Double differential and total cross sections of the (${\mathrm{\pi }}^{\mathrm{-}}$,pd), (${\mathrm{\pi }}^{\mathrm{-}}$,dp), and (${\mathrm{\pi }}^{\mathrm{-}}$,dd) reactions on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ were measured over a wide angular range at an incident pion kinetic energy of 165 MeV. The shape of the angular distributions of the differential cross sections of these reactions is in most cases similar to that of the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${\mathrm{\pi }}^{\mathrm{-}}$,pp)X reaction. These similarities seem to indicate a pickup mechanism in certain regions of phase space following three-nucleon absorption. Contributions from both three-nucleon absorption and two-step processes are found to be important for the above type of reactions.

Angular correlation measurements have been performed for the heavy-ion inelastic channel ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${(}^{16}$O${,}^{16}$O${)}^{16}$O($3^{\mathrm{-}}$, 6.13 MeV) over a wide energy range. The spin alignment was determined and the range of acceptable values of J has been narrowed down for several structures in the excitation function. Our results rule out the possibility of any correlation between the structures in this channel and those in the elastic and the 6.05 MeV ($0_2^{+}$) inelastic channel and are in conflict with an interpretation in terms of the band crossing model.

The present paper is based on a suggestion by Franco and Yin that the phase of the nucleon-nucleon scattering amplitude should vary with momentum transfer. Studying proton${\mathrm{-}}^4$He elastic scattering at 1 GeV, we found this phase to be actually important for the description of spin observables. In particular the spin rotation parameter Q is sensitive to its sign.

A study of the systematics of B(E3;$0_1^{+}$→$3_1^{\mathrm{-}}$) values for nuclei throughout the Periodic Table shows clear enhancements at certain neutron numbers. These neutron numbers are in remarkably good agreement with those predicted by Strutinsky-type calculations to be likely candidates for static octupole deformation. The comparison with predicted proton numbers is more ambiguous.

Dielectron production in proton-nucleus reactions is studied in the cascade model. In addition to production from the proton-neutron bremsstrahlung and the decay of delta, we have also taken into account the contribution from the pion-nucleon interaction. The calculated dielectron invariant mass spectra are compared to the data obtained recently for proton-Be reactions at incident energies of 1.05, 2.1, and 4.9 GeV.

Velocity distributions of mass-identified evaporation residues produced in the ${}_{}{}^{28}{}_{}{}^{}\mathrm{t}$/rSi${+}^{28}$Si reaction have been measured at bombarding energies of 174, 215, 240, 309, 397, and 452 MeV using time-of-flight techniques. These distributions were used to identify evaporation residues and to separate the complete-fusion and incomplete-fusion components. Angular distributions and total cross sections were extracted at all six bombarding energies. The complete-fusion evaporation-residue cross sections and the deduced critical angular momenta are compared with lower energy data and the predictions of existing models.

Calculations for ${}_{}{}^{154}{}_{}{}^{}\mathrm{Sm}$${+}^{154}$Sm collisions that account for the deformed surfaces indicate that the threshold for nuclear reactions is about 50 MeV below the nominal Coulomb barrier. Some specific features of such low-energy collisions are discussed.

Elastic scattering angular distributions of ${}_{}{}^{32,36}{}_{}{}^{}\mathrm{S}$ (beams)${+}^{58.64}$Ni have been measured at several energies around the Coulomb barrier. An optical-model analysis of the data reveals remarkable energy dependences of the potentials at the strong absorption radii, in all cases. The largest effects are observed for ${}_{}{}^{32}{}_{}{}^{}\mathrm{r}$/rS${+}^{64}$Ni. This is due to the coupled reaction channels which also strongly influence the sub-barrier fusion cross sections. Coupled-channels calculations of elastic scattering and fusion have been performed, including the inelastic excitations of projectile and target; the need for considering additional (transfer) channels is made evident. We also have indications that sub-barrier fusion is not merely tunneling through a potential barrier, although energy dependent, as absorption into fusion takes place at larger internuclear distances. Older fusion and quasielastic transfer data are overviewed and compared with the reaction cross sections extracted from elastic scattering. Open questions still remain about the role of specific channels in determining the observed isotopic differences.

We derive an analytical expression for the essential parameters (viz., positions, heights, and curvatures) characterizing the extrema of the effective potential between two heavy ions. These parameters together with the energy are used to calculate, in closed form, the times for complete fusion above the Coulomb barrier. The method is found to work well for nuclear (and/or Coulomb) trajectories of zero or small orbital angular momentum when friction is absent. The inclusion of dissipation is shown to reduce the fusion time substantially for typical heavy-ion systems provided the energy satisfies certain kinematic constraints.

We have directly measured, for the first time, the neutron-fission branching ratio, ${\mathrm{\Gamma }}_{\mathit{n}}$/${\mathrm{\Gamma }}_{\mathit{f}}$, of an actinide nucleus ${(}^{238}$U) excited in inelastic scattering as a function of excitation energy. This was accomplished using a ≊4π array of fission counters to separate fission neutrons from decay neutrons in the simultaneous coincidence experiments (α,α’f) and (α,α’nf¯). The measured branching ratio agrees well with previous photoneutron data. In a separate experiment, we have measured the angular distribution of alpha particles scattered from ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ in coincidence with fission decay (α,α’f). This provides us with an estimate of the cross section (in the fission channel) for exciting the isosca- lar giant monopole and giant quadrupole resonances. This estimate, combined with the ${\mathrm{\Gamma }}_{\mathit{n}}$/${\mathrm{\Gamma }}_{\mathit{f}}$ measurement, allows us to place bounds on the neutron-fission branching ratio for the isoscalar giant monopole and giant quadrupole resonances themselves.

We have measured the number of prefission and postfission neutrons emitted in the fission of ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ targets bombarded with 475 MeV protons as a function of the total kinetic energy of the two fission fragments, the fission fragment mass, and the recoil velocity of the excited nucleus prior to fission. The average number of prefission neutrons is approximately equal to the average number of postfission neutrons for both targets and the total number equals ∼17. The number of prefission neutrons increases with increasing recoil velocity and their average number is substantially larger than that predicted by the Bohr-Wheeler theory.

A search for radiative transitions between 0.100 and 0.9 MeV from the p-shell hypernucleus ${}_{\mathrm{\Lambda }}{}^{10}{}_{}{}^{}\mathrm{B}$ was undertaken. Of special interest are the M1 spin-flip transitions between members of the doublet formed by coupling an s-shell Λ hyperon to the nuclear core. No such transitions were observed in this energy range attributable to ${}_{\mathrm{\Lambda }}{}^{10}{}_{}{}^{}\mathrm{B}$. This negative result provides additional constraints on the parameters of the p-shell Λ-nucleon effective potential. Evidence is presented of the observation of a γ ray which may be attributed to either the hyperfragment ${}_{\mathrm{\Lambda }}{}^8{}_{}{}^{}\mathrm{Li}$ or ${}_{\mathrm{\Lambda }}{}^8{}_{}{}^{}\mathrm{Be}$. A cross section for the exclusive reaction ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$(π,π’${)}^7$o/r${\mathit{Li}}^{\mathrm{*}}$ (${\mathit{E}}_{\mathit{x}}$=478 keV) of 2.2±0.3 mb/sr was also obtained.

Elastic scattering of positive and negative pions by nuclei has been analyzed by means of Glauber theory. The full multiple scattering series is calculated, including effects of the Coulomb interaction and inner Coulomb corrections. Double and quadruple charge exchange contributions to the elastic scattering differential cross sections are also included. Applications are made to scattering by ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. Comparisons are made with measurements at 674 MeV.

The energy dependence of the cross sections for the first $2^{+}$, $3^{\mathrm{-}}$, and $4^{+}$ excitations in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ from pion inelastic scattering at incident pion energies from ${\mathit{T}}_{\mathrm{\pi }}$=116 to 291 MeV is investigated. A significant signature of Coulomb-nuclear interference is observed in the ${\mathrm{\pi }}^{\mathrm{-}}$/${\mathrm{\pi }}^{+}$ cross-section ratio.

Double differential cross sections for inelastic electron scattering from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ have been measured at bombarding energies between 279 and 725 MeV. The longitudinal and transverse response functions were obtained for constant momentum transfer between 300 and 500 MeV/c. Plane-wave impulse approximation calculations overestimate the longitudinal response and produce fair agreement with the transverse part. The Coulomb sum is determined and compared with exact calculations. Within the experimental error the data exhaust the sum rule; this provides a first measurement of ground-state correlations.

A general separable NN interaction model containing all possible couplings to NΔ and ΔΔ channels is developed and used to describe elastic and inelastic two-nucleon scattering up to 1 GeV. We start out from the separable Graz-II potential for the elastic NN interaction and extend it to include inelastic channels. Quantitative fits to the phenomenological phase parameters in the ${}_{}{}^1{}_{}{}^{}$${\mathit{D}}_2$ and ${}_{}{}^3{}_{}{}^{}$${\mathit{F}}_3$ NN states are obtained between 0 and 1000 MeV. The resulting separable potentials are of low rank and therefore very convenient for applications to few-body calculations.

The contribution of the nucleonic component to deep inelastic lepton scattering off ${}_{}{}^2{}_{}{}^{}\mathrm{H}$, ${}_{}{}^3{}_{}{}^{}\mathrm{H}$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, and ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ nuclei is analyzed in terms of momentum distributions and spectral functions obtained from few-body calculations which employ realistic nucleon-nucleon interactions. The nuclear structure function is evaluated within the framework of the convolution model taking relativistic effects into account by means of the flux factor. A comparison with previous calculations performed with a nonrelativistic normalization of the spectral function and using, in the case of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, an independent particle model, is presented. It is shown that short-range and tensor correlations resulting from realistic nucleon-nucleon interactions strongly increase the nucleon mean removal and kinetic energies and, consequently, enhance the calculated European Muon Collaboration effect in the direction suggested by the experimental data in the region 0.2≤x≤0.7; for x≤0.2 and x≥0.7, an appreciable discrepancy between theory and experiment still persists and the difficulties in giving an interpretation of the effect in the whole range of x, in terms of nucleonic degrees of freedom only, are pointed out. The role of ${\mathit{Q}}^2$ rescaling is analyzed; it is found that present experimental data seem to require only a small increase of the quark confinement size for a nucleon imbedded in the nuclear medium. The nuclear structure function for three-nucleon systems is calculated in the region x>1, where it is shown to be very sensitive to the correlation structure of the nucleon spectral function.

A recently developed technique for fast timing measurements using β-γ-γ coincidences with plastic, ${\mathrm{BaF}}_2$ and Ge detectors, respectively, has been used to measure lifetimes in the range 5–1500 ps in the neutron-rich nuclei ${}_{}{}^{97}{}_{}{}^{}\mathrm{Sr}$, ${}_{}{}^{97}{}_{}{}^{}\mathrm{Y}$, and ${}_{}{}^{97}{}_{}{}^{}\mathrm{Zr}$. The results for ${}_{}{}^{97}{}_{}{}^{}\mathrm{Y}$ are interpreted in terms of quadrupole vibrational excitations. For ${}_{}{}^{97}{}_{}{}^{}\mathrm{Sr}$ the experimental data suggest the coexistence of spherical/vibrational and deformed states and allow the extraction of mixing matrix elements between them. A quadrupole moment of ‖${\mathit{Q}}_0$‖=3.5(4) e b for the deformed states in ${}_{}{}^{97}{}_{}{}^{}\mathrm{Sr}$ has been deduced.

With the use of mass-separated sources, the β-decay properties of ${}_{}{}^{151}{}_{}{}^{}\mathrm{Yb}$ and ${}_{}{}^{151}{}_{}{}^{}\mathrm{Tm}$ were investigated. The ${\mathit{h}}_{11/2}$, ${\mathit{s}}_{1/2}$, ${\mathit{d}}_{3/2}$, ${\mathit{d}}_{5/2}$, and ${\mathit{g}}_{7/2}$ single-proton states in ${}_{}{}^{151}{}_{}{}^{}\mathrm{Tm}$ and the ${\mathit{f}}_{7/2}$, ${\mathit{h}}_{9/2}$, ${\mathit{p}}_{3/2}$, ${\mathit{i}}_{13/2}$, and probably the ${\mathit{p}}_{1/2}$ single-neutron states in ${}_{}{}^{151}{}_{}{}^{}\mathrm{Er}$ were identified. Systematics of neutron states in even-Z N=83 isotones are compared with predictions of spherical Hartree-Fock-Bogoliubov calculations.

Half-lives of 47(6) ps in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Y}$ and 72(7) ps in ${}_{}{}^{100}{}_{}{}^{}\mathrm{Y}$, measured by β-γ-γ coincidences, and intraband M1/E2 ratios give M1 strengths and g factors of the bands π(5/2[422] in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Y}$, ν(3/2[411] in ${}_{}{}^{99}{}_{}{}^{}\mathrm{Sr}$, and π(5/2[422]ν 3) / 2 [411] in ${}_{}{}^{100}{}_{}{}^{}\mathrm{Y}$. The results are in remarkable agreement with the simple picture of these nuclei as a deformed ${}_{}{}^{98}{}_{}{}^{}\mathrm{Sr}$ core plus one or two valence nucleons, thus indicating that the deformation saturates for A≃100 Sr and Y nuclei. This ‘‘early’’ saturation can be explained in terms of valence Nilsson orbitals.