We use the continuum random phase approximation to describe the muon capture on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${,}^{16}$O, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. We reproduce the experimental total capture rates on these nuclei to better than 10% using the free nucleon weak form factors and two different residual interactions. However, the calculated rates for the same residual interactions are significantly lower than the data if the in-medium quenching of the axial-vector coupling constant is employed.

The neutron capture cross sections of ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$, ${}_{}{}^{135}{}_{}{}^{}\mathrm{Ba}$, ${}_{}{}^{136}{}_{}{}^{}\mathrm{Ba}$, and ${}_{}{}^{137}{}_{}{}^{}\mathrm{Ba}$ were measured in the energy range from 5 to 225 keV at the Karlsruhe 3.75 MV Van de Graaff accelerator. Neutrons were produced via the ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ (p,n${)}^7$ Be reaction by bombarding metallic Li targets with a pulsed proton beam. Capture events were registered with the Karlsruhe 4π barium fluoride detector. The cross section ratios were determined with an overall uncertainty of ∼3%, an improvement by factors of 5 to 8 compared to existing data. Severe discrepancies were found with respect to previous results. As a new possibility in time of flight experiments, isomeric cross section ratios could be determined for ${}_{}{}^{135}{}_{}{}^{}\mathrm{Ba}$, ${}_{}{}^{136}{}_{}{}^{}\mathrm{Ba}$, and ${}_{}{}^{137}{}_{}{}^{}\mathrm{Ba}$. Maxwellian averaged neutron capture cross sections were calculated for thermal energies between kT=10 keV and 100 keV. These stellar cross sections were used in an s-process analysis. For the s-only isotopes ${}_{}{}^{134}{}_{}{}^{}\mathrm{Ba}$ and ${}_{}{}^{136}{}_{}{}^{}\mathrm{Ba}$ the ${\mathit{N}}_{\mathit{s}}$〈σ〉 ratio was determined to 0.875±0.025. Hence, a significant branching of the s-process path at ${}_{}{}^{134}{}_{}{}^{}\mathrm{Cs}$ can be claimed for the first time, in contrast to predictions from the classical approach. This branching yields information on the s-process temperature, indicating values around ${\mathit{T}}_8$=2. The new cross sections are also important for the interpretation of barium isotopic anomalies, which were recently discovered in SiC grains of carbonaceous chondrite meteorites. Together with the results from previous experiments on tellurium and samarium, a general improvement of the ${\mathit{N}}_{\mathit{s}}$〈σ〉 systematics in the mass range A=120–150 is achieved. This yields a more reliable separation of s- and r-process contributions for comparison with stellar observations, but reveals a 20% discrepancy with respect to the solar barium abundance.

The first measurement of a lifetime for a superdeformed (SD) state that decays to normally-deformed (ND) states is reported for the 257-keV transition in the ${}_{}{}^{192}{}_{}{}^{}\mathrm{Hg}$ SD band. The measured lifetimes of this state and a state decaying by a 300-keV transition are 4.5 and 2.9 ps, respectively. These values correspond to the same collective E2 decay strength as the higher-spin states. The amplitude of the wave function corresponding to the ND shape is derived from these lifetimes and the branching ratios to the ND states. The derived variation of the barrier penetrability as a function of angular momentum is discussed and compared with similar estimates for other superdeformed systems.

Elastic scattering of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ particles from ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ was measured at 150 MeV/nucleon. The data were well reproduced by the single folding potential model without an anomalously large reduction for the potential depth.

Transient field precessions of the first excited states in ${}_{}{}^{50}{}_{}{}^{}\mathrm{Cr}$ have been measured. The states were excited by the inverse ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${(}^{40}$Ca, 2p${)}^{50}$Cr reaction and the recoil nuclei traversed a thick gadolinium foil, where they experienced the rotation. The observed precessions, for the $2^{+}$,$4^{+}$,$6^{+}$,$8^{+}$ states of the ground-state band, were equal within experimental error indicating these states have g factors similar to that of the $2^{+}$ state value of 0.55±0.10 measured previously. This feature is contrary to the predictions of the shell model and suggests a higher collectivity for the ground-state band. Limited results were also obtained for the cross conjugate nucleus ${}_{}{}^{46}{}_{}{}^{}\mathrm{Ti}$ supporting this conclusion.

The ${\mathit{Q}}_{\mathrm{\beta }}$ value for the β decay of ${}_{}{}^{84}{}_{}{}^{}\to _{}^{84}{}_{}{}^{}$Se has been measured for the first time. The value of 7195±200 keV is in disagreement with the value of 9780 keV derived from systematics. However, it is in agreement with results inferred from sums of average β and γ decay energies reported for decay heat measurements.

A semiclassical simulation is made for the reaction ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$(35 MeV/nucleon)${+}^{40}$Ca. The experimental fragment charge dispersion in the reaction is reproduced reasonably. Time evolutions of the fragment charge dispersion and of the average square of the component of particle momentum seem to indicate that the nuclear system formed in the intermediate energy nucleus-nucleus collisions might approach thermal equilibrium in the case of nearly central collisions.

The recent observation that the empirical threshold for fission hindrance correlates with the ratio of the threshold temperature to the temperature dependent fission barrier height is interpreted in terms of Bohr-Wheeler theory. A total fission delay of (2–4) times 10 sup -2— s is deduced from the empirical value of this ratio.

An optical model analysis of the quasielastic scattering of ${}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{14}{}_{}{}^{}\mathrm{Be}$ on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ target nuclei has been performed, for measurements at 679 and 796 MeV laboratory incident energy, respectively. The data are from the group of the University of Notre Dame. The automatic searches on the optical model parameters were constrained by fitting the total reaction cross sections to values extrapolated from measurements performed at much higher incident energy. It has turned out for both projectiles that a surface term is necessary for the real as well as for the imaginary part of the potential, in order to reproduce correctly the experimental data. This diffractive-refractive behavior favors the existence of a neutron halo for both projectiles.

The elastic scattering observables for 400 MeV ${\mathrm{\pi }}^{\pm }$ on ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ are calculated using a relativistic impulse approximation Kemmer-Duffin-Petiau formalism to calculate the ${\mathrm{\pi }}^{\pm }$ nucleus optical potential, and the Kemmer-Duffin-Petiau wave equation of motion with the aforementioned potential. The results are compared with recent experiments and with the results of nonrelativistic impulse approximation treatments.

The polarization observables in the elastic scattering of polarized deuterons on a polarized hydrogen target, with measurement of the recoil proton polarization, are considered. The observables are calculated in the one-nucleon exchange approximation, for the special case of backward scattering (${\mathrm{\theta }}_{\mathrm{c}.\mathrm{m}.\mathrm{}}$=180°). Several new relations between polarization observables of the reaction are derived within the framework of this approximation. These relations can be used for detailed study of the deuteron structure and/or deuteron interaction at intermediate energy.

Half-lives and α-branching ratios for the members of the ground-state ‘‘band’’ in ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$ are deduced using an α-cluster model. The α-core potential is obtained from a double folding procedure and has integral values close to those obtained in elastic α scattering. The preformation probability is found to be P=0.035. The long half-life of the (${18}^{+}$) isomer is explained by the prediction of the excitation energy of the ${16}^{+}$ state to lie above the (${18}^{+}$) isomer. The (${11}^{\mathrm{-}}$) and (${13}^{\mathrm{-}}$) at ${\mathit{E}}_{\mathit{x}}$=2411.3 and 2771.8 keV are tentatively assigned to the negative parity α-cluster ‘‘band.’’

The three-cluster generator coordinate method is used to investigate the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$${(}^3$He,2p${)}^4$He and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$${(}^3$H,2n${)}^4$He reactions at low energies. The three-body exit channels are simulated by distortion effects in the wave functions. We test the model through the experimental ${}_{}{}^3{}_{}{}^{}\mathrm{He}$${+}^3$He elastic cross sections, and discuss the different contributions to the S factors. We show that, in the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$${(}^3$He,2p${)}^4$He cross section, the (α+p)+p sequential breakup dominates the α+(p+p) process. A systematic search for resonances in ${}_{}{}^6{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^6{}_{}{}^{}\mathrm{He}$ is carried out, but we do not find any evidence for a new resonance.

A general and concise formalism is presented for the identification and evaluation of observables, including those that would indicate parity-conservation and/or time-reversal violation by the neutron-nucleus interaction, of experiments on the transmission of polarized neutrons through polarized nuclear targets. Statistical tensors are used for the description of the polarization states of the projectile and target, and the neutron-nucleus total cross section is decomposed into partial cross sections so that each corresponds to different ranks of the projectile and target statistical tensors and to a specific transfer of the orbital angular momentum. Each such partial cross section is associated with a ‘‘correlation factor’’ of particular parity-conservation and time-reversal symmetries, and is measurable by polarizing the projectile and target in states in which the statistical tensors have specific geometries, suggested by the simple geometric properties of the correlation factors.

A superdeformed band has been observed in the N=80 nucleus ${}_{}{}^{145}{}_{}{}^{}\mathrm{Tb}$ which was produced with the reactions ${}_{}{}^{112}{}_{}{}^{}\mathrm{Sn}$${(}^{37}$Cl,2p2n) and ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$${(}^{31}$P,4n) at bombarding energies of 187 and 160 MeV, respectively. Since superdeformed bands also exist in the three lighter N=80 isotones ${}_{}{}^{142}{}_{}{}^{}\mathrm{Sm}$, ${}_{}{}^{143}{}_{}{}^{}\mathrm{Eu}$, and ${}_{}{}^{144}{}_{}{}^{}\mathrm{Gd}$, it is now possible to understand the valence-proton configurations of these bands in a systematic way. The ${\mathcal{T}}^{\mathrm{}\left(2\right)\mathrm{}}$ dynamic moment of inertia in ${}_{}{}^{145}{}_{}{}^{}\mathrm{Tb}$ shows no evidence for the N = 6 quasiproton crossing that is observed in ${}_{}{}^{144}{}_{}{}^{}\mathrm{Gd}$. Comparison with cranked Woods-Saxon and total Routhian surface calculations suggests that the proton configuration in ${}_{}{}^{145}{}_{}{}^{}\mathrm{Tb}$ is $6^1$⊗[404${]}_{9/2^{+}}^2$ in which the quasiproton crossing is blocked. Furthermore, like ${}_{}{}^{143}{}_{}{}^{}\mathrm{Eu}$ and ${}_{}{}^{142}{}_{}{}^{}\mathrm{Sm}$, there is no evidence in the T${\mathrm{}}^{\mathrm{}\left(2\right)\mathrm{}}$ for the N=6 quasineutron crossing predicted by the calculations. This may indicate that static neutron pairing correlations are quenched at the N=80 superdeformed shell closure.

Nucleon resonances beyond the Δ(1232) have been observed in complex nuclei. Measurements of the (e,${\mathit{e}}^{\mathcal{’}}$p${\mathrm{\pi }}^{\mathrm{-}}$) reaction, at an incident energy of 14.5 GeV with 1.1 GeV <W<2.0 GeV and 〈${\mathit{Q}}^2$〉≊0.35 ${\mathrm{GeV}}^2$/${\mathit{c}}^2$, are presented for ${}_{}{}^2{}_{}{}^{}\mathrm{H}$, CO, Ar, and Xe targets. These exclusive data show no shift in the Δ(1232) mass and give evidence for excitations in the region of the ${\mathit{D}}_{13}$(1520) and ${\mathit{F}}_{15}$(1680) resonances. The pion angular distribution in the Δ region is suppressed at forward angles relative to distorted-wave impulse approximation predictions.

New calculations are presented for Gamow-Teller beta decay of nuclei near ${}_{}{}^{100}{}_{}{}^{}\mathrm{Sn}$. Essentially all of the ${}_{}{}^{100}{}_{}{}^{}\mathrm{Sn}$ Gamow-Teller decay strength is predicted to go to a single state at an excitation energy of 1.8 MeV in ${}_{}{}^{100}{}_{}{}^{}\mathrm{In}$. The first calculations are presented for the decays of neighboring odd-even and odd-odd nuclei which show, in contrast to ${}_{}{}^{100}{}_{}{}^{}\mathrm{Sn}$, surprisingly complex and broad Gamow-Teller strength distributions. The results are compared to existing experimental data and the resulting hindrance factors are discussed.

A method of truncating the large shell model basis is outlined. It relies on the order given by the unperturbed energies of the basis states and on the constancy of their spreading widths. Both quantities can be calculated by a simple averaging procedure. The method is tested in the sd shell where the JT dimensions are of the order of a few thousand. It proves to be very effective in the middle of the fp shell where JT dimensions of the order of a few times ${10}^6$ are truncated to a few times ${10}^3$.