We derive in-medium proton-proton cross sections in a microscopic model based upon the Bonn nucleon-nucleon potential and the Dirac-Brueckner approach for nuclear matter. We demonstrate the difference between proton-proton and neutron-proton cross sections and point out the need to distinguish carefully between the two cases. We also find substantial differences between our in-medium cross sections and phenomenological parametrizations that are commonly used in heavy-ion reactions.

High spin states in the nucleus ${}_{}{}^{91}{}_{}{}^{}\mathrm{Tc}$ have been studied via the fusion evaporation reaction ${}_{}{}^{58}{}_{}{}^{}\mathrm{Ni}$ ${(}^{36}$Ar, 3p) ${}_{}{}^{91}{}_{}{}^{}\mathrm{Tc}$, at 149 MeV and 140 MeV beam energy. The OSIRIS spectrometer, an additional high purity Ge detector at 162°, and several particle detectors were used to measure γγ- and particle-γγ coincidences, directional correlations of oriented states and line shapes due to Doppler-shift attenuation. Lifetimes in the ${10}^{\mathrm{-}12}$–${10}^{\mathrm{-}9}$ s range were measured by the recoil distance Doppler-shift method. Some 110 transitions were placed into a level scheme comprising 51 levels reaching up to 12.2 MeV excitation energy and a possible spin I=49/2ħ. A large number of spin-paritly assignments and E2/M1 mixing ratios and lifetimes were deduced. This extensive data set is used for a detailed test of shell model calculations. They were performed with different sets of parameters, within either 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 or an enlarged configuration space including the π(${\mathit{p}}_{3/2}$) and π(${\mathit{f}}_{5/2}$) orbits.

Pion-induced double charge exchange (${\mathrm{\pi }}^{+}$,${\mathrm{\pi }}^{\mathrm{-}}$) on a target of ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Se}$ has been investigated at a laboratory angle of 5° and incident kinetic energies of 132, 166, and 294 MeV. Cross sections (and limits) have been extracted for the various ground-state transitions. The double isobaric analog state and several other excited states are also observed.

Extremely high statistics γ-γ coincidence data for ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$ have been recorded following thermal neutron capture on ${}_{}{}^{167}{}_{}{}^{}\mathrm{Er}$. The results alter considerably recent experimental and theoretical work on ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$ and affect conclusions concerning the quality of the K quantum number in the neutron resonance region: earlier claims that K remains good and that this energy region is nonchaotic are shown to be based in part on band assignments that need to be seriously reexamined.

Vector and tensor analyzing powers (${\mathit{iT}}_{11}$, ${\mathit{T}}_{20}$, ${\mathit{T}}_{21}$, and ${\mathit{T}}_{22}$) for ${}_{}{}^6{}_{}{}^{}\to$${+}^{12}$C elastic scattering are presented for a ${}_{}{}^6{}_{}{}^{}\to$ bombarding energy of 30 MeV over the c.m. angular range 15°–138°. The results of optical model calculations made with central, spin-orbit, tensor and angular momentum dependent potential terms show that the large angle data for the vector and tensor analyzing powers are sensitive to the presence of a static spin-orbit term. The nonzero ${\mathit{T}}_{21}$ data show that a tensor potential must be included to describe ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ scattering.

We measured the first azimuthal distributions of triple-differential cross sections of neutrons emitted in heavy-ion collisions, and compared their maximum azimuthal anisotropy ratios with Boltzmann-Uehling-Uhlenbeck (BUU) calculations with a momentum-dependent interaction. By restricting the analysis to free neutrons, the BUU calculations of the triple-differential cross sections for positive rapidity neutrons emitted at polar angles from 7° to 27° agree generally with the data; however, the polar-angle dependence of the maximum azimuthal anisotropy ratio for these free neutrons is insensitive to the size of the nuclear incompressibility modulus K characterizing the nuclear matter equation of state.

First results of rigorous 3N Faddeev calculations including realistic NN and 3N forces (3NF) are presented. We compare the theoretical analyzing power ${\mathit{A}}_{\mathit{y}}$ in elastic Nd scattering at ${\mathit{E}}_{\mathrm{lab}}^{\mathit{N}}$=3.0 MeV to recently measured nd data. As 3NF we take the Tucson-Melbourne 2π-exchange model. We study its dependence on the πN form-factor cutoff parameter and also the interplay of three realistic NN forces with that 3NF. The discrepancy between theory and experiment, present for NN forces only, turns out to be aggravated when including that 3NF. Further efforts to be taken are indicated.

The influence of short-range correlations on the p-wave single-particle spectral function in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ is studied as a function of energy. This influence, which is represented by the admixture of high-momentum components, is found to be small in the p-shell quasihole wave functions. It is therefore unlikely that studies of quasihole momentum distributions using the (e,e’p) reaction will reveal a significant contribution of high-momentum components. Instead, high-momentum components become increasingly more dominant at higher excitation energy. The above observations are consistent with the energy distribution of high-momentum components in nuclear matter.

Electromagnetic fission cross sections of a 120 MeV/nucleon ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ beam incident on five targets, ${}_{}{}^9{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Cu}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Ag}$, and ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{U}$, have been extracted from measurements of projectile velocity fission fragments. The nuclear interaction contributions to the experimentally observed cross sections were determined by extrapolation from the Be target data using a geometrical scaling model and by an empirical decomposition of the fission charge distributions. The results are compared to model calculations in which electric quadrupole excitations have been included.

In this paper we give explicit formulae in momentum and coordinate space for the three-nucleon potentials due to ρ and π meson exchange, derived from off-mass-shell meson-nucleon scattering amplitudes which are constrained by the symmetries of QCD and by the experimental data. Those potentials have already been applied to nuclear matter calculations. Here we display additional terms which appear to be the most important for nuclear structure. The potentials are decomposed in a way that separates the contributions of different physical mechanisms involved in the meson-nucleon amplitudes. The same type of decomposition is presented for the π-π Tucson-Melbourne force: the Δ isobar, the chiral symmetry breaking, and the nucleon pair terms are isolated.

Faddeev equations for the coupled ΛNN and ΣNN systems are solved precisely for meson-theoretical nucleon-nucleon and hyperon-nucleon interactions. In this force model the hypertriton is not bound.

Effects of polarization and alignment of the deuteron on the polarization and cross section of the outgoing nucleons in deuteron photodisintegration have been investigated for low- and medium-energy gamma rays. Meson exchange currents and relativistic effects are included and the numerical calculations for the Paris potential are carried out. A comparison with the published results of Arenhövel and Schmitt is made.

The ${\mathit{T}}_{\mathit{z}}$=-3/2, A=4n+1 nuclide ${}_{}{}^{73}{}_{}{}^{}\mathrm{Sr}$ produced in the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${(}^{36}$Ar,3n) reaction has been observed via beta-delayed proton emission. A single proton group at a laboratory energy of 3.75±0.04 MeV has been observed, corresponding to decay of the T=3/2 isobaric analog state in ${}_{}{}^{73}{}_{}{}^{}\mathrm{Rb}$ to the ground state of ${}_{}{}^{72}{}_{}{}^{}\mathrm{Kr}$. Combining this measurement with a Coulomb displacement energy calculation yields a mass excess for ${}_{}{}^{73}{}_{}{}^{}\mathrm{Sr}$ of -31.82±0.24 MeV based on a predicted mass for ${}_{}{}^{72}{}_{}{}^{}\mathrm{Kr}$ of -53.94±0.24 MeV.

The main goal of this work is to establish the nuclear decay scheme of ${}_{}{}^{76}{}_{}{}^{}\mathrm{Sr}$ and energy levels of its doubly odd daughter nucleus ${}_{}{}^{76}{}_{}{}^{}\mathrm{Rb}$. The extremely neutron deficient nucleus ${}_{}{}^{76}{}_{}{}^{}\mathrm{Sr}$ lying at the N=Z (=38) line with half-life of 8.9 s was produced in spallation reactions of 600 MeV protons from the CERN Synchrocyclotron (SC) with a Nb multifoil target in conjunction with a W surface ionization source at the ISOLDE facility. The γ-spectroscopy measurements have been performed with two Ge detectors which were positioned at about ±30° respectively downstream to the ${}_{}{}^{76}{}_{}{}^{}\mathrm{Sr}$ beam. The obtained singles and coincidence γ spectra were used to determine energies and intensities of γ lines assigned to the decay of ${}_{}{}^{76}{}_{}{}^{}\mathrm{Sr}$ and to establish some details of the nuclear level configuration of its daughter nucleus ${}_{}{}^{76}{}_{}{}^{}\mathrm{Rb}$ up to 1000 keV.

The firm determination of spins and parities of possible octupole states at excitation energies between 2 and 3 MeV is crucial for understanding the anomaly in the behavior of low-energy octupole states which occurs in the Pt-Hg region. The ${}_{}{}^{196}{}_{}{}^{}\mathrm{Pt}$(n,n’γ) reaction has been used in an effort to identify four possible octupole states observed previously in the (p,p’) reaction and to make spin-parity assigments.

Considerable data have recently been collected on light zirconium isotopes. We present new measurements on ${}_{}{}^{84}{}_{}{}^{}\mathrm{Zr}$ and some unpublished results on ${}_{}{}^{82}{}_{}{}^{}\mathrm{Zr}$. We have performed calculations on ${}_{}{}^{82,84,86}{}_{}{}^{}\mathrm{Zr}$ using an extension to the IBM which allows a collective core to couple to up to four unpaired fermions (two broken pairs). The role of vibrational collectivity is clear in the N=44 and N=46 nuclei, but collective rotation becomes the dominant mode below N=44. The relative positions of the neutron and proton Fermi surfaces are crucial in determining the complexity of the decay path down the yrast states, being dominated by proton configurations for N≤44 but showing strong competition between neutron and proton structures when N>44.

The formation cross sections of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ from Al, Fe, Co, Ni, Cu, Zn, Ag, and Au targets irradiated with 12 GeV protons were measured by accelerator mass spectrometry. The obtained cross sections were consistent with the excitation functions predicted from the literature values measured at other proton energies within the experimental uncertainties. The ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ cross sections increased with an increase in the target mass. On the other hand, the ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ cross sections decreased from Al to Ag targets, but increased somewhat from Ag to Au. The formation mechanisms of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ including ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$, and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ are discussed with respect to fitting of the experimental results to the calculated values using the universal formula of Campi et al. During the course of the discussion, we introduce a new parameter, the degree of neuton excess (N-Z)/A, in order to classify light fragments more clearly.

It is found that the production of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ with positive values for the degree of neutron excess can be well reproduced by the formula, indicating that fragmentation is a dominant process for ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ production from Fe to Au targets and for ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ from Ag to Au. However, the values calculated by the formula overestimate the yields of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$, and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ with negative values or zero for the neutron-excess parameter. Through a comparison of the calculated and experimental data it is also found that the cross section ratios of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$${/}^7$Be, ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$${/}^{26}$Al, and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$${/}^{22}$Na are linearly correlated with the degree of neutron excess of the targets. This suggests that the production of ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{22}{}_{}{}^{}\mathrm{Na}$, and ${}_{}{}^{26}{}_{}{}^{}\mathrm{Al}$ with negative or zero (N-Z)/A by a fragmentation process from Ag to Au targets is suppressed relative to those of ${}_{}{}^{10}{}_{}{}^{}\mathrm{Be}$ and ${}_{}{}^{24}{}_{}{}^{}\mathrm{Na}$ with positive values of the neutron-excess parameter.

The widths of the 3089 keV and the 3684 keV levels in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ are precisely measured using nuclear self-absorption and employing amorphous ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ absorbers and scatterers. The role of the effective temperature of carbon is discussed in some detail. The result for the 3089 keV level was found to be larger by about 25% than the compiled value.