The high-spin structure of ${}_{}{}^{139}{}_{}{}^{}\mathrm{Sm}$ has been investigated with the ${}_{}{}^{110}{}_{}{}^{}\mathrm{Pd}$${(}^{34}$S,5n) reaction at a beam energy of 159 MeV at the Stony Brook Tandem/Superconducting LINAC facility. The TESSA3 spectrometer array was used to collect γ-γ coincidence data from which an extended decoupled band structure has been found. It is proposed that this band is based on the ${\mathit{i}}_{13/2}$ (Ω=1/2) neutron intruder orbital. The decay pattern, enhanced dynamic moments of inertia, and aligned spins are consistent with the ν${\mathit{i}}_{13/2}$ bands in neighboring odd-neutron nuclides. Total Routhian surface and cranked shell model calculations reproduce qualitative features of these nuclides, further supporting the proposed interpretation.

The reactions ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${(}^{36}$Ar,α2p${)}^{88}$Mo and ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${(}^{36}$Ar,4p${)}^{90}$Mo at 149 and 140 MeV beam energies have been used to carry out Doppler shift attenuation and recoil distance lifetime measurements and to determine DCO ratios in ${}_{}{}^{88}{}_{}{}^{}\mathrm{Mo}$ and ${}_{}{}^{90}{}_{}{}^{}\mathrm{Mo}$. A singles angular distribution experiment using the reaction ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$${(}^{35}$Cl,3p${)}^{90}$Mo has been performed at 120 MeV beam energy to measure spin assignments in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Mo}$ and to calibrate the DCO analysis for both nuclei. Reduced transition probabilities for more than 60 transitions in ${}_{}{}^{88,90}{}_{}{}^{}\mathrm{Mo}$ have been reduced. The extensive data set is incorporated in a detailed comparison between the two nuclei and, for ${}_{}{}^{90}{}_{}{}^{}\mathrm{Mo}$, with predictions from shell model calculations within a restricted π(${\mathit{p}}_{1/2}$),π(${\mathit{g}}_{9/2}$),ν(${\mathit{p}}_{1/2}$), and ν(${\mathit{g}}_{9/2}$) configuration space and with different residual interaction parameters. The electromagnetic properties of the negative parity states of ${}_{}{}^{90}{}_{}{}^{}\mathrm{Mo}$ are well reproduced by the calculations while the positive parity states show hints of seniority mixing at intermediate spins.

The deformation properties of the low-lying magnetic dipole excitations, known as scissors mode, are systematically studied within the framework of the generalized coherent state model. The present description is shown to be closely related to other interacting boson approaches as well as to the geometrical two-rotor model. The results are in good agreement with experiments and consistent with those obtained in other phenomenological as well as microscopic approaches.

In order to try to open a new scope to explore the mutual dependence between the single-particle and collective modes of motion near to the level crossing region, a general method is developed to investigate the nonlinear resonant structure of the time-dependent Hartree-Fock (TDHF) manifold, without depending on the adiabatic assumption. By using the Lie canonical transformation method with the Deprit perturbation treatment, in this method, the maximal integrable-form representation of the TDHF manifold is introduced. This representation plays an essential role in exploring the nonlinear resonant structure of the TDHF manifold, which characterizes complex topology of the manifold. Aiming at relating the nonlinear resonance in the TDHF manifold with the dynamics between the single-particle and collective modes of motion near to the level crossing region, structure of the TDHF wave function in the nonlinear resonant region is investigated. It is clarified that an isolated nonlinear resonant region of the TDHF manifold is characterized by a local constant of motion (dynamical symmetry) and generates a new type of dynamical stable single-Slater-determinant states, which is topologically different from the TDHF states near the HF ground state, and cannot be reached by the conventional static Hartree-Fock method, constrained Hartree-Fock method, nor the adiabatic TDHF theories. One may expect that the appearance mechanism of the new dynamical stable single-Slater-determinant states gives us a new scope for understanding occurrence mechanism of a variety of collective sideband structure near to the level crossing region.

A new kind of cluster quasieleastic knockout experiment is proposed based on the generalized distorted wave impulse approximation calculation which uses Glauber-Sitenko multiple scattering theory and takes into account deexcitation of virtual excited clusters in the nucleus. Elements of general formalism are presented, including the discussion of the difference between ‘‘fast’’ and ‘‘slow’’ cluster processes. The reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(p,pα${)}^8$Be is considered in detail. It shows a strong dependence of the ‘‘effective momentum distribution’’ of knocked-out cluster on both the scattering angle of fast proton and orientation angles of recoil momentum q with respect to the direction of the incident beam and to the scattering plane of a fast proton (i.e., ${\mathrm{\Theta }}_{\mathit{q}}$ and ${\mathit{cphi}}_{\mathit{q}}$ anisotropies). Experiments of this kind are desirable also for electron-induced cluster knockout. Finally, the possibility of observing ${\mathrm{\Theta }}_{\mathit{q}}$ and ${\mathit{cphi}}_{\mathit{q}}$ anisotropies in ${}_{}{}^2{}_{}{}^{}\mathrm{H}$(e,e’p)${\mathit{N}}^{\mathrm{*}}$ and ${}_{}{}^1{}_{}{}^{}\mathrm{H}$(e,e’${\mathrm{\pi }}^{+}$)n reactions at a few GeV energies due to the quark deexcitation effects is discussed.

The detailed study of the reaction pp→pp${\mathrm{\pi }}^0$ was carried out at seven energies of the incident proton in the region 600–900 MeV. Energy spectra, angular, and effective mass distributions were analyzed. The analysis was performed in the framework of the one-pion exchange model. Taking into account only the ${\mathit{P}}_{33}$ wave in the pole diagrams allows one to obtain good agreement with experimental data on various differential distributions. At the same time the predictions for total cross sections are much lower than the experimental data.

Nucleon correlation effects on the natural orbitals obtained by the generator coordinate method and the coherent density fluctuation model are considered. The single-particle potentials corresponding to the natural orbitals are calculated and discussed.

We examine the question of whether the fourth and fifth structure functions (called ${\mathrm{W}}_{\mathrm{LT}}$ and ${\mathrm{W}}_{\mathrm{LT}\prime }$) defined by the plane wave Born approximation (PWBA) for the reaction (e,e′p) are still meaningful quantities in the presence of electron Coulomb distortion. For a heavy target (${\mathrm{Pb}}^{208}$), the apparent structure functions obtained in the presence of the electron Coulomb distortion have shapes (in terms of the number of maxima or minima) similar to those defined in PWBA; however, the magnitudes are changed greatly. For the fourth structure function, the distortion can change the magnitude, even for ${\mathrm{O}}^{16}$, by more than 15%. For proton knockout from (l±12) spin-orbit doublet states, the changes caused by electron distortion have opposite effects, increasing the magnitude of the one while decreasing the other. The Coulomb effects on the fifth structure function depend on the out of plane angle used in the extraction. For a small angle (e.g., 10°), the electron distortion can be more than 15% in ${\mathrm{O}}^{16}$. However, for certain kinematic choices, the Coulomb distortion effects on the fifth structure function can largely be removed. For proton knockout from spin-orbit doublet states the ratio of the fifth structure functions is of interest. We find that this ratio is nearly independent of the central part of the proton final state interaction and has the power of investigating the spin-orbit interaction of optical potentials.

The strong variation in energy of the first excited $0^{+}$ state in the even-even Ge isotopes is investigated with pairing type interactions in various model spaces. Although it had been possible in previous work to describe this variation in a BCS–random-phase-approximation (RPA) calculation in the neutron configuration only, the corresponding exact diagonalization disagrees with the BCS-RPA results and experiment. It is furthermore shown that the behavior of the first excited $0^{+}$ state cannot be obtained by a reasonable variation of parameters in the exact neutron pair calculations. This suggests that the model space be enlarged to include proton, neutron, and proton-neutron pairing. The construction of the corresponding basis is then simplified by performing a boson mapping and employing the ideal collective boson basis. This, however, may lead to the occurrence of spurious states, even at fairly low energies, and three separate methods by means of which they can be identified are discussed. Although the enlarged model space gives a desired lowering of excitation energy of the first excited $0^{+}$ states in an exact diagonalization, the strong experimental variation could not be achieved with this simple interaction. Nevertheless, the analysis yields further and new insight into applications of boson mappings, specifically about how and when spurious states may be identified in calculations which are performed in a truncated space not invariant under a given collective algebra.

We generalize the Skyrme force by making its spin-orbit component density dependent. One of the two extra parameters thereby introduced is fixed by performing Hartree-Fock calculations on semi-infinite nuclear matter, and comparing with relativistic Hartree calculations performed on the same system in the nonlinear σ-ω model. In this way an essential feature of the relativistic theory is incorporated into the nonrelativistic framework of Skyrme forces.

The neutron halo structure of ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ and of ${}_{}{}^8{}_{}{}^{}\mathrm{He}$ is studied in a microscopic three-body and five-body model, respectively. Various cluster arrangements are included to embody a variety of correlations between the clusters. The intercluster wave function is determined with the stochastic variational method. The ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^8{}_{}{}^{}\mathrm{He}$ energies are reproduced with the same effective force very well. The radii and densities are compared with the results of empirical analyses. The calculated difference of the neutron and proton radii exceeds 0.8 fm, confirming the thick neutron skin. The two-neutron removal spectroscopic amplitudes are calculated and used for evaluating the momentum distribution and the β decay spectrum, which are sensitive to the halo structure. A fair agreement with experiment is obtained.

The influence of neutron-proton correlations on backbending is investigated in a single-j-shell model. It is shown that these correlations are quenched if the neutrons and protons fill a high-j intruder orbital asymmetrically. This is due to the repulsive neutron-proton correlation energy in these configurations and is responsible for the observed forking of the ground state band into proton and neutron S bands.

We treat ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, and ${}_{}{}^{56}{}_{}{}^{}\mathrm{Ni}$ as systems of baryons which can exist in either the ground (nucleon) state or first excited (delta) state and follow their behavior under static comrpession using constrained spherical Hartree-Fock approximation (SHF). We use realistic effective nucleon-nucleon interactions with meson-exchange-based nucleon-delta transition potentials and delta-delta interactions and we make phenomenological adjustments to obtain SHF equilibrium properties in agreement with experiment. We then show how physical properties are affected by delta excitation under compression. We find that a significant fraction of the increase in energy of these nuclei under compression is stored in the form of Δ-mass creation. This, in turn, may have implications for an enhanced role for nuclear compression in subthreshold pion production in nucleus-nucleus collisions. In addition, including the deltas leads to a lower compressibility of each of these nuclei.

In this work correlated basis functions theory is applied at the lowest order to analyze the ground state and low energy spectrum of light (p-shell) nuclei. The study is an extension of a previous work devoted to the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ nucleus and includes state-dependent correlations, whose radial components are determined by solving a set of Euler-Lagrange equations. The matrix elements are computed by using a cluster expansion. Results of calculations performed using ${\mathit{v}}_{14}$ nucleon-nucleon potentials are presented and compared with the results obtained for ${\mathit{v}}_8$ potentials.

Exact diagonalizations with a minimally modified realistic force lead to detailed agreement with measured level schemes and electromagnetic transitions in ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Sc}$, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{48}{}_{}{}^{}\mathrm{V}$, ${}_{}{}^{48}{}_{}{}^{}\mathrm{Cr}$, and ${}_{}{}^{48}{}_{}{}^{}\mathrm{Mn}$. Gamow-Teller strength functions are systematically calculated and reproduce the data to within the standard quenching factor. Their fine structure indicates that fragmentation makes much strength unobservable. As a by-product, the calculations suggest a microscopic description of the onset of rotational motion. The spectroscopic quality of the results provides strong arguments in favor of the general validity of monopole corrected realistic forces, which is discussed.

Calculations of polarized neutron-polarized ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ scattering are presented for the transverse and longitudinal total cross-section differences Δ${\mathrm{\sigma }}_{\mathit{T}}$ and Δ${\mathrm{\sigma }}_{\mathit{L}}$ in the energy range ${\mathit{E}}_{\mathit{n}}$=0.1 to 10 MeV. Predictions made from phase-shift analyses, R-matrix analysis, and a multichannel resonating group-model calculation are compared. The predictions are in qualitative agreement and show that polarized neutron-polarized ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ scattering is sensitive to the level structure of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ in the excitation energy range 20–30 MeV.

Assuming the length of the 3π cut to be finite and approximating the integrated 4π amplitude by a constant, we derive an expression for the πNN¯ form factor which is very close to that given by a simple pole. The specific predictions of the obtained form factor for the region of small momentum transfer are compared with existing effective pole formulas and discussed along the lines of the Goldberger-Treiman relation.

We reexamine the long-standing problem of the microscopic derivation of a particle-core coupling model. We base our research on the Klein-Kerman approach, as amended by Dönau and Frauendorf. We describe the formalism to calculate energy spectra and transition strengths in some detail. We apply our formalism to the rotational nuclei ${}_{}{}^{155,157}{}_{}{}^{}\mathrm{Gd}$, where recent experimental data requires an explanation. We find no clear evidence of a need for Coriolis attenuation, though such an effect may be masked by the use of a quadrupole-quadrupole coupling strength as a fitting parameter.

The angular patterns of fragments produced in central heavy-ion collisions at intermediate bombarding energies, and observed in emulsion experiments, are analyzed through simulations based on a molecular dynamical approach. The results indicate that these angular patterns give information on the shape of the multifragmenting system at relatively early stages of the collision process.

Single-particle states in ${}_{}{}^{41}{}_{}{}^{}\mathrm{Ca}$ have been investigated through the Ca(d→,p${)}^{41}$Ca reaction with polarized deuterons of ${\mathit{E}}_{\mathit{d}}$=56 MeV. Angular distributions of differential cross sections and vector analyzing powers were measured for 91 transitions up to 9.7-MeV excitation energy by using a magnetic spectrograph. Analyses of these data were performed to determine ${\mathit{j}}^{\mathrm{\pi }}$ and ${\mathit{C}}^2$S of single-particle levels with zero-range distorted-wave Born approximation calculations using the adiabatic approximation. The occupation probabilities and the single-particle energies in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ were extracted for the valence (2p-1f) and (2s-1d) shells with including previous (p,d) data. The results on these quantities show good agreement with theoretical expectations.