In previous work we have constructed an effective interaction for use in Dirac-Hartree-Fock calculations of the structure of finite nuclei. Our goal has been to study the properties of finite nuclei using an effective interaction which is derived from an interaction that fits the free-space nucleon-nucleon scattering data. In this work we report of the results of our calculations for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. We have performed these calculations in momentum space and have maintained translational invariance in our analysis. We find a good representation of the charge density of these nuclei and some degree of underbinding, which, in part, reflects the underbinding of nuclear matter for the one-boson-exchange potentials whose reaction matrices are simulated by our effective interaction. (Comparison is made to the recent work of Müther, Machleidt, and Brockman, who have performed a Dirac-Brueckner-Hartree-Fock calculation of the properties of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$.)

The comparison between effective Hamiltonians, constructed within the framework of symmetry restoring methods, is discussed for the case of intrinsic two-quasiparticle excitations in superfluid nuclei. Particularly, the meaning of currently adopted approximations, i.e., number symmetry restoring effective interactions and ideal quasiparticle representation in gauge space, is discussed in connection with an intrinsic symmetry breaking mechanism in the number variable.

Finite temperature bosonic contributions to the nuclear level density parameter are calculated. The adopted formalism is based on the random-phase approximation treatment of particle-particle, hole-hole, and particle-hole channels of an isospin-independent δ force. The particle-particle (hole-hole) channels are renormalized and they are treated together with the particle-hole channels. Random-phase approximation contributions to the level density parameter are found to display low-temperature features which are similar to the ones that are due to the collapse of pairing correlations.

Self-consistent relativistic Hartree calculations of odd-A nuclei, including vacuum polarization, are presented. The contribution to the baryon current from the deformed Dirac sea is calculated using a derivative expansion. This vacuum current does not affect magnetic moments; however, at intermediate momentum transfers it tends to cancel the current from the deformed occupied core, as expected from the random-phase approximation response in nuclear matter. Wave function mixing for the valence state, which arises in the self-consistent solution but not in random-phase approximations, significantly affects both Dirac and anomalous currents.

The 1/N expansion method, which is an angular momentum projected mean field theory, is used to investigate the nature of electromagnetic transitions in the interacting boson model. Conversely, comparison with the exact interacting boson model results sheds light on the range of validity of the mean field theory. It is shown that the projected mean field results for the E2 transitions among the ground, β, and γ bands are incomplete for the spin-dependent terms, and it is essential to include band mixing effects for a correct (Mikhailov) analysis of E2 data. The algebraic expressions derived are general and will be useful in the analysis of experimental data in terms of both the sd and sdg boson models.

A new representation of the many-particle configuration space in the cranked shell model for well deformed nuclei is introduced. The single-particle states and the many-particle configurations are chosen as the simultaneous eigenstates of ${\mathit{J}}_{\mathit{z}}^2$ and ${\mathit{R}}_{\mathit{x}}$(π), a rotation of 180° about the x axis. The K structure of the low-lying eigenstates of the cranked shell model Hamiltonian ${\mathit{H}}_{\mathrm{CSM}}$ is investigated in detail. It is shown that the accurate solutions to the low-lying bands of ${\mathit{H}}_{\mathrm{CSM}}$ can be obtained easily by using a K truncation. The reduction in dimension of the many-particle configuration space achieved by the K truncation is quite considerable and the eigenstates obtained by using a suitable K truncation are almost identical to those obtained without K truncation.

Core excited states in ${}_{}{}^{210}{}_{}{}^{}\mathrm{Po}$ and ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ are studied in terms of correlated two-particle and particle-hole states within the framework of the multistep shell-model method. All possible two-particle and particle-hole states within the chosen single-particle levels are included in the calculation. It is found that most observed states can be explained in terms of only one correlated particle-hole state coupled to a correlated two-particle (or two-hole) state. Good agreement with available experimental data is obtained and level schemes are proposed in both nuclei including states that have not yet been observed.

The projection operator onto the physical space is investigated in the boson expansion techniques. An explicit expression for the projection operator contains many body terms. From this expression, recurrent relations are obtained. Based on the properties of the projection operator, a new general form of boson mapping is derived.

Via the inelastic scattering of 50 MeV/nucleon ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ ions, the giant quadrupole resonance in ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ and ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ has been investigated to test experimentally a newly proposed relationship between the centroid and width of the giant quadrupole resonance and the neutron binding energy of the nucleus. Our results do not confirm the proposed relationship.

The ${}_{}{}^2{}_{}{}^{}\mathrm{H}$${(}^6$Li${,}^3$Heα)n reaction was studied at energies between 21.6 and 33.6 MeV in kinematical conditions for the quasifree ${}_{}{}^1{}_{}{}^{}\mathrm{H}$${(}^6$Li${,}^3$He${)}^4$He reaction. The energy dependence of the quasifree cross section for small neutron momenta was compared with the excitation function of the free two-body reaction.

The exact evaluation of one-loop corrections in a finite (1+1)-dimensional system is described. Scalar and vector (baryon) densities are calculated in a background of Gaussian scalar and vector potentials. The results are compared with a derivative expansion in inverse powers of the effective mass. Excellent agreement is found when derivative terms up to second order are retained.

We investigate a dependence of the ‘‘old’’ European Muon Collaboration (EMC) effect on nuclear structure, namely the dependence on the location of the struck quark within a nucleus (‘‘local’’ EMC effect). The EMC effect is examined by the rescaling model and also by the nuclear binding model. We find that they give similar results in the sense that scattering from a central or deeply bound constituent gives a larger EMC effect than scattering from a surface or weakly bound constituent. If accurate experimental data become available, these interesting effects could be investigated in detail.

The contribution of the two-body exchange currents to the nonweighted sum rule of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is calculated for momentum transfer between 300 and 700 MeV/c. It is found that the inclusion of the mesonic pair current modifies the sum by 0.4% to 11% depending on the value of the momentum transfer q and the specifics of the strong interaction form factor.

The kinematic and dynamic moments of inertia of several superdeformed bands are calculated as a function of the rotational frequency, treating self-consistently the nuclear deformation and including the effects of pairing correlations. The fingerprints of these correlations are seen even at the highest rotational frequencies.

Quantal size effects play a central role in the transition taking place, in strongly rotating nuclei, from pair-correlated to normal phases. The two conceptually different methods to treat these effects, namely, the random phase approximation and the number projection method, are applied to realistic situations implying both normal and superdeformed nuclei. Both approaches are found to give similar results.

An explanation is offered for the large fusion radii obtained in the optical model description of heavy-ion fusion given by Udagawa et al. An extension of the model is suggested, and possible effects on the spin distribution are discussed. It is contended that the large fusion radii cannot be deduced from the elastic scattering alone. The role of Coulomb excitation for these systems is also discussed.

Lifetimes of members of the superdeformed band in ${}_{}{}^{135}{}_{}{}^{}\mathrm{Nd}$ have been determined by a Doppler-shift attenuation method. In this case, where side feeding occurs along the entire length of the cascade, centroid analysis does not give a unique answer and line-shape analysis is necessary. We find a transition quadrupole moment of 7.4±1.0 b, corresponding to an axis ratio of 1.42. The side feeding is ∼4 times slower than the main cascade.

We have investigated the excitation and ground-state photon decay of the giant resonance region in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ due to inelastic scattering of 84 MeV/nucleon ${}_{}{}^{17}{}_{}{}^{}\mathrm{O}$. The inelastic spectra are dominated by the isovector giant dipole resonance. The spectra of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ are almost identical in the giant resonance region. We conclude that the resonance strength functions are very nearly the same for these nuclei. Significant differences are, however, found in the distribution of ground-state decay photons from the two nuclei. These differences appear to be due to a large contribution from decay of fully damped compound states in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$.

The parity- and isospin-forbidden ${\mathrm{\alpha }}_0$ decay from ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}_{}^{\mathrm{*}}{}_{}{}^{}$(${\mathit{J}}^{\mathrm{\pi }}$=$1^{+}$; T=1; ${\mathit{E}}_{\mathit{x}}$=13.482 MeV) to ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(g.s.) has been investigated by measurement of the longitudinal analyzing power ${\mathit{A}}_{\mathit{z}}$ of the reaction ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$(p→,${\mathrm{\alpha }}_0$${)}^{16}$O around the $1^{+}$ resonance in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}_{}^{\mathrm{*}}{}_{}{}^{}$. With the data, the range for the expected interference effect has been reduced to ${\mathit{A}}_{\mathit{z}}$=(15.0±7.6)×${10}^{\mathrm{-}4}$ (68% c.l.), significantly smaller than a previous result. An analysis for the new data and those of related experiments has been performed to extract upper limits for the irregular ${\mathrm{\alpha }}_0$ width ${\mathrm{\Gamma }}_{\mathrm{\alpha }0}^{\mathrm{PNC}}$ and the weak pion nucleon coupling constant ${\mathit{f}}_{\mathrm{\pi }}$, being smaller than previous theoretical expectations.