It is shown that there exists a simple relationship between the ground band energies of even-even nuclei spanning a wide region of mass (A≃76–254) and equilibrium shape, and their valence nucleon numbers (${\mathit{N}}_{\mathit{p}}$,${\mathit{N}}_{\mathit{n}}$). This relationship enables us to deduce much useful information about the equilibrium shape of a particular nucleus just from the knowledge of its ${\mathit{E}}_{21}^{+}$ energy and to predict the excitation energies of even-even nuclei belonging to this mass region with reasonable accuracy.

By introducing a three-body interaction among the d bosons into the Hamiltonian of the interacting boson model, the difficulties concerning the energy spacing between different τ and with the staggering phenomenon in the O(6) dynamical symmetry are surmounted in more or less degree. So the energy spectra of the O(6)-like nuclei are improved, and some E2 transitions which are forbidden in O(6) limit become allowed due to this three-body potential. The energy spectra and B(E2) values of some even-even nuclei are calculated. The theoretical values agree with the experimental data fairly well.

Characteristics of Λ, Σ, and Ξ hypernuclei are investigated within the relativisitic mean-field theory. The spin-orbit splitting is very sensitive to the value of tensor coupling ${\mathit{f}}_{\mathrm{\omega }\mathit{Y}}$. A self-consistent treatment together with elimination of the hyperon self-coupling contribution is crucial for determining the ${\mathit{V}}_{\mathrm{\rho }}$ contribution to the hyperon binding.

We examine the data on the giant monopole resonance in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and the information on the charge and neutron density differences in ${}_{}{}^{208}{}_{}{}^{}\mathrm{-}_{}^{207}{}_{}{}^{}$Pb and ${}_{}{}^{208}{}_{}{}^{}\mathrm{-}_{}^{206}{}_{}{}^{}$Pb to obtain a constraint on the nuclear compression modulus K. We employ the two-channel linear response theory in which the self-consistency relation between the mean field and the residual interaction is included. Two Skyrme-type interactions with substantially different values of K are used. It is demonstrated that the breathing mode energy, being dependent on properties of the interaction in the interior region, is more sensitive to K than the density differences. This analysis indicates values of K in the range K=210–250 MeV.

The effect of the pairing interaction coming from the rotationally induced ${\mathit{K}}^{\mathrm{\pi }}$=$1^{+}$ pair-density on the nuclear moments of inertia is studied. It is pointed out that, contrary to the situation at normal deformations, the inclusion of the ${\mathit{K}}^{\mathrm{\pi }}$=$1^{+}$ pairing may appreciably modify the frequency dependence of the moments of inertia at superdeformed shapes.

It is shown that a τ-dependent compression of energy levels occurs in most SO(6)-like nuclei, where τ is the SO(5) quantum number. We suggest that this compression represents a generalization of the Coriolis antipairing effect to symmetries other than SU(3), and that it is effectively described by an SO(6)-plus-pairing model.

We point out that the proton-neutron residual interaction is able to account for the recently observed properties in the empirical interaction energies between the last odd proton and neutron in nuclei adjacent to closed shells. Using zero-range forces, the specific difference between the average particle-particle and particle-hole interaction matrix elements is the major factor. We extend the arguments to cover also nuclei with two valence proton and two valence neutron configurations outside of a closed shell (we treat both two-particle two-particle, two-hole two-hole, and two-particle two-hole situations). Here we derive the particular binding energy contribution due to the proton-neutron interaction and give applications to heavy nuclei.

Calculations have been made to explore the effect of configuration mixing in a large basis on the fragmentation of ‘‘stretched’’ M6 strength in the sd-shell nuclei ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$. This work extends a study made for N=Z sd-shell nuclei to midshell N≠Z nuclei with the same Hamiltonian and basis restriction, one particle in the 1${\mathit{f}}_{\mathrm{\tau }/2\mathrm{}}$ orbit and unrestricted occupancy of the sd-shell orbits, used in that earlier work. It is found that configuration mixing in this large basis gives a very good description of the total isovector strength seen in ${}_{}{}^{26}{}_{}{}^{}\mathrm{Mg}$ but fails to give a detailed description of the experimental spectra. Results for fragmentation of the isoscalar response are less conclusive because of conflicts between data sets.

The tensor polarization of the recoil deuteron in elastic electron-deuteron scattering has been measured at the Bates Linear Accelerator Center at three values of four-momentum transfer Q=3.78, 4.22, and 4.62 ${\mathrm{fm}}^{\mathrm{-}1}$, corresponding to incident electron energies of 653, 755, and 853 MeV. The scattered electrons and the recoil deuterons were detected in coincidence. The recoil deuterons were transported to a liquid hydrogen target to undergo a second scattering. The angular distribution of the d→-p scattering was measured using a polarimeter. The polarimeter was calibrated in an auxiliary experiment using a polarized deuteron beam at the Laboratoire National Saturne. A Monte Carlo procedure was used to generate interpolated calibration data because the energy spread in the deuteron energies in the Bates experiment spanned the range of deuteron energies in the calibration experiment. The extracted values of ${\mathit{t}}_{20}$ are compared to predictions of different theoretical models of the electromagnetic form factors of the deuteron: nonrelativistic and relativistic nucleon-meson dynamics, Skyrme model, quark models, and perturbative quantum chromodynamics. Along with the world data the structure functions A(Q) and B(Q) are used to separate the charge monopole and charge quadrupole form factors of the deuteron. A node in the charge monopole form factor is observed at Q=4.39±0.16 ${\mathrm{fm}}^{\mathrm{-}1}$.

A segmented focal plane detector has been used to study the breakup of 87 MeV ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$ ions incident on a ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ target into ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ fragments at relative energies between 0 and 4 MeV. The relative energy spectra are dominated by sequential breakup of the 9.28 MeV, 10.26+10.33 MeV, and 10.60 MeV excited states in ${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$. The measured breakup yields decrease with increasing center-of-mass scattering angle, consistent with predictions made using single-step inelastic distorted wave Born approximation calculations. Applications of this technique to study the breakup of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at low relative energies will be discussed.

Angular correlations between deuterons and alphas in the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{14}$N,d${)}^{24}$${\mathrm{MG}}^{\mathrm{*}}$(α${)}^{20}$Ne(g.s.) at beam energies of 30, 33, 36, and 42 MeV have been used to investigate the reaction mechanism. Evidence for possible ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ cluster transfer to the 13.45 MeV $6^{+}$ state in ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ is presented. The transfer of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$($2^{+}$) clusters seems to be the dominant process. In addition to the correlation measurements, deuteron angular distributions were measured at 33 and 42 MeV and an excitation function at a lab angle of 8° was obtained between 30 MeV and 45 MeV in 3 MeV steps. The angular correlations, deuteron angular distributions, and the excitation function were fitted using the finite range distorted wave Born approximation (FRDWBA) and the Hauser-Feshbach formalism of compound nucleus formation.

Antiproton-induced fission has been investigated with a novel double-arm fission fragment spectrometer. Inclusive distributions of total mass, individual mass, and total kinetic energy of the fragments, and of the momentum of the fissioning nucleus, were measured. A dynamical model which takes into account all stages of p¯-induced fission (atomic cascade, intranuclear cascade, evaporation cascade, fission of compound nucleus, evaporation from fission fragments) was formulated for the first time. In particular, the dynamics of the descent of fissioning nuclei from saddle point to scission point are described by the diffusion model. The data on p¯-induced fission were analyzed in the framework of this model and good agreement between experiment and theory was obtained.

The total cross sections for ${\mathit{K}}^{+}$ on deuterium, ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ have been measured at four-momenta in the range of 480–714 MeV/c. The experimental technique was of the standard transmission type. Because of its long mean free path in nuclear matter at low energies the ${\mathit{K}}^{+}$ can be expected to probe the entire volume of the nucleus. Indeed we found that, to better than 10% σ(${\mathit{K}}^{+}$A)=Aσ(${\mathit{K}}^{+}$N) up to A=40. This feature was used to study more delicate effects of the nuclear medium. Special emphasis was placed on measuring the total cross section ratios of ${\mathit{K}}^{+}$A to ${\mathit{K}}^{+}$ D with a precision of ≤2%. This ratio is a good measure of nuclear medium effects because many experimental as well as theoretical systematic uncertainties cancel in the ratio. We discuss the medium dependence as a function of A. The data do not agree with calculations which include only conventional medium effects. This points towards the need of unconventional nuclear medium effects such as partial quark deconfinement, mass rescaling of nuclear pionic fields or pion excess in nuclei. Thus far only calculations based on unconventional medium effects for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ exist. Calculations for the other nuclei are needed before quantitative conclusions can be drawn.

One- and two-proton transfer reactions were studied at bombarding energies around the barrier in ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}$ + ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ and ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ + ${}_{}{}^{68}{}_{}{}^{}\mathrm{Zn}$ systems. The decrease of one- and two-proton stripping probabilities with the distance of closest approach was observed to be slower than that expected from semiclassical considerations, at above barrier energies, especially for two-proton stripping. The effect of these transfer channels on the sub-barrier fusion enhancement was investigated on the basis of semiclassical theories. It was found that the couplings to the inelastic channels and the one- and two-proton transfer channels cannot explain the observed enhancement, indicating the importance of the one- and two-neutron transfer channels in explaining the fusion data.

The reaction cross section for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(γ,pd) has been measured using the Saskatchewan-Alberta Large Acceptance Detector (SALAD) with tagged photons in the energy range from 166 to 213 MeV. The energy and angle of the proton and the deuteron were measured with SALAD while the tagger determined the photon energy. Differential cross sections have been determined for 40°<${\mathrm{\theta }}_{\mathit{p}}^{\mathrm{*}}$<150°. The results are in agreement with the Bonn and Saclay photodisintegration measurements. The most recent photodisintegration measurement performed at Bates is higher by a factor of 1.3, which is just within the combined errors of the experiments. The proton capture results differ by a factor of 1.7 from the present experiment. Comparisons are made with microscopic calculations of the cross sections.

We establish the applicability of a microscopic coupled-channel theory to pion inelastic scattering from rotational nuclei for the purpose of studying details of neutrons and proton densities. The theory is completely specified as a result of our taking the second-order pion-nucleus optical potential from previous phenomenological studies of elastic and charge-exchange data on spherical nuclei and of our using nuclear wave functions obtained from a Hartree-Fock + BCS calculation with the Skyrme ${\mathrm{SKM}}^{\mathrm{*}}$ interaction. Making multipole expansions leads to a set of coupled equations, which is solved for the scattering cross sections in a standard manner. Numerical studies are presented for the specific nucleus ${}_{}{}^{152}{}_{}{}^{}\mathrm{Sm}$. The theory is shown to be stable with respect to truncation of the expansions: we find rapid convergence of the cross sections for elastic scattering and inelastic scattering to the first $2^{+}$ and $4^{+}$ states as transition densities of successively higher multipolarity are added, and as the number of coupled rotational nuclear levels is increased. Medium modifications are included and have a small but significant effect on the cross section: for scattering to the $2^{+}$ state, their effect is about 10% for both ${\mathrm{\pi }}^{\mathrm{-}}$ and ${\mathrm{\pi }}^{+}$. We also quantify the extent of sensitivity of pion scattering cross sections to variations in the size and shape of the neutron and proton distribution using parametrized Woods-Saxon forms for the density.

We consider the reaction ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$${+}^{197}$Au at incident ${}_{}{}^{36}{}_{}{}^{}\mathrm{Ar}$ energies of 35, 50, 80, and 110A MeV, comparing calculations of precompound decay using the Boltzmann master equation (BME) and quantum molecular dynamics (QMD) models. We then estimate quasiequilibrated nuclei and excitations using the BME, and use these values as input into statistical multifragmentation models. For the latter we compare sequential binary decay as an extension of the Weisskopf-Ewing evaporation model, and a simultaneous multifragmentation for an expanded low density gas. The exclusive multiplicities predicted by these models are compared with experimental results.

A procedure to connect a model-independent phase-shift analysis with the solution of the inverse quantum scattering problem has been developed and applied to experimental differential cross sections of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${+}^{12}$C elastic scattering in the energy range ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=8–12 MeV. The minimization of the error square function ${\mathrm{\chi }}^2$ is performed with respect to the spectral coefficients involved in the inverse procedure. Input quantities are measured differential cross sections; output results are complex potentials. The real part of the potentials, so obtained, is characterized by a pronounced minimum value of -(7–14) MeV at relative distances in the range 2.4–3 fm and by a Coulomb barrier of height 6–7 MeV in the outer region around r≊8–9 fm. In addition a second minimum, very shallow or vanishing at some incident energies, is found to exist in the region 5–6 fm. The imaginary part of the potential exhibits positive maxima in those regions of radial distances where the real part has minimum values indicating a possible feedback effect of flux to the elastic channel. The overall energy dependence of the potentials shows a shape transition resulting in diminishing the outer potential minimum between ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$ of 9 and 12 MeV. The inverted (real) potentials yield phase shifts of π/2 in those partial waves where resonances are known to exist. The procedure is tested by recalculating differential cross sections from the inverted energy-dependent potentials with the result that consistent agreement with the experimental input data is found.

The occurrence of orbiting and fusion-fission processes observed experimentally in some light and medium-light heavy-ion collisions at incident energies well above the Coulomb barrier are discussed in the framework of a number of available open channels calculation. The fusion-fission mechanism appears to be less competitive in systems for which the available phase space for the highest partial waves is restricted to a few exit channels where dinuclear configurations can survive through orbiting trajectories. The coexistence of quasimolecular resonances, orbiting mechanisms, and the fusion-fission process for medium-light dinuclei is also briefly discussed.

We introduce an adiabatic expansion to derive a formula for a macroscopic quantum tunneling probability that takes the mass renormalization due to the coupling to fast environmental degrees of freedom into account. The formula is applied to studying the effects of nuclear vibrational excitations on the fusion cross section in heavy-ion collisions at energies below the Coulomb barrier. It is shown that mass renormalization plays an important and useful role to discuss the effects of vibrational excitations of moderate energy. Also a general proof is given to show that the renormalized part of the effective mass appearing in our formula is the cranking mass.