromagnetic state was predicted for k F −1.
TL;DR: In this article, the absolute value of reaction cross sections, as given by the pre-equilibrium exciton model, was estimated using Fermi gas approximation, and a general agreement with experimental data, particularly in the gross $A$ dependence was obtained.
Abstract: The absolute value of ($n,p$) reaction cross sections, as given by the pre-equilibrium exciton model is estimated using Fermi gas approximation.A general agreement with experimental data, particularly in the gross $A$ dependence is obtained. The energy range considered is 10-20 MeV, and the nuclei are those with $Ag100$: In these ranges evaporation is negligible and the analysis is rather easy. The approximate life-time of one single-particle exciton in nuclear matter is also deduced.
TL;DR: In this article, an analysis was made of proton scattering from the ground and the first 2+ state of the stable even isotopes of samarium at 50.8 MeV.
TL;DR: The spin and isospin dependent parts of the single-particle potential in nuclear matter are calculated at the Fermi surface with the Brueckner-Gammel-Thaler and the Reid soft core potential as discussed by the authors.
TL;DR: In this article, the saturation properties in nuclear matter of six realistic nucleon-nucleon potentials are examined from the viewpoint of the hole-line expansion of Bethe and Brandow.
TL;DR: The infinite-nuclear-matter properties of our momentum space OBEP have been calculated using the angle-averaged Pauli operator, and the effective mass approximation for the hole spectrum to be determined self-consistently and a free-particle spectrum has been determined as mentioned in this paper.
TL;DR: In this article, the effect of the density dependence of the effective forces on spherical nuclear calculations is examined and the results have been compared with experiments with different long-range density dependence.
TL;DR: In this article, an approximate treatment of Coulomb forces in the nuclear three-body problem is proposed which is based on the assumption that three body dynamics are dominated by the nuclear interactions, and approximate threeparticle integral equations are derived which incorporate Coulomb effects and have structure identical to the Alt-Grassberger-Sandhas equations.
TL;DR: In this paper, the density dependent characteristic reduction parameters derived from a realistic twonucleon interaction were used to estimate the solidification pressure of neutron matter in terms of the quantum mechanical principle of corresponding states.
Abstract: Solidification pressure PS of neutron matter has been estimated on the basis of the quantum mechanical principle of corresponding states, using density dependent characteristic reduction parameters derived from a realistic twonucleon interaction. Three procedures yield Ps¯≈ 5 × 1027 atm, in essential agreement with an earlier estimate1.
TL;DR: The noncentral components of the Sprung-Banerjee effective interaction were derived from a nuclear matter calculation based on the Reid potential as discussed by the authors, and the strength of the spin-orbit force was about 10% smaller than empirical values used in recent Hartree-Fock calculations using density-dependent interactions.
TL;DR: The macroscopic approach to fission and fusion physics is formulated in this article, where a minimum set of three degrees of freedom is described qualitatively and gross features of the potential energy in this configuration space are discussed.
Abstract: The macroscopic approach to fission and fusion physics is formulated. A minimum set of three degrees of freedom is described qualitatively .. The gross features of the potential energy in this configuration space are discussed. The problem of nuclear viscosity is mentioned and comparisons with liquid He3 are made. Some effects of large angular momenta are described.
TL;DR: In this article, the question of superfluidity in neutron matter was investigated in the framework of BCS-Bogoljubov-Theory, and the gap-equation for a semirealistic hard core and a soft-core potential was developed.
Abstract: The question of superfluidity in neutron matter is investigated in the framework of BCS-Bogoljubov-Theory. Solving the gap-equation for a semirealistic hard-core and a soft-core potential, a rapidly converging numerical method is developed. The results are applied to neutron star models.
TL;DR: In this article, the optical model derived from Watson's multiple scattering theory is applied to the analysis of the π 12 C elastic scattering around the ( 3 2, 3 2 ) resonance.
TL;DR: In this paper, the Glauber theory for diffraction dissociation of hadrons from heavy nuclei is modified to take into account the fact that the dissociated system D can oscillate between many internal states as it propagates through nuclear matter.
TL;DR: In this paper, the influence of nuclear forces on Coulomb fission cross sections is studied in a classical dynamical model and within the quantum-mechanical methods of Coulomb excitation.
TL;DR: In this paper, the authors investigated the transport properties of neutron star matter in the framework of the Landau theory and found that zero sound cannot propagate in neutron star material because of very strong Landau damping.
Abstract: In the framework of the Landau theory transport properties of neutron matter are investigated. An important problem is the propagation of first and zero sound and their damping. It is found that zero sound cannot propagate in neutron star matter because of very strong Landau damping. On the other hand first sound is comparatively weakly damped. The absorption coefficient is small and depends sensitively—just as the viscosity and the relaxation time of quasi-particles—on the temperature.