1/$N_c$ expansion in QCD (with ${\mathit{N}}_{\mathit{c}}$ the number of colors) suggests using a potential from meson sector (e.g., Richardson) for baryons. For light quarks a σ field has to be introduced to ensure chiral symmetry breaking (χSB). It is found that nuclear matter properties can be used to pin down the χSB modeling. All masses, ${\mathit{M}}_{\mathit{N}}$, ${\mathit{m}}_{\mathrm{\sigma }}$, ${\mathit{m}}_{\mathrm{\omega }}$, are found to scale with density. The equations are solved self-consistently.

Parity nonconservation has been studied in the transmission of longitudinally polarized epithermal neutrons incident upon a ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ target. Previous experiments have demonstrated the existence of a large value of the longitudinal asymmetry in the 0.734-eV p-wave resonance of the compound nucleus ${}_{}{}^{140}{}_{}{}^{}\mathrm{La}$, but report conflicting values for the measured asymmetry. We report the results of an experiment at the Los Alamos Neutron Scattering Center (LANSCE) which measured the asymmetry by two independent methods. One of these methods utilizes a conventional polarizer and a single lanthanum target. The other method uses an unpolarized beam with two lanthanum targets, and therefore does not require a separate measurement of the beam polarization. The asymmetry values determined from these two methods (0.1015±0.0045 and 0.0955±0.0035, respectively) are compared to previously measured values. Measurement of the asymmetry of the 0.734-eV resonance in ${}_{}{}^{139}{}_{}{}^{}\mathrm{La}$ provides a highly accurate method of determining the polarization of an epithermal neutron beam.

Coulomb dissociation of light nuclear projectiles in the electric field of heavy target nuclei has been experimentally investigated as an alternative access to radiative capture cross sections at low relative energies of the fragments, which are of astrophysical interest. As a pilot experiment the breakup of 156 MeV ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ projectiles at ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ with small emission angles of the α particle and deuteron fragments has been studied. Both fragments were coincidentally detected in the focal plane of a magnetic spectrograph at several reaction angles well below the grazing angle and with relative angles between the fragments of 0°–2°. The experimental cross sections have been analyzed on the basis of the Coulomb breakup theory. The results for the resonant breakup give evidence for the strong dominance of the Coulomb dissociation mechanism and the absence of nuclear distortions, while the cross section for the nonresonant breakup follows theoretical predictions of the astrophysical S factor and extrapolations of corresponding radiative capture reaction cross section to very low c.m. energies of the α particle and deuteron. Various implications of the approach are discussed.

The double isobaric analog state ‖IAS⊗⊗IAS〉 and a new resonance below the ‖IAS⊗IAS〉 have been observed in pion-induced double-charge-exchange reactions on ${}_{}{}^{93}{}_{}{}^{}\mathrm{Nb}$. Angular distributions have been measured for both transitions. The cross section observed in the ${\mathit{T}}_{<}$ resonance is 21% of that for the ‖IAS⊗IAS〉 in ${}_{}{}^{93}{}_{}{}^{}\mathrm{Tc}$. We mention various possibilities for the nature of the observed resonance but have no unique explanation for its large cross section.

Lifetimes of some excited nuclear levels in the subnanosecond region are determined from delayed coincidence measurements. The measured values of half-life pertain to the nuclear levels: 161 keV of ${}_{}{}^{133}{}_{}{}^{}\mathrm{Cs}$ (180±10 psec), 343 keV of ${}_{}{}^{175}{}_{}{}^{}\mathrm{Lu}$ (281±10 psec), 113 keV of ${}_{}{}^{177}{}_{}{}^{}\mathrm{Hf}$ (583±6 psec), 896 keV of ${}_{}{}^{168}{}_{}{}^{}\mathrm{Er}$ (≤120 psec), 724 and 757 keV of ${}_{}{}^{95}{}_{}{}^{}\mathrm{Nb}$ (≤70 psec each). Measurements on the 896 ${(}^{168}$Er), 724 and 757 keV ${(}^{95}$Nb) levels have not been reported earlier. The magnetic moment of the 113 keV level of ${}_{}{}^{177}{}_{}{}^{}\mathrm{Hf}$ has been recalculated using the measured lifetime and a new value of μ(9/$2^{\mathrm{-}}$)=(0.91±0.02)${\mathrm{\mu }}_{\mathit{N}}$ is found which is in better agreement with the value predicted from theoretical considerations.

Proton 4p-4h intruder excitations can be formed in even-even nuclei with a large neutron excess. The excitation energy and the systematics of such 4p-4h intruder excitations is discussed for the even-even Sn and Pb nuclei.

The Coulomb dissociation cross section for ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$ on ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ is calculated for different models of the distribution of dipole response strength in ${}_{}{}^{11}{}_{}{}^{}\mathrm{Li}$. All the available models fail in accounting for the low energy behavior of the cross section.

The isotriplet neutron-proton pair in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ is found to contribute very little to the cross-section and spin observables in positive pion absorption at low energies.

The dynamics of a split nucleus is simulated within a semiclassical description based on the Landau-Vlasov equation with a Uehling-Uhlenbeck collision term. Initially, the spherical system is suddenly divided into two equal parts boosted in opposite directions perpendicularly to the separation plane. The role of nucleon-nucleon collisions is studied in the damping of the collective energy and of deformations. The dynamic barrier profiles and heights are also strongly dependent on these two-body effects and may be compared with those of the liquid-drop model applied to excited systems.

The relativistic derivative scalar coupling model of Zimanyi and Moszkowski, which is based on the original σ-ω model, is investigated both for infinite symmetric nuclear matter and finite spherical nuclei. We find that while this model yields satisfactory compressibility in nuclear matter, and consequently gives good total binding energies for finite nuclei, it however fails to give the right spin-orbit interaction in finite nuclei. Calculated results are shown for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and compared to the σ-ω model and experimental data; the origin of the discrepancy is discussed.

A semiclassical method has been used to calculate terms of order ${\mathrm{ħ}}^2$, the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{16}$O elastic-scattering cross section for the c.m. energy range 35–90 MeV for various optical model potentials. We find that the calculated results with an energy-dependent absorptive part along with an angular momentum cutoff agree qualitatively with the experimental results.

The corrections made in a recent paper to the published values for double K-shell ionization in the electron capture decays of ${}_{}{}^{54}{}_{}{}^{}\mathrm{Mn}$ and ${}_{}{}^{65}{}_{}{}^{}\mathrm{Zn}$ are not applicable to the data from which these values were derived. Attention is called to a recent article that is relevant to the topic of the paper.

We compare a phenomenology of ${\mathrm{\pi }}^0$ production in p-p scattering with recent Indiana University Cyclotron Facility data for energies near threshold. The computed magnitude of the cross section is too small by a factor of about 5, even though the energy dependence is satisfactorily described.

The 1/2[530] decoupled band in ${}_{}{}^{229}{}_{}{}^{}\mathrm{Pa}$ has been identified up to the 19/$2^{\mathrm{-}}$ level in (p,t) and (p,2nγ) experiments. It is found that the 3/$2^{\mathrm{-}}$ band head has an excitation energy of 19(10) keV, and can thus not be identified with a 123 keV level observed in the ${}_{}{}^{229}{}_{}{}^{}\mathrm{U}$ electron capture decay. This removes the evidence presented earlier for a spin-parity assignment of 5/$2^{+\mathrm{-}}$5/$2^{\mathrm{-}}$ to a proposed nearly degenerate ground-state doublet in ${}_{}{}^{229}{}_{}{}^{}\mathrm{Pa}$.

Parity doublet bands with K=$0^{\pm }$ implying reflection asymmetry (with an average spacing between the levels of the same spin and opposite parity of 12.6 keV) are observed in ${}_{}{}^{224}{}_{}{}^{}\mathrm{Ac}$. In the strong coupling limit all K=$0^{\pm }$ parity doublet bands are shown to be constrained to Newby splittings with the same absolute magnitude, but with opposite sign. Experimentally, the Newby splittings in ${}_{}{}^{224}{}_{}{}^{}\mathrm{Ac}$ approach this theoretical expectation.

The second-order corrections to the Kerman-McManus-Thaler optical potential for the elastic scattering of protons from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ are calculated at 135, 200, and 300 MeV incident energies, paying particular attention to the nonlocalities inherent in the potential. It is shown that these effects result in a significant reduction in the proton-target absorption.

We present an exciton model for preequilibrium emission in nucleon-induced reactions in which linear-momentum conservation is included. The particle emission contributions from the first two preequilibrium stages are calculated by determining exact particle-hole state densities with a specific energy and linear momentum in a Fermi-gas model of the nucleus. Angular distributions arise naturally from our treatment and do not have to be added in an ad hoc way. The angular distributions that we obtain from the first two preequilibrium stages are identical to those found using the Kikuchi-Kawai quasifree scattering kernel.