The interpretation of future precise experiments on atomic parity violation in terms of parameters of the standard model could be hampered by uncertainties in the atomic and nuclear structure. While the former can be overcome by measurement in a series of isotopes, the nuclear structure requires knowledge of the neutron density. We use the nuclear Hartree-Fock method, which includes deformation effects, to calculate the proton and neutron densities in ${\mathrm{Cs}}^{125}$–${\mathrm{Cs}}^{139}$. We argue that the good agreement with the experimental charge radii binding energies, and ground-state spins signifies that the phenomenological nuclear force and the method of calculation that we use is adequate. Based on this agreement, and on calculations involving different effective interactions, we estimate the uncertainties in the differences of the neutron radii δ〈${\mathrm{r}}^2$${\mathrm{〉}}_{\mathrm{N},\mathrm{N}\prime }$ and conclude that they cause uncertainties in the ratio of weak charges, the quantities determined in the atomic parity nonconservation experiments, of less than ${10}^{\mathrm{-}3}$. Such an uncertainty, although to some extent model dependent, is safely smaller than the anticipated experimental error.

The neutron capture cross sections of ${}_{}{}^{147,148,149,150,152}{}_{}{}^{}\mathrm{Sm}$ were measured in the energy range from 3 to 225 keV at the Karlsruhe Van de Graaff accelerator using gold as a standard. 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. Several runs were performed under different experimental conditions to study the systematic uncertainties in detail. For the first time, data were recorded with an ADC system that allows one to register gamma-ray energy and time of flight of the individual detector modules. The cross-section ratios were determined with an overall uncertainty of ∼1%. This is an improvement by about a factor of 5 compared to the existing data. Severe discrepancies were found with the results of previous measurements. Maxwellian-averaged neutron capture cross sections were calculated for thermal energies between kT=10 and 100 keV by normalizing the cross-section shape up to 700 keV neutron energy reported in literature to the present data. These stellar cross sections were used in an s-process analysis. The ratio of the values of the s-process current 〈σ〉${\mathit{N}}_{\mathit{s}}$ (Maxwellian-averaged neutron capture cross section times s-process abundance) for the s-only isotopes ${}_{}{}^{148,150}{}_{}{}^{}\mathrm{Sm}$ is 0.870±0.009 rather than unity as expected by the local approximation. The corresponding branching in the s-process path is analyzed in the framework of the classical approach. The resulting mean neutron density, ${\mathit{n}}_{\mathit{n}}$=(3.8±0.6)×${10}^8$ ${\mathrm{cm}}^{\mathrm{-}3}$, is the most stringent value obtained so far. Finally the new cross sections are used to derive constraints for a stellar model and to check recently discovered isotopic anomalies in meteoritic samarium.

Differential cross sections for ${}_{}{}^3{}_{}{}^{}\mathrm{\alpha }$ scattering were measured in the energy range up to 3 MeV. These data together with other available experimental results for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$+α and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$+α scattering were analyzed in the framework of the optical model using double-folded potentials. The optical potentials obtained were used to calculate the astrophysical S factors of the capture reactions ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(α,γ${)}^7$Be and ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(α,γ${)}^7$Li, and the branching ratios for the transitions into the two final ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ bound states, respectively. For ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(α,γ${)}^7$Be excellent agreement between calculated and experimental data is obtained. For ${}_{}{}^3{}_{}{}^{}\mathrm{H}$(α,γ${)}^7$Li an S(0) value has been found which is a factor of about 1.5 larger than the adopted value. For both capture reactions a similar branching ratio of R=σ(${\gamma }_1$)/σ(${\gamma }_0$)≊0.43 has been obtained.

Measurements of small-angle cross sections for the pion double-charge-exchange (DCX) reaction ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^{\mathrm{-}}$${)}^{16}$Ne (g.s.) at incident energies of 300–500 MeV are reported. These are the first measurements of DCX cross sections on a T=0 nucleus in this energy region. The behavior of the cross sections is similar to that of analog transitions, but they are smaller by more than an order of magnitude. This suggests sequential charge-exchange scattering as the dominant process, but suppressed by a mechanism not yet identified.

Highly polarized tagged photons were used to measure the distribution of M1 transition strength in ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$ at excitations between 5.5 and 6.9 MeV. The total M1 strength found in this energy range is consistent with that reported in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$. For the isoscalar state at 5.8 MeV in ${}_{}{}^{206}{}_{}{}^{}\mathrm{Pb}$, B(M1↑)=(0.72±0.15)${\mathrm{\mu }}_{\mathit{N}}^2$. Microscopic calculations are in good quantitative agreement with these results.

We have measured the absolute gamma-ray intensity, i.e., γ’s per 100 parent decays, of the 1266-keV line produced in ${}_{}{}^{31}{}_{}{}^{}\mathrm{Si}$ decay using neutron activation and delayed photon spectroscopy. Its value was determined to be 0.050±0.004%. This result is lower than the only previously reported value of 0.07, which was given without an uncertainty. In a separate experiment to validate the method of measurement and analysis, the gamma-ray intensity of the 1779-keV line of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Al}$ was determined to be 98±8.8%, in good agreement with its adopted value of 100%.

The origin of the large discrepancy existing between calculated values of the spin-isospin response functions and those observed by proton scattering experiments is investigated. We conclude from the results of several Hartree-Fock based random phase approximation calculations that nuclear structure effects play an important role in lowering the ratio of spin-longitudinal to spin-transverse response functions ${\mathit{R}}_{\mathit{L}}$/${\mathit{R}}_{\mathit{T}}$, in agreement with experiment. We find that the effective mass has a predominant influence in reducing ${\mathit{R}}_{\mathit{L}}$/${\mathit{R}}_{\mathit{T}}$.

It is shown that nucleon decay (instability) in a nucleus can be well studied by investigating nuclear deexcitations of the nucleon hole produced by the nucleon decay. Individual deexcitation modes and their branching ratios are given for nucleon holes associated with nucleon decays in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$.

The energy dependence of the fusion spin distribution has been studied in terms of its scaled moments. It is shown that the effect of channel coupling on spin distribution, particularly the effect of coupling of the shape degree of freedom to the translational motion, is much stronger at and above Coulomb barrier energies, even though the effect on fusion cross section is largest at sub-barrier energies.

We have calculated the binding energies, rms radii, and deformation parameters for light nuclei, and helium through oxygen with and without pairing correlations using deformed relativistic mean field approach with the NL2 parameter set. The effects of pairing for open-shell nuclei have been investigated. It is pointed out that the pairing is crucial to study the shapes of the nuclei.

Simple formulas for the $0^{+}$→$0^{+}$ double beta decay matrix elements, as a function of the particle-particle strength ${\mathit{g}}^{\mathit{p}\mathit{p}}$, have been designed within the quasiparticle random phase approximation. The 2ν amplitude is a bilinear function of ${\mathit{g}}^{\mathit{p}\mathit{p}}$, and all 0ν moments behave as ratios of a linear function and the square root of another linear function of ${\mathit{g}}^{\mathit{p}\mathit{p}}$. It is suggested that these results are of general validity and that any modifications of the nuclear Hamiltonian or the configuration space cannot lead to a different functional dependence.

Careful comparison of ${}_{}{}^{20}{}_{}{}^{}\mathrm{F}$ and ${}_{}{}^{20}{}_{}{}^{}\mathrm{Na}$, and available data on reactions leading to both, suggests that ${\mathit{J}}^{\mathrm{\pi }}$(2646)=$3^{+}$. Other mirror identifications are indicated and quantities of astrophysical interest are calculated.

Recent experimental double charge exchange cross sections to the double analog state and the ground state are compared to predictions of the generalized seniority model.

Alpha clustering is analyzed within a shell-model-like Berggren representation which includes the bound and outgoing single-particle resonant states of a realistic Woods-Saxon potential. It is found that the clustering of the alpha particle in ${}_{}{}^{212}{}_{}{}^{}\mathrm{Po}$, leading to α decay, can be described even for distances which are well beyond the surface of the daughter nucleus.

We investigate the influence of the short-range neutron-proton interaction on the deformation length in nuclei using a macroscopic approach for calculating the total neutron-proton interaction energy. Within this simple framework we show that for Fermi density distributions the minimum interaction energy is obtained with equal deformation lengths for neutrons and protons, while for Gaussian distributions equal deformations are required.

It is demonstrated that the search performed by Wieland et al. for the elusive $1^{\mathrm{-}}$ state in ${}_{}{}^{218}{}_{}{}^{}\mathrm{Ra}$ was not optimized and an alternative experiment is discussed. We demonstrate that existing data on Ra-Th nuclei and Sm-Gd nuclei raise further doubts on suggestions and implication of Wieland et al.

The reaction ${\mathrm{\pi }}^{\mathrm{-}}$p→${\mathrm{\pi }}^{+}$${\mathrm{\pi }}^{\mathrm{-}}$n was studied at a total c.m. energy of 1301 MeV. The incoming pion beam was focused on a liquid hydrogen target. For the ${\mathrm{\pi }}^{+}$ detection a large acceptance spectrometer was used whereas the outgoing ${\mathrm{\pi }}^{\mathrm{-}}$ was measured in a 4 sr detector arrangement. A collected set of 32 000 kinematical complete ${\mathrm{\pi }}^{\mathrm{-}}$p→${\mathrm{\pi }}^{+}$${\mathrm{\pi }}^{\mathrm{-}}$n events delivered invariant mass distribution and double differential cross sections as well as angular correlation functions and triple differential cross sections, respectively. The observables, showing a characteristic deviation from phase space, are compared with model calculations based on Weinberg’s Lagrangian. The dynamics of the reaction is well described. In addition, there are clear indications for the need of relativistic corrections, whereas the data do not justify strong contributions of σ- and ρ-propagation diagrams.

Velocity correlations of intermediate mass fragments (IMFs), produced in central collisions of Au+Au at 150 MeV beam energy, are extracted from measurements with the FOPI (phase I) detector system at SIS in GSI Darmstadt. The IMF correlation function for semicentral events is found to be affected by the directed sideward flow. When rotating the events into a unique reaction plane an enhancement of correlations, resulting from event mixing effects, vanishes. Selecting violent collisions with a high degree of azimuthal symmetry the correlation function appears nearly independent of additional event or single particle gate conditions. The comparison of the data with a Coulomb dominated final-state interaction model points to an expanding and multifragmenting soure with radius R∼14 fm.

It is shown that ‘‘superallowed’’ Gamow-Teller (GT) beta decays are possible for N=Z nuclei heavier than ${}_{28}{}^{56}{}_{}{}^{}\mathrm{Ni}_{28}^{}{}_{}{}^{}$, performing Hartree-Fock plus random phase approximation (Tamm-Dancoff approximation) calculations. Since Fermi-type beta decays are forbidden in N=Z even-even nuclei, it is pointed out that the main decay mode of the nuclei such as ${}_{50}{}^{100}{}_{}{}^{}\mathrm{Sn}_{50}^{}{}_{}{}^{}$ may be ‘‘superallowed’’ GT beta decay, which is a beta decay to the GT giant resonance state. The amplitude of isospin T=1 admixed to the T=0 ground state in N=Z nuclei is also calculated and discussed.