The nuclear equation of state is calculated using the soliton bag model and the Wigner-Seitz approximation for baglike states on a lattice. Since the Wigner-Seitz treatment averages over lattice structure, it is more realistic for a fluid like nuclear matter than is a periodic crystal model. A crucial feature of the model presented here is the manner of filling the Bloch band of independent particle states: We argue for a dilute filling of the entire band. Quark wave functions sigma field configurations, and energies are calculated as a function of baryon density. The energies are only qualitatively similar to semiempirical nuclear energies. Within the context of this crude model, we find a first-order phase transition corresponding to a nuclear matter phase which sets in at about six times normal density and a plasma phase at roughly 12 times normal nuclear density.

We present a parameter that provides a unified interpretation of the $3_1^{\mathrm{-}}$ states of a large number of spherical and weakly deformed Z>28 nuclei. This parameter suggests criteria for identifying nuclei having anomalous octupole behavior.

Isoscalar convection currents for nuclei with one valence particle or hole outside a closed-shell core are studied in the mean-field (Hartree) approximation to the Walecka model. The currents are constructed using nucleon wave functions computed in the self-consistent potentials of the spherical core. Approximate self-consistency for the full odd-A nucleus is imposed by using linear response theory to correct the core wave functions for the effects of the valence nucleon. At low q, this core response cancels the enhancement of the isoscalar current that arises from the reduced effective mass of the valence nucleon so that magnetic moments are close to the Schmidt predictions. In contrast, particle-hole mixing in the core response enhances the single-particle current further at higher q. Calculations of magnetic moments and elastic magnetic scattering in light nuclei are presented to illustrate these results. The relationship of these calculations to fully self-consistent mean-field solutions of odd-A nuclei and to the linear response function in nuclear matter is discussed.

We show that the reliability of theoretical estimates of the admixture of collective zero-point fluctuations in the nuclear ground state is currently limited by uncertainties in the effective nucleon-nucleon interaction and the existence of double-counting corrections arising from various sources. The issues are illustrated in a model calculation that includes some of the corrections and we find results that are considerably smaller than those recently reported in the literature. Pion scattering is suggested as an appropriate tool for experimentally constraining theoretical uncertainties in these pieces of the density.

We study a relativistic model of the nucleus consisting of nucleons coupled to mesonic degrees of freedom via an effective Lagrangian whose parameters are determined by a fit to selected nuclear ground-state data. We find that the model allows a very good description of nuclear ground-state properties. Because of the relativistic nature of the model, the spin properties are uniquely fixed. We discuss variations of the parametrization and of the data which suggest that the present fit has exhausted the limits of the mean-field approximation, and discuss extensions which go beyond the mean field.

A model is proposed in which we take full advantage of both the shell and cluster models in order to describe a system of valence nucleons weakly coupled to a core. This is realized by introducing radius vectors of the valence nucleons relative to the core, new coordinates of independent particle nature. The model is applied to the neutron-rich He isotopes, ${}_{}{}^{6\mathrm{-}8}{}_{}{}^{}\mathrm{He}$, with reasonable success.

The influence of symmetry-preserving third-order interaction terms in the Hamiltonian of the interacting boson model [O(6) limit] on the theoretical energy spectrum, on absolute and relative B(E2) values, and on the quadrupole moment of the first excited state is discussed. A comparison between theoretical and experimental data is made for the nucleus ${}_{}{}^{196}{}_{}{}^{}\mathrm{Pt}$.

The sdg interacting-boson model is presented in the SU(3) tensor formalism. The interactions are decomposed according to their SU(3) tensor character. The existence of the SU(3)-seniority preserving operator is found to be important. The model is applied to ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$. Energy levels and electromagnetic transitions are calculated. This model is shown to solve the problem of anharmonicity regarding the excitation energy of the first $K^{\pi }$${=4\mathrm{}}^{+}$ band relative to that of the first $K^{\pi }$${=2\mathrm{}}^{+}$ one. E4 transitions are calculated to give different predictions from those by the quasiparticle-phonon nuclear model.

In deformed Hartree-Fock calculations with Skyrme interactions we observe a near degeneracy of the mean energies of many-particle–many-hole deformed intrinsic states. For example, in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ the np-nh states with n=2, 3, 4, 5, 6, 7, and 8 are nearly degenerate. The deformation parameter β increases steadily from n=2 to 8. The intrinsic state energy of the 8p-8h state is lower than that of the 4p-4h state for the interactions used here—SK III, SK IV, and SK VI. The calculations are also performed with the Skyrme III interaction for the even-even calcium and titanium isotopes. For ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ti}$ there is a near degeneracy of 6p-2h and 8p-4h. For the N>Z isotopes above, the two protons excitation lies lowest. Whereas the intrinsic state energies are much higher than the observed energies of the lowest-lying deformed states, the results when projection of J${=0\mathrm{}}^{+}$ states is carried out and pairing effects are taken into account, are encouraging.

The homogeneous version of Coulomb modified Faddeev equations was used to determine the binding energy of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. In the ${}_{}{}^1{}_{}{}^{}\mathrm{S}_0^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{S}_1^{}{}_{}{}^{}$${\mathrm{-}}^3$${\mathrm{D}}_1$ subsystem states, a separable representation of the Paris potential was taken for the N-N interaction; whereas less sophisticated separable potentials were employed in the P and D partial waves with j≤2. The influence of these latter higher N-N partial waves on the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ binding energy was calculated for the first time within the nonperturbative Faddeev equation approach. The trinucleon binding energy differences were found to be compatible with Coulomb energies obtained in the framework of perturbation theory with local N-N potentials.

A complete derivation of a new two-variable integrodifferential equation valid for three- and many-boson systems is given here for the first time, and it is shown to be exact if all correlations higher than those of two-body type can be neglected. Its equivalence to the Faddeev equation for three bodies and its applicability to many-body systems are discussed in detail. Three-body forces are included. It is shown that the three- and four-body binding energies obtained by means of this equation are in good agreement with those obtained from the most sophisticated variational, Faddeev, and Faddeev-Yakubovsky calculations. This indicates that our new two-variable integrodifferential equation should also be useful for larger systems, in particular since unlike other methods it does not suffer from the disadvantage of rapidly increasing complexity with A. We also show that a simple adiabatic method for the solution of this equation (and hence also for the Faddeev equation) is quite sufficient, due to the closeness of the upper and lower bounds obtained in this way. Finally we apply the adiabatic method to nuclear three-body scattering and even include the effect of breakup for spin-dependent forces. It is found that asymptotic behavior is reached for a value of the hyperradius of the order of 35 fm.

A new semiempirical method that significantly simplifies atomic mass systematics and which provides a method for making mass predictions by linear interpolation is discussed in the context of the nuclear valence space. In certain regions complicated patterns of mass systematics in traditional plots versus Z, N, or isospin are consolidated and transformed into linear ones extending over long isotopic and isotonic sequences.

In this paper we present the theory of nuclear matter in the framework of relativistic nuclear field theory utilizing the technique of relativistic many-body Green’s functions. The analytic properties of the Green’s functions and related quantities are given and used to obtain the final set of equations for the nuclear matter problem. In detail, we have investigated theoretically and numerically the so-called ${\Lambda }^{00}$ and ${\Lambda }^{10}$ approximations. For comparison we also calculated the relativistic Hartree-Fock and the Brueckner-Hartree-Fock approximation, respectively. For masses and coupling strengths we used (phenomenological) parameter sets given by the Bonn and Groningen group. The results of the Λ approximations are similar to the relativistic Brueckner treatment.

It is shown that the isotopic variation in charge radii for selected nuclei in the 50≤N,Z≤82 region can be described in a shell model framework using a semirealistic effective interaction.

A weak-coupling description of intruder states valid throughout the periodic table is presented. Calculations for the even-mass Hg, Pb, and Po isotopes, and for the odd-mass Au, Tl, Bi, and At isotopes are compared with experiment. A new prescription to obtain monopole neutron-proton interactions is described. The special case of shape transition in the neutron-rich Zr isotopes is also considered. The present model unifies different descriptions used in literature to treat pairing vibrations.

Fermi statistics require that all quarks in a nucleus be antisymmetrized, and hence that quarks belonging to different nucleons be exchanged in proportion to the degree of nucleon overlap. This leads to a shift in the distribution of quark momentum relative to that in isolated nucleons, and hence to a shift in the structure function $F_2$(x). This paper extends previous work on the European Muon Collaboration (EMC) effect for the trinucleon system to systems with large numbers of nucleons. For large N, certain divergences were encountered and traced to contributions arising from unlinked quark clusters. After renormalization a smooth N→∞ limit was obtained. The conclusion derived in the previously considered N=3 case is upheld: Quark exchange is very important—perhaps even dominant—in calculating the deviation away from unity of the ratio of the nuclear structure function to that of a free nucleon.

A two-component Pauli equation for a composite model of the nucleon is derived using a relativistically covariant quark model. Scalar-isoscalar, vector-isoscalar, vector-isovector, and electromagnetic external potentials are considered. For the vector fields we find anomalous ‘‘magnetic moments,’’ which are simply related to the corresponding electromagnetic κ. The Dirac equation, even if supplemented by anomalous magnetic moments, is found to fail beginning with the Darwin term. However, in Dirac phenomenology, the low-order errors can be compensated by the strengths and functional shapes of the assumed potentials.

We analyze the possible bifurcations of the stationary points of the self-consistent flow on the Bloch sphere. We propose a generalized SU(2) model Hamiltonian for which, by means of a geometrically simple classification, we find the topologically invariant regions of the mean field flow in the space of interaction parameters. The borders of these regions are the bifurcation sets corresponding to general nonthermodynamic phase transitions. When these separatrices are crossed, the mean field flow undergoes a qualitative change. We also examine the consequences of the catastrophical configurations on the exact dynamics in quasispin space.

Using one of the recent Bonn potentials, an energy- and density-dependent interaction for nucleon-nucleus scattering is derived by solving the Bethe-Goldstone equation for two nucleons interacting in the presence of infinite nuclear matter at several incident energies below 425 MeV. Some of the approximations involved in the construction of the effective interaction are discussed and several of its dynamical properties are examined. Selected properties of the present interaction are also compared with those of a similar G-matrix interaction based on the Paris potential as well as with those of a recent t-matrix interaction based directly on nucleon-nucleon phase shifts. The role of medium corrections as well as the utility of the present interaction are studied by applying it to a variety of transitions in nucleon-nucleus scattering where important constraints on the transition densities are available from electron scattering.

The proton-oxygen bremsstrahlung cross sections have been measured at a bombarding energy of 2.74 MeV and at a scattering angle of 155°, for photon energies between 40 and 200 keV. The measured spectrum agrees well with the prediction of the Feshbach-Yennie approximation.