A direct experimental determination has been made of the ratio of the forward-angle positive-pion electroproduction cross section for a proton bound in the deuteron with that of a free proton for invariant masses of 1160 and 1232 MeV. A significant quenching of the reaction in the deuteron is observed.

Algebraic potentials from SO(3,1) and SO(3,2) representations of scattering functions are deduced by matching to scattering functions obtained by fitting ${}_{}{}^{12}{}_{}{}^{}\mathrm{-}_{}^{12}{}_{}{}^{}$C elastic-scattering differential cross sections. Their variations with energy suggest a simple mapping between algebriac and coordinate-space interactions.

Energy spectra of δ electrons emitted in coincidence with deep-inelastic heavy-ion collisions are calculated within a Langevin Monte Carlo description using the surface-friction model. We investigate the effects that wipe out the originally expected oscillatory pattern of the spectra. Emphasis is placed on the role of statistical fluctuations in extracting interaction time distributions of deep-inelastic collisions from the measured δ-electron spectra. The calculations are compared to data for U+Au at 8.65 MeV/nucleon.

A variational method is used to study the ground state of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. Expectation values are computed with a cluster expansion for the noncentral correlations in the wave function; the central correlations and exchanges are treated to all orders by Monte Carlo integration. The expansion has good convergence. Results are reported for the Argonne $v_{14}$ two-nucleon and Urbana VII three-nucleon potentials.

The depolarization parameter D in proton${\mathrm{-}}^{13}$C elastic scattering at 72 MeV has been measured with an accuracy of 0.003–0.004 per data point. D was found to deviate from unity by ∼0.02 around 65°, which is unambiguous evidence for a nucleon-nucleus spin-spin interaction. The data are well described by a microscopic calculation as well as by a phenomenological optical-model potential, which includes a real spherical spin-spin potential of strength $V_{\mathrm{ss}=0.7\mathrm{}\pm 0.1}$ MeV.

We have studied particle emission following ${\pi }^{+}$ absorption on ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ at $T_{\pi }$=150 MeV by using a large-solid-angle detector. We find an absorption cross section leading to two or more energetic protons in the final state to be 98±15 mb. We find that only about 65 mb can be explained as quasideuteron absorption.

In a model study, yrast band-crossing structures are shown to be qualitatively changed by residual neutron-proton interactions. This could explain some anomalies recently observed for light Kr isotopes. Large effects on the yrast-band g factors are predicted.

The proton-proton two-body density in the three-nucleon system is extracted from quasielastic-electron-scattering data. The two-body density is determined in momentum space using the integrated longitudinal response functions and assuming that the nonrelativistic Coulomb sum rule is valid. The range of the measurement is for momenta between 200 and 550 MeV/c. The data are compared to a proton-proton density calculated using Faddeev wave functions. The data and the calculation both show a ‘‘second maximum’’ but the data exceed the calculation by about an order of magnitude.

It has been known from some time that the intrinsic state labeled by the asymptotic quantum numbers ${(3/2\mathrm{}}^{+}$[631] lies quite close (<0.1 keV) to the ${(5/2\mathrm{}}^{+}$[633] ground state of ${}_{}{}^{229}{}_{}{}^{}\mathrm{Th}$. Using the energies of selected γ rays emitted following the α decay of ${}_{}{}^{233}{}_{}{}^{}\mathrm{U}$, we have obtained a value of 1±4 eV for the energy separation of these two intrinsic states.

We have measured np→d${\pi }^0$ cross sections at eleven beam energies within 16 MeV of threshold. Total cross sections are only 0.67±0.10 of the value which has been generally accepted for s-wave pion production strength near threshold. The differential cross sections are anisotropic at only 1 MeV (c.m.) above threshold. Our results are compared to ${\pi }^{+}$d→pp data and to predictions of two models.

Following theoretical predictions of competing prolate and oblate potential-energy minima, we present experimental evidence for the coexistence of prolate and oblate nuclear shapes which are associated in a given nucleus with the same single-quasiproton orbital. Prolate ΔI=2 and oblate ΔI=1 bands observed in the ${}_{}{}^{119}{}_{}{}^{}\mathrm{I}$ nucleus are proposed as built on an ${\mathrm{h}}_{11/2}$ proton with low K and high K, respectively.

Cross sections have been measured for the quasieleastic ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$(e,e’p) reaction in the missing-energy region beyond the t+d threshold, which is domianated by the ${(3/2\mathrm{}}^{+}$ resonance. The data are compared with distorted-wave impulse-approximation calculations, which involve nuclear overlap functions derived from a cluster-distortion model extended to the continuum. The measured recoil-momentum dependence of the ${(3/2\mathrm{}}^{+}$ resonance can only be reproduced if an anomalous longitudinal-transverse ratio is taken into account.

A study of magnetic dipole strength in the rare-earth region and application to the 148–160Gd isotopes has been carried out. Within the Nilsson model, all two-quasiparticle $K^{\pi }$${=1\mathrm{}}^{+}$ configurations have been constructed and the M1 strength distribution has been calculated. Information on the total summed (non-energy-weighted) M1 strength is obtained. The distribution of orbital and spin M1 strength over different energy regions and over the whole rare-earth mass region was studied. Relations to quadrupole ground-state deformation are pointed out.

We have measured the cross section for radiative capture of thermal neutrons on ${}_{}{}^3{}_{}{}^{}\mathrm{He}$. The measured cross section of 54±6 μb is used to estimate the astrophysical S factor for the reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}$(p,$e^{+}$ν${)}^4$He which gives rise to high-energy neutrinos from the Sun.

A numerical three-dimensional solution of the equations of relativistic hydrodynamics with Landau-type initial conditions has been obtained. Using an equation of state consistent with lattice-QCD calculations, the rapidity and transverse-momentum distributions are calculated for O+Au collisions at 200 GeV/nucleon. Satisfactory agreement with data is obtained with an initial temperature $T_i$=220 MeV corresponding to a mixed quark-gluon–hadron phase. A pure hadron phase is within this formalism inconsistent with the data.

High-spin states up to I${=31\mathrm{}}^{\mathrm{-}}$ have been studied in the ${}_{}{}^{218}{}_{}{}^{}\mathrm{Ra}$ nucleus and the staggering sequence of levels of positive and negative parity persists up to highest level. This observation supports the idea that in some nuclei the high-spin excitations may primarily be dominated by deformations which do not conserve the intrinsic parity (such as octupole, λ=3, and higher odd-λ multipolarities) rather than by the ‘‘usual’’ quadrupole (λ=2) and possibly higher even-λ multipolarities.

The widely used continuum discretized coupled-channels (CDCC) method for approximate calculations of three-body systems is discussed as a truncation of a Faddeev formulation in angular momentum space. A set of coupled equations is presented for converting a CDCC solution into a full solution of the original Schrödinger equation. A practical iterative procedure for solving the equations is outlined, based on the ‘‘distorted Faddeev equations’’ of Birse and Redish.

We have studied electron capture followed by delayed fission in ${}_{}{}^{234}{}_{}{}^{}\mathrm{Am}$. The half- life of ${}_{}{}^{234}{}_{}{}^{}\mathrm{Am}$ was determined to be 2.32±0.08 min and the measured ratio of delayed fissions to plutonium K x rays was (6.6±1.8)×${10}^{\mathrm{-}5}$. The observed fissions were unequivocally assigned to an electron-capture–delayed-fission process in americium by coincidence measurements between the K-capture x rays and the subsequent fission.

Emission patterns of neutrons from damped ${}_{}{}^{139}{}_{}{}^{}$La${+}^{40}$Ar reactions at $E_{\mathrm{lab}=400\mathrm{}}$ and 600 MeV, mostly consistent with sequential evaporation from accelerated fragments, reveal the existence of a high-energy component at all kinetic energy losses. The average multiplicity associated with this nonequilibrium component is found to scale with the radial kinetic energy at contact, with a threshold of $E_{\mathrm{rad}\mathrm{\approxeq }2}$ MeV/nucleon. Boltzmann-master-equation and Fermi-jet models disagree with the data, the latter model requiring enhanced high-momentum components.

A stochastic macroscopic approach to giant dipole resonances (GDR’s) in hot rotating nuclei is presented. In the adiabatic limit the theory reduces exactly to a previous adiabatic model where the unitary invariant metric is used to calculate equilibrium averages. Nonadiabatic effects cause changes in the GDR cross section and motional narrowing. Comparisons with experiments where deviations from the adiabatic limit are substantial are shown and can be used to determine the damping of the quadrupole motion at finite temperature.