Showing papers on "Nuclear matter published in 1980"
TL;DR: In this article, a self-consistent approach allowing the introduction of pairing into a comprehensive study of the bulk as well as the structure properties of nuclei is presented, which allows the extraction of the mean field and the pairing field in the framework of the Bogolyubov theory.
Abstract: A self-consistent approach allowing the introduction of pairing into a comprehensive study of the bulk as well as the structure properties of nuclei is presented. It is emphasized that the density-dependent effective force used in the calculations reported here does permit the extraction of the mean field and the pairing field in the framework of the Bogolyubov theory. First, a brief review of Hartree-Fock-Bogolyubov formalism with density-dependent interactions is presented. Then the derivation of the effective interaction is explained and some details concerning the nuclear matter properties are given. Finally, we report the studies on spherical nuclei with special reference to the pairing properties. In order to demonstrate the versatility of our approach a comprehensive study of various nuclear properties is given. In view of the abundance of results obtained with our approach we plan to report the results on the deformed nuclei in a future publication.NUCLEAR STRUCTURE Density-dependent Hartree-Fock-Bogolyubov (DDHFB) approximation applied to the calculations of the structure of spherical nuclei: binding energies, pairing correlations, density distributions, magnetic form factors, and quasiparticle spectra.
842 citations
TL;DR: In this article, the influence of coherent forward scattering in matter upon neutrino oscillations in the three-neutrino picture is evaluated and illustrated using an oscillation solution suggested by solar and reactor data.
Abstract: We evaluate the influence of coherent forward scattering in matter upon neutrino oscillations in the three-neutrino picture. We write down the exact solution and also approximate first-order solutions that exhibit general features more transparently. Oscillation characteristics in matter that could be observed in deep-mine experiments are discussed and illustrated using an oscillation solution suggested by solar and reactor data.
317 citations
CERN1
TL;DR: In this paper, the authors developed a statistical bootstrap model of strong interactions for hadronic matter with particular emphasis on hot nuclear matter as created in relativistic heavy ion collisions and applied their theory to calculate temperatures and average transverse momenta of nucleons and pions from the decay of hadronic fireballs.
254 citations
TL;DR: In this paper, the Fourier transform of the response function with respect to the energy transfer to the nucleus is studied in terms of the "characteristic function" F ( t ), and the dependence of these observables on ground state properties and the final state interaction between ejected nucleon and residual nucleus is calculated for a variety of models.
118 citations
TL;DR: In this article, an energy-dependent local potential for heavy-ion (HI) scattering is derived from Reid's softcore interaction using the Brueckner theory, and the optical potential for HI scattering is evaluated using the energy-density formalism.
77 citations
CERN1
TL;DR: In this paper, the annihilation of antiprotons at LEAR momenta of 0.5 − 1.5 GeV/c on heavy nuclei is proposed, and a qualitative discussion of possible interesting reaction channels is presented.
73 citations
TL;DR: The pion brems-strahlung, a chunk of nuclear matter, is decelerated along a straight path, the deceleration being parametrized by the "stopping time" τ as mentioned in this paper.
Abstract: The production of pions in relativistic heavy ion collisions may be regarded as classical radiation process. The source of this "pion brems-strahlung", a chunk of nuclear matter, is decelerated along a straight path, the deceleration being parametrized by the "stopping time" τ. The collective character of the source causes measureable pion production cross-sections even below the single nucleon threshold energy. The emitted pions appear as a strongly forward peaked beam with high kinetic energy.
53 citations
TL;DR: In this paper, phase diagrams for bulk nuclear matter at finite temperatures and variable proton concentrations are presented and discussed, showing that a binary system exhibits a line of critical points, line of equal concentrations, and a line-of-maximum temperatures.
Abstract: Phase diagrams for bulk nuclear matter at finite temperatures and variable proton concentrations are presented and discussed. This binary system exhibits a line of critical points, a line of equal concentrations, and a line of maximum temperatures. The phenomenon of retrograde condensation is also possible.
51 citations
CERN1
TL;DR: In this article, the temperature dependence of a conjectured first-order phase transition between nuclear matter and quark-gluon matter is calculated for temperatures below T = 200 MeV.
50 citations
TL;DR: In this paper, strong density dependence in the two-nucleon effective interaction was shown in inelastic (p,p') differential cross section and polarization data for E/sub p/approx.150 MeV.
Abstract: Definitive evidence for strong density dependence in the two-nucleon effective interaction is noted in inelastic (p,p') differential cross section and polarization data for E/sub p/approx.150 MeV. These effects are quite sensitive to variations in the nuclear medium and are well described, for inelastic scattering, by the local density approximation with use of density-dependent effective interactions from nuclear matter.
48 citations
TL;DR: In this article, the influence of the nuclear equation of state and the phase transition from nuclear to quark matter in HEHI collisions is discussed. And the authors develop the essential theoretical tools for the treatment of the dynamics of HEI collisions.
Journal Article•
TL;DR: In this paper, it was shown that the cooling of neutron matter may be accompanied by a phase transition from one anisotropic superfluid state to another with very different physical properties.
Abstract: It is shown that the cooling of neutron matter may be accompanied by a phase transition from one anisotropic superfluid state to another with very different physical properties. Such phase transitions must have a significant influence on the evolution of neutron stars.
TL;DR: In this article, spherical hydrodynamical expansion and linear compression and expansion are calculated in viscous relativistic hydrogynamics, and the break-up process subsequent to the hydroynamical collective flow is also taken into account.
Abstract: Spherical hydrodynamical expansion and linear compression and expansion are calculated in viscous relativistic hydrodynamics. The break-up process subsequent to the hydrodynamical collective flow is also taken into account. The results lay the foundation of the blast-wave model and the comparison of the linear and spherical models with the experiment provides further evidence for the soft nuclear matter equation of state.
TL;DR: In this paper, a model is employed to describe the velocity dependence of the effective nucleon-nucleon interaction in nuclear matter, where the interactions in this model consist of π− and ρ-meson exchange, together with short-range correlations induced by the strongly repulsive potential resulting from ω-meanson exchange.
TL;DR: In this article, the average nucleon-nucleus potential at low and medium energy is investigated in the framework of a relativistic quantum field model using the same input parameters as Brockmann in his recent study of nuclear ground states.
Abstract: The average nucleon-nucleus potential at low and medium energy is investigated in the framework of a relativistic quantum field model Using the same input parameters as Brockmann in his recent study of nuclear ground states, we calculate the self-consistent relativistic Hartree potential at positive energy in the case of infinite nuclear matter and of $^{16}\mathrm{O}$ and $^{40}\mathrm{Ca}$ This potential is the sum of a scalar operator and of the fourth component of a vector operator We construct its Schr\"odinger-equivalent potential by eliminating the small component of the Dirac spinor The central part of this Schr\"odinger-equivalent potential is in fair agreement with empirical values at low and intermediate energy Particular attention is paid to the intermediate energy domain, in which the calculated potential is repulsive in the nuclear interior and attractive at the nuclear surface This is in keeping with some empirical evidence and is similar to results found in the framework of the nonrelativistic Brueckner-Hartree-Fock approximation The spin-orbit potential of the relativistic Hartree model is also in good agreement with empirical valuesNUCLEAR REACTIONS Calculated average nuclear field of nuclear matter, $^{16}\mathrm{O}$ and $^{40}\mathrm{Ca}$ at positive energy from relativistic Hartree approximation
TL;DR: In this paper, the dependence of pion bremsstrahlung on the deceleration of the nuclei in relativistic heavy ion collisions was investigated, which can be used to search for abnormal nuclear states experimentally.
TL;DR: In this article, it was pointed out that recently predicted neutron-antineutron oscillations lead to an annihilation rate in nuclei which should be detectable with present experiments, and that such an event can be detected with a present experiment.
Abstract: Points out that recently predicted neutron-antineutron oscillations lead to an annihilation rate in nuclei which should be detectable with present experiments.
TL;DR: In this paper, Hartree-Fock calculations on asymmetric semi-infinite nuclear matter have been performed with a family of finite-range Gogny-type forces, and the computed values of the droplet-model symmetry coefficients J, L, M and Q are in good agreement with recent mass-formula fits.
TL;DR: In this article, the authors discuss a possible percolation of hot, dense hadronic and quark matter in violent high-energy heavy ion collisions, where the quark is treated in the bag model as an excited state of nuclear matter.
TL;DR: In this paper, a new relativistic theory of nuclear matter which allows for negative energy components in the nucleon wave function introduces a major modification in the saturation curve for nuclear matter.
Abstract: Calculations made with use of a new relativistic theory of nuclear matter which allows for negative-energy components in the nucleon wave function introduce a major modification in the saturation curve for nuclear matter. For example, a boson-exchange potential which saturates at over twice the empirical density and yields a binding energy of about 23 MeV particle is brought into general agreement with the empirical data when relativistic effects are included. This analysis indicates that nuclear matter should be treated as a relativistic system.
TL;DR: In this article, a modification of the formula suitable for proton or neutron energies from 0 to 10 MeV was proposed, which is suitable for low-energy scattering, but it is not suitable for high energy scattering.
Abstract: In a previous article, we gave a parametrization of a theoretical microscopic optical model potential for nucleon energies ranging from 10 to 160 MeV. However, it is not suitable for low-energy scattering. Reanalyzing our nuclear matter results, we propose a modification of the formula suitable for proton or neutron energies from 0 to 10 MeV.
TL;DR: In this article, the formation of abnormal super-dense nuclear matter (density isomers) is investigated in a schematic model for the nuclear equation of state in high energy heavy ion collisions above a critical bombarding energy and below a critical impact parameter.
Abstract: We study heavy ion collisions at bombarding energiesE
LAB/n∼ 20–200 MeV within the three-dimensional NFD- and TDHF-models. A surprisingly good agreement between the results of the different models is found: The comparison phenomena occuring at these bombarding energies are quantitatively similar as a function of the bombarding energy as well as for various impact parameters. The formation of abnormal superdense nuclear matter (“density isomers”) is investigated in a schematic model for the nuclear equation of state. Again we find very similar results in the two models. Density isomers can be formed in high energy heavy ion collisions above a critical bombarding energy and below a critical impact parameter, which both depend on the details of the nuclear equation of state. Cross sections for the formation of density isomers are presented. An experiment for the detection of abnormal nuclear matter in fast, central heavy ion collisions is proposed.
TL;DR: In this paper, the π ϱ -and 2 ϱ exchange three-nucleon forces mediated by the Δ(1232 MeV) resonance were derived, in the static approximation, and the contributions, in nuclear matter, from πϱ and 2π ϱ potentials were found to reduce the attraction of the formerly considered 2 π -exchange three nucleon force.
TL;DR: In this article, a modification of the phenomenological Skyrme interaction is proposed to obtain a nuclear equation of state fitted to the binding energy, saturation density, and incompressibility of nuclear matter and which remains causal at higher densities.
Abstract: We propose a modification of the phenomenological Skyrme interaction in order to obtain a nuclear equation of state fitted to the binding energy, saturation density, and incompressibility of nuclear matter and which remains causal at higher densities. The properties of this and other equations of state at transnuclear densities are compared and the implications for stellar collapse and cold neutron structure are briefly discussed.
01 Jan 1980
TL;DR: In this article, the authors studied the properties of nuclear matter within the framework of a modified and generalized statistical bootstrap model in which the volume of a fireball grows with its mass.
Abstract: We study the properties of nuclear matter within the framework of a modified and generalized statistical bootstrap model in which the volume of a fireball grows with its mass. We find that the such described nuclear matter can exist in two phases. In particular we consider in a numerical example the high temperature (T ≲ T0 ≈ 150 MeV) regime of the gaseous phase with a density of less than ~ 0.75 of normal nuclear density.
TL;DR: In the general framework of the fireball model, the authors analyzes the observed momentum spectra of protons and light nuclei produced in high-energy particle-nucleus and nucleus nucleus collisions and demonstrates that the data including the well-known phenomena of cumulative effect can be naturally accounted for within this approach, and that there is strong evidence for the existence of the baryonic fireball having a temperature of approx. 50 MeV.
Abstract: In the general framework of the fireball model, we analyze the observed momentum spectra of protons and light nuclei produced in high-energy particle-nucleus and nucleus-nucleus collisions. We demonstrate that the data including the well-known phenomena of cumulative effect can be naturally accounted for within this approach, and that there is strong evidence for the existence of the baryonic fireball having a temperature of approx. 50 MeV. We also present our qualitative picture of the baryonic spectra at high energies and consider a thermodynamic description of highly excited nuclear matter in the context of analyzing the relative yield of the light fragments in heavy ion collisions.
TL;DR: In this paper, the (d, 6 Li) α-cluster pickup reaction on targets of 144 Nd, 148 Sm, 152 Gd, 208 Pb, 232 Th and 238 U at bombarding energies from 33 MeV to 55 MeV were analyzed and the results compared with the known α-decay properties of these targets.
Journal Article•
TL;DR: In this article, the difference in nuclear attenuation of different hadrons produced in deep inelastic scattering of leptons from nuclear targets is sensitive to the composition of the intermediate state in nuclear matter.
Abstract: It is shown that the difference in nuclear attenuation of different hadrons produced in deep inelastic scattering of leptons from nuclear targets is sensitive to the composition of the intermediate state in nuclear matter. Measurements of attenuation should not only allow to determine if the high-energy component of this state is a quark or a hadron, but also give information on quark absorption cross-section and on time scale of hadronization.
01 Mar 1980
TL;DR: In this article, the energy dependent real and imaginary part of the nucleus-nucleus optical potential in a lab was calculated using a Bethe-Goldstone equation that includes the Pauli blocking caused by the two Fermi spheres and takes account of the presence of the other nucleons by their mean field.
Abstract: We calculated the energy dependent real and imaginary part of the nucleus-nucleus optical potential in a lab. energy domain between 50MeV and 225MeV per nucleon for the systems12C-12C and58Ni-58Ni. In our model we assume that the energetical behaviour of the colliding nucleons inside of the two overlapping nuclei is locally that of two colliding nuclear matter systems. Therefore the effective nucleon-nucleon interaction is calculated using a Bethe-Goldstone equation that includes the Pauli blocking caused by the two Fermi spheres and takes account of the presence of the other nucleons by their mean field. Neglecting finite range effects one can calculate the real and imaginary part by a folding procedure.
TL;DR: The pion-nucleon σM-term contribution to the S-wave π-N interaction leads to a modification of the PCAC hypothesis in nuclear matter as mentioned in this paper.