Observables of elastic neutron-deuteron scattering are calculated within the framework of the Alt-Grassberger-Sandhas (AGS) three-nucleon equations. As input we use the separable W-matrix representation of the two-body T matrix of the Paris potential. We present a criterion based on the Schmidt norm of the kernel of the AGS equations to optimize this representation. Comparing with an almost complete set of experimental observables, except for a few observables depending sensitively on input not yet fully optimized in this manner, our results generally show good agreement with the data. We thus corroborate previous findings for semirealistic potentials also for realistic interactions, namely that the W-matrix approach provides a very efficient means of calculating three-nucleon scattering processes. Estimates are given showing that this method requires at least an order of magnitude less computational resources than other solution algorithms, without sacrificing accuracy.

Excitation functions of the reactions ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{16}$O${,}^8$Be${)}^{20}$Ne and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{16}$O${,}^4$He${)}^{24}$Mg leading to several states have been measured in the range ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=25.7–38.6 MeV. From cross channel correlation analysis two intermediate resonance structures at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=26.9 and 29.5 MeV corresponding to excitation energies of 43.7 and 46.2 MeV in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ have been identified. Angular distribution measurements for ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{16}$O${,}^4$He${)}^{24}$${\mathrm{Mg}}_{\mathrm{g}.\mathrm{s}.\mathrm{}}$ have also been made at the lower resonance at ${\mathit{E}}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=26.9 MeV which enable spin assignment of ${\mathit{J}}^{\mathrm{\pi }}$=${14}^{+}$ to this resonance. Striking observation of preferential ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ decay of both the resonances to the 8-particle–4-hole states in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ is interpreted as evidence for the resonances to be highly deformed shape isomeric configurations in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ expected from deformed shell-model calculations.

High spin states in ${}_{}{}^{129}{}_{}{}^{}\mathrm{Pr}$ and ${}_{}{}^{131}{}_{}{}^{}\mathrm{Pr}$ have been investigated using in-beam γ-ray spectroscopy techniques. The yrast band of ${}_{}{}^{129}{}_{}{}^{}\mathrm{Pr}$ based on the ${\mathit{h}}_{11/2}$ 3/$2^{\mathrm{-}}$[541] proton configuration was observed from 11/$2^{\mathrm{-}}$ up to 43/$2^{\mathrm{-}}$. The band based on the same configuration and two positive-parity side bands based on the ${\mathit{g}}_{7/2}$ 5/$2^{+}$[413] proton configuration, were observed in ${}_{}{}^{131}{}_{}{}^{}\mathrm{Pr}$. The delayed yrast band crossing of ${}_{}{}^{129}{}_{}{}^{}\mathrm{Pr}$ at ħ${\mathrm{\omega }}_{\mathit{c}}$=0.37 MeV is interpreted as being due to the alignment of the second and third ${\mathit{h}}_{11/2}^{\mathrm{-}}$ protons. The band crossing at ħ${\mathrm{\omega }}_{\mathit{c}}$=0.26 MeV, with a gain in alignment of about 8ħ, based on the ${\mathit{g}}_{7/2}$ 5/$2^{+}$[413] configuration in ${}_{}{}^{131}{}_{}{}^{}\mathrm{Pr}$ was attributed to the alignment of two ${\mathit{h}}_{11/2}$ protons. The systematics of the proton alignments in a series of Pr isotopes is discussed.

We have measured inclusive γ-ray spectra from the reactions α${+}^{48}$Ti${\to }^{52}$Cr and ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$${+}^{27}$Al${\to }^{46}$Ti, populating final states at moderate temperature and spin. These spectra were analyzed using a statistical model including giant resonance strength functions in the γ-decay width. The parameters of the giant dipole resonance (GDR) strength function were varied to fit the data. Two different level-density formulations were utilized—one (Pühlhofer) in which the level-density parameters were adjusted to obtain the best overall fit to the data, and the other (Reisdorf) which contained no free parameters. While the magnitudes of the extracted GDR parameters differed in the two cases, their dependence on final-state energy was similar. The GDR energy was observed to be nearly constant with the final-state energy, and the GDR strength exhausted nearly a full E1 sum rule. In the α${+}^{48}$Ti reaction, the GDR width was observed to increase slightly with increasing bombarding energy. In the ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$${+}^{27}$Al reaction, a pronounced GDR width increase was observed with increasing bombarding energy and was attributed to an increase in compound nucleus spin. These results are consistent with current calculations based on the rotating liquid-drop model and with recent experimental reports.

Chemically purified and mass-separated Rn isotopes are used to deduce the α branching ratios of the Po daughter nuclei. The obtained values are systematically lower than the previously known values. Combined with more accurate measurements of the half-lives of the neutron-deficient Po isotopes, a precise set of partial α-decay half-lives is obtained. The α-decay energies of some Po and Rn isotopes have also been remeasured. The α branching ratios of the Rn nuclei can be deduced from the α intensity of the At daughter nuclei, provided their branching is known. This makes it possible to present in a coherent way the partial α-decay half-lives and the α-reduced widths of a long chain of Po and Rn isotopes and to compare them with theory. Evidence is emerging that, for the very neutron-deficient Po isotopes, mixing of intruder configurations into the ground state is slowing down the α decay.

We have measured the beta-delayed proton spectrum arising from ${}_{}{}^{25}{}_{}{}^{}\mathrm{Si}$ produced in the ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$${(}^3$He,2n) reaction. Utilization of a new low-energy proton detector has permitted the observation of protons from 250 to 6000 keV. Most proton groups have been placed into a decay scheme by using penetrability calculations and transitions from the mirror beta decay, ${}_{}{}^{25}{}_{}{}^{}\to _{}^{25}{}_{}{}^{}$Mg. This placement permits the construction of the Gamow-Teller strength function which we compare to a beta strength function calculated from complete-space s-d shell model wave functions.

Previous measurements of the half-life of ${}_{}{}^{32}{}_{}{}^{}\mathrm{Si}$, which is produced by cosmic-ray spallation of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$ and of interest for geophysical dating, display large discrepancies. We present a new method for half-life measurements of this and other isotopes. Two samples containing 6.7×${10}^8$ and 7.4×${10}^8$ ${}_{}{}^{32}{}_{}{}^{}\mathrm{Si}$ nuclei, respectively, were prepared by implantation of separated projectile fragments. The half-life of ${}_{}{}^{32}{}_{}{}^{}\mathrm{Si}$ was calculated from the two independent measurements of the specific activity to be 132±13 yr.

Resonances were observed in the continuum in pion-induced double charge exchange (at ${\mathit{T}}_{\mathrm{\pi }}$=295 MeV) on ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ at Q=-14.0, -32.4, and -48.0 MeV, on ${}_{}{}^{115}{}_{}{}^{}\mathrm{In}$ at Q=-25.0, -37.3, and -49.6 MeV, and on ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ at Q=-35.0, -44.3, and -54.9 MeV. The three resonances have different characteristic angular distributions. Partial angular distributions were measured on ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ and ${}_{}{}^{115}{}_{}{}^{}\mathrm{In}$ and observed to have ${\mathit{J}}^{\mathrm{\pi }}$=$0^{+}$, $1^{\mathrm{-}}$, and $2^{+}$ shapes, respectively. Based on their centroid energies, angular distributions, and observed cross sections, we identify the resonances as the double isobaric analog state, the giant dipole built on the isobaric analog, and the double giant dipole resonance. The new observations are in close agreement with the gross features reported recently for the double giant resonances, and provide some of the best signals obtained to date for the double resonance states in nuclei.

Measurements of the linear polarization of resonantly scattered photons have been used for model independent parity assignments in nuclear resonance fluorescence experiments (NRF). Previous NRF investigations of the even-even Nd isotopes were completed by polarization measurements on the transitional nucleus ${}_{}{}^{146}{}_{}{}^{}\mathrm{Nd}$. With these new parity assignments the systematics of low lying M1 strengths can be studied along the transition from spherical to deformed nuclear shapes. The total M1 strength in the excitation energy range of 2–4 MeV in the investigated even-even Nd isotopes increases proportionally to the square of the deformation parameter. These findings represent a reliable confirmation of the results recently reported for the Sm isotopes by the Darmstadt group. This deformation dependence can be explained by various recent theoretical approaches.

We evaluate pionic decay widths of Λ hypernuclei using shell-model nuclear wave functions and distorted pion waves. We investigate the effects of the final-state interaction of the pion, consider decay into nuclear bound states and the continuum for the nucleons, and make an accurate study of the energy balance in the reaction. The results obtained confirm many previous findings but also modify appreciably previous results, mostly as a consequence of the accurate treatment of the energies involved in the reaction.

The size of the proton subshell gap between the ${\mathit{d}}_{5/2}$ and ${\mathit{h}}_{11/2}$ orbitals is reviewed. The need of revising the microscopic calculations with increased energy gap is reexamined for N≥82 nuclei. Both for occupation probabilities and the nuclear structure of N=82 isotones and the ${}_{}{}^{146\mathrm{-}154}{}_{}{}^{}\mathrm{Sm}$ isotopes, the increased gap at Z=64 is not inconsistent with experiment, except that increased quadrupole strength is required for obtaining the same structure. The use of alternative values of boson numbers in the interacting boson model (IBM) for N<88 nuclei is investigated. In a phenomenological IBM calculation there is no a priori need of the use of subshell closure. In the empirical studies for this region the use of the Z=64 subshell does lead to elegant systematics in some cases but it also leads to inconsistencies in other cases. Dependence of collective deformation effect on the slope of particular orbitals, rather than on gap size only, is illustrated.

The method of multidimensional scaling has been applied to sets of proton capture γ-ray spectra in ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ and ${}_{}{}^{30}{}_{}{}^{}\mathrm{P}$, allowing the attribution of spins to a number of resonances in each nucleus. The utility of this method of simultaneous comparison of many resonance decay branching patterns appears to depend on the variety of final state spins. In the case of ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$, where the spin discrimination is good, some selectivity by parity and isospin also occurs.

Model fits were made to the cumulative distribution of all known levels (with spins J≤10) in ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ below an excitation energy of 4.1 MeV identified in a variety of experiments, and simultaneously to the density of J=0 and J=1 resonances inferred from neutron capture and total cross-section measurements in ${}_{}{}^{115}{}_{}{}^{}\mathrm{Sn}$+n. Neither the back-shifted Fermi-gas model nor the constant-temperature model provides a satisfactory fit over the entire energy range. The generalized superfluid model, with a level-density parameter and a spin-cutoff factor that are both energy dependent, does give a good fit, and the resulting best-fit parameter values are consistent with those found in other applications of this model.

We have calculated the binding energies, rms radii, and multipole moments of Ho isotopes (N=81–98) using a relativistic mean field theory. The quadrupole moments and the change in mean square charge radius are compared with the experimental and other theoretical results. We observed a shape transition from oblate to prolate deformations in going from lighter to heavier isotopes.

We study the effect of the momentum dependence on the thermal properties of excited dilute nuclear matter in the Boltzmann approximation. The optical potential, mean field, k mass, pressure, and incompressibility are calculated. We improve on an earlier approximate treatment and find, in most cases, relatively small quantitative differences in the behavior of the calculated observables. An exception is the k mass, which acquires a temperature dependence in the improved approximation. Phase diagrams for nuclear matter are presented and the transition of hadronic matter to quark-gluon plasma is studied.

Electric dipole moments are extracted from data for E1 transitions deexciting octupole vibration states in nineteen nuclei. The moments are then compared to values calculated using the droplet model prescription of Dorso, Myers, and Swiatecki. It is found that the E1 moments in quadrupole deformed nuclei can be reproduced with the droplet model using the same model parameters that reproduce atomic masses and fission barriers. This result supports the suggestion of Butler and Nazarewicz that single particle effects are usually much smaller than macroscopic effects in E1 transitions associated with octupole vibrations in reflection symmetric deformed nuclei.

We study relativistic nuclear matter in the σ-ω model including the ring-sum correlation energy. The model parameters are adjusted self-consistently to give the canonical saturation density and binding energy per nucleon with the ring energy included. Two models are considered, mean-field theory where we neglect vacuum effects, and the relativistic Hartree approximation where such effects are included but in an approximate way. In both cases we find self-consistent solutions and present equations of state. In the mean-field case the ring energy completely dominates the attractive part of the energy density and the elegant saturation mechanism of the standard approach is lost, namely, relativistic quenching of the scalar attraction. In the relativistic Hartree approach the vacuum effects are included in an approximate manner using vertex form factors with a cutoff of 1–2 GeV, the range expected from QCD. Due to the cutoff, the ring energy for this case is significantly smaller, and we obtain self-consistent solutions which preserve the basic saturation mechanism of the standard relativistic approach.

Energy spectra, spectroscopic factors and electromagnetic moments of the low-lying states of ${}_{}{}^{120\mathrm{-}124}{}_{}{}^{}\mathrm{Sb}$ have been calculated in the framework of the interacting boson-fermion-fermion model, and compared with the experimental values. It was found that the collectivity has a significant effect on the energy splitting of the multiplets. The dynamical boson-fermion interaction leads to a smoothing of the energy splitting, while the exchange interaction tends to cause a fourth order polynomial splitting in the ${\mathit{E}}^{\mathrm{*}}$ versus J(J+1) plot. The smoothing of the energy splitting can be interpreted in a quasiparticle picture as the lengthening of the range of the p-n effective interaction. The collective and single particle effects have comparable contributions in the electromagnetic moments, and the single particle part of the transfer operator determines the spectroscopic factors.

The analysis of the interacting fermion models with the SU(2) symmetry indicates the different behavior of the splittings of opposite-parity lowest-energy eigenstates for even and odd numbers of fermions. The imaginary time-dependent mean-field approach reproduces the average results only. For the odd particle numbers, an introduction of the universal logarithmic term to the action integral is needed. The even-odd effect appears in a wide class of models with the SU(2) symmetry and is connected with the crossing of the energy surfaces of opposite-parity states for an odd number of fermions.

Inclusive yields of isotopically resolved intermediate-mass fragments (IMF) with Z=3–6 have been measured for the reaction of E/A=50 MeV ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ with ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ and ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$ targets. The isotopic yield patterns reflect the N/Z ratio of the target for both equilibriumlike and nonequilibrium components of the spectra. In addition, the IMF elemental cross sections for the ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$ target decrease much more rapidly with Z than for ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$. This effect is presumably due to lower barriers for IMF emission from residues formed with the neutron-deficient ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$ target and increased competition from pre-IMF neutron emission for the neutron-excess ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$ target. The experimental cross sections are compared with statistical and accreting-source calculations.