Fission fragment angular distributions have been measured in reactions of ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{208}$Pb, ${}_{}{}^{232}{}_{}{}^{}\mathrm{Th}$, ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$, ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$; ${}_{}{}^{19}{}_{}{}^{}$F${+\mathrm{}}^{208}$Pb; ${}_{}{}^{24}{}_{}{}^{}$Mg${+\mathrm{}}^{208}$Pb; ${}_{}{}^{28}{}_{}{}^{}$Si${+\mathrm{}}^{208}$Pb; ${}_{}{}^{32}{}_{}{}^{}$S${+\mathrm{}}^{197}$Au; and ${}_{}{}^{32}{}_{}{}^{}$S${+\mathrm{}}^{208}$Pb at several bombarding energies. The data are analyzed within the standard theory and it is found that the angular anisotropies for reactions with ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and heavier projectiles are significantly larger than expected theoretically. Comparative studies of reactions in which different target-projectile combinations are leading to similar fissioning systems show that the large angular anisotropies are associated with the charge (and mass) of the projectile. This excludes large angular momenta and temperatures as the cause of these discrepancies. It is concluded that the onset of the quasifission reaction is responsible for the large observed anisotropies.

Angular correlations of fragments both in and out of the reaction plane from 292-MeV ${}_{}{}^{20}{}_{}{}^{}\mathrm{induced}$ fission of ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$, ${}_{}{}^{181}{}_{}{}^{}\mathrm{Ta}$, ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$, ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$, and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ have been measured. The correlated data have been evaluated in terms of a full linear momentum transfer component and less than full linear momentum components. The method of evaluation has also been applied to other available data for ${}_{}{}^{16}{}_{}{}^{}\mathrm{-}$ and ${}_{}{}^{20}{}_{}{}^{}\mathrm{induced}$ reactions. The maximum angular momentum $l_{\mathrm{FLMT}}$ associated with full linear momentum transfer for the systems analyzed agrees with the predictions of a classical dynamical model based on the proximity nuclear potential and one-body nuclear friction. Because of projectile breakup, the angular momentum distribution in the composite nucleus is markedly distorted from the (2l+1) distribution expected for full linear momentum transfer.

We present a simple parametrization of the S-, P-, and D-wave π-N amplitudes using separable potentials for $T_{\pi }$<1 GeV. The effect of the inelasticity is included in the Green’s function while maintaining consistency with unitarity. The $P_{11}$ amplitude is written as a pole plus nonpole in order to describe pion absorption in A≥2.

The use of alternative representations of spin observables for elastic scattering is investigated within the context of comparing relativistic and nonrelativistic approaches. The results of calculations of the observables $A_y$ and Q together with the alternatives S and β are presented for elastic scattering of 650, 500, and 318 MeV protons from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. At the lower energy, the spin observables S and β appear to be particularly sensitive to the nature of the theoretical treatment. The implications of theoretical input uncertainties for the possibility of extracting nuclear target information in the relativistic approach are considered.

Using a liquid deuterium target, 800 MeV quasielastic parrow+p and parrow+n spin-rotation and -depolarization parameters ($D_{\mathrm{SS}}$,$D_{\mathrm{SL}}$,$D_{\mathrm{LS}}$,$D_{\mathrm{LL}}$,$D_{\mathrm{NN}}$ ) were determined over the center-of-momentum angular range 14.3°–69.2°. The parrow+p results are in good agreement with existing elastic results and predictions from phase shift analysis. The parrow+n results, in general, are not in agreement with predictions from phase shift solutions. Small corrections to previously reported parrow+p elastic observables are also discussed.

We present calculations of the longitudinal and transverse response functions for (e,e’) inclusive reactions on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. The calculations are made in the impulse approximation and use the medium-modified electromagnetic form factors of the nucleon which we calculated recently. Most of our calculations were made using a Fermi-gas model, however, we also present results for calculations which make use of wave functions of a finite-nucleus model. (In the latter case we include the medium-modified form factors in a local-density approximation.) One finds a very good fit to the longitudinal response using the medium-modified form factors. The fit to the transverse response is less satisfactory and indicates the presence of a significant amplitude in the response which is not described by the quasielastic nucleon-knockout mechanism. The fit of the longitudinal response achieved here suggests that the nucleon form factor is modified in the medium. These calculations support similar conclusions we have drawn from our study of the longitudinal response functions of ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$.

The energy dependence of the total angle-integrated cross section for the production of astatine isotopes from (p,${\pi }^{\mathrm{-}}$xn) double charge exchange reactions on bismuth ${(}^{209}$Bi) was measured from 120 to 800 MeV using activation and radiochemical techniques. Chemical yields were estimated by direct radioassaying of ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ activity in thin (∼1 mg/${\mathrm{cm}}^2$), irradiated bismuth targets. Calculations of the contributions of secondary (two-step) reactions to these measured astatine yields were performed, based partially upon the observed ${}_{}{}^{211}{}_{}{}^{}\mathrm{At}$ activity although even at the highest energies, the contribution to products lighter than ${}_{}{}^{207}{}_{}{}^{}\mathrm{At}$ was negligible. These data for products with as many as seven neutrons removed from the doubly coherent product ${(}^{210}$At) display nearly Gaussian shapes for the mass distributions of the astatine residues, with the maximum occurring for about ${}_{}{}^{204}{}_{}{}^{}\mathrm{At}$. The most probable momentum transfer deduced from these distributions for the initial ${\pi }^{\mathrm{-}}$ production step was 335 MeV/c. The observed excitation functions display a behavior similar to that observed for the yield of ${}_{}{}^{210}{}_{}{}^{}\mathrm{Po}$ from a (p,${\pi }^0$) reaction on ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$, but radically different from that observed for inclusive ${\pi }^{\mathrm{-}}$ reactions on a heavy nucleus. These data are discussed in terms of recent theoretical approaches to negative pion production from bismuth. In addition, a simple, schematic model is developed to treat the rapidly decreasing percentage of the total inclusive ${\pi }^{\mathrm{-}}$ emission which is observed for this double charge exchange reaction. This model reflects the opacity of a nucleus to a source of internal energetic protons.

We have estimated the contribution of relativistic effects to the neutron-deuteron scattering lengths by solving the nonrelativistic and relativistic Faddeev equations for several local and nonlocal potentials that act only in S waves. We found that the relativistic effects increase the quartet scattering length by about 0.2 fm and decrease the doublet scattering length by roughly the same amount. These effects are not small in the case of the doublet scattering length, where they represent a correction of more than 20% of the experimental value.

Basic features of proton-nucleus optical potentials for use in the Dirac equation are discussed. The original form of the Dirac impulse approximation follows from using Fermi covariants (scalar, vector, tensor, pseudoscalar, and axial vector) to extend physical NN amplitudes into operators in the full Dirac space. Overly large scalar and vector optical potentials are shown to follow at low energy in this case due to forcing pion exchange contributions to be pseudoscalar. The pair contributions to proton-nucleus scattering are much too large at low energy. A variant of the impulse approximation is developed by replacing pseudoscalar covariants by pseudovector ones. Much reduced scalar and vector strengths are obtained at low energy in the pseudovector case. The pair contributions are similarly reduced to reasonable values. However, the large differences between optical potentials based on pseudoscalar and pseudovector covariants are not controlled by physical NN scattering data. These differences represent a basic ambiguity in NN amplitudes when the only constraint is positive energy scattering data. Using a complete and unambiguous set of NN Lorentz invariant amplitudes obtained from a relativistic one-meson-exchange model, the scalar and vector optical potential strengths are found to be reasonably constant over the range of 50 to 1000 MeV of proton energy. The meson theory results for nuclear matter are found to be comparable to those obtained when the pseudoscalar covariant is replaced by the pseudovector covariant in the original impulse approximation.

Mass separated ${}_{}{}^{117}{}_{}{}^{}\to _{}^{117}{}_{}{}^{}$I${\to }^{117}$Te decays were studied on-line by bombarding ${}_{}{}^{104}{}_{}{}^{}\mathrm{Pd}$ with 86 MeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ions and off-line by bombarding ${}_{}{}^{107,109}{}_{}{}^{}\mathrm{Ag}$ with 50-70 MeV ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$. From gamma ray and x ray singles, half-life, excitation function, and coincidence measurements, 26 gamma rays are assigned to the deccay of ${}_{}{}^{117}{}_{}{}^{}\mathrm{Xe}$ and 31 gamma rays are assigned to the ${}_{}{}^{117}{}_{}{}^{}\mathrm{I}$ decay. The half-lives were measured to be 61±2 sec, 2.22±0.04 min, 62±2 min, and 2.8×0.2 h for ${}_{}{}^{117}{}_{}{}^{}\mathrm{Xe}$, ${}_{}{}^{117}{}_{}{}^{}\mathrm{I}$, ${}_{}{}^{117}{}_{}{}^{}\mathrm{Te}$,, and ${}_{}{}^{117}{}_{}{}^{}\mathrm{Sb}$, respectively. Eight new levels are deduced in ${}_{}{}^{117}{}_{}{}^{}\mathrm{I}$ and seven new levels in ${}_{}{}^{117}{}_{}{}^{}\mathrm{Te}$. From the Kurie plot of the positron spectrum, the ${\mathit{Q}}_{\mathrm{EC}}$${(}^{117}$Xe${\to }^{117}$I) was determined to be ≥6.27±0.30 MeV.

Using the classical picture of the collective M1 mode in nuclei as an oscillation of the angle between the deformed valence protons and valence neutrons, we obtain an expression for the classical limit of the neutron-proton interacting boson model Hamiltonian. We use this result to contrast the excitation energy in the classical limit to the experimentally observed value for the 1sup+ state in sup156Gd.

The pairing problem is treated by means of the equations of motion for zero-coupled pair operators. Exact equations for the seniority-v states of N particles are derived. These equations can be solved by a step-by-step procedure which consists of progressively adding pairs of particles to a core. The theory can be applied at several levels of approximation depending on the number of core states which are taken into account. Some numerical applications to the treatment of v=0, v=1, and v=2 states in the Ni isotopes are performed. The accuracy of various approximations is tested by comparison with exact results. For the seniority-one and seniority-two problems it turns out that the results obtained from the first-order theory are very accurate, while those of higher order calculations are practically exact. Concerning the seniority-zero problem, a fifth-order calculation reproduces quite well the three lowest states.

The angular distributions of both the differential cross section and the analyzing power are presented for the sup10B(p→,πsup+) sup11B reaction leading to the ground and first excited states of sup11B. The differential cross section shows very little angular structure or energy dependence, but the analyzing power exhibits a considerable energy dependence for both states. This dependence, similar to that observed for the sup12C(p→,πsup+) sup13C reaction, may be a signature of the fact that single-particle final states are involved.

Cross sections were measured by the radiochemical method for the formation of sup57Co in the interactions of 6.4 to 9.5 MeV neutrons with nickel. The only contributing process up to 8.3 MeV is the sup58Ni(n,d)sup57Co reaction; between 8.4 and 9.5 MeV, however, small contributions (<10%) from (n,n’p) and (n,pn) processes are also expected. The excitation function shows a rapid increase beyond 8 MeV, reaching almost the maximum at about 15 MeV. Hauser-Feshbach calculations on the first-chance emission of a deuteron show that beyond 11 MeV the relative contribution of the statistical processes decreases and at about 15 MeV it is <30% of the total (n,d) cross section. Calculations involving precompound effects (reported in the literature) seem to agree with the experimental trend over the energy range of 9 to 15 MeV within a factor of 2.

The ratio of the 166° c.m. to 90° c.m. and of the 178.5° c.m. to 90° c.m. differential cross section for neutron-proton scattering has been measured between 40 and 75 MeV. The trend of our data is slightly higher than the present phase-shift analysis.

A particle-gamma coincidence experiment following the sup62Ni(sup27Al,xnypzαγ) fusion-evaporation reaction was performed to decide between two alternative proposals for the sup86Y yrast decay scheme. The results verify the scheme found via the sup76G+ sup14N and sup73Ge+ sup16O reactions. It is suggested that the decay scheme seen in sup85Rb+α is actually associated with sup86Rb. The sup86Y decay scheme is compared with a large basis shell model calculation.

The spin and parity of the 9.065 MeV state in sup32S, populated in the sup28Si(α,γ) sup32S reaction, has been found to be 4sup+. Therefore, this state cannot be the second member of a band based on the proposed 0sup+ shape isomer at 8.507 MeV in sup32S. In the same reaction, no evidence for the 0sup+ and 4sup+ states at 8.507 and 10.276 MeV was found.

A method is presented for the explicit construction of a family of equivalent local potentials from a given nonlocal separable potential. This procedure can be also applied in the case when a Coulomb potential is added to the separable short range interaction.

A first systematic attempt to extract the transverse sum rule from experimental data on sup40Ca, sup48Ca, and sup56Fe is made. The comparison with the theoretical predictions in a correlated model for the ground states, considering tensor correlations explicitly, turns out to be satisfactory. The necessity of invoking modifications of the nucleon properties when immersed in the nuclear medium is discussed.

The question of the origin of the missing M2 strength in sup12C is examined. A large scale shell model calculation of 2sup- states and their decay is presented. It indicates that the role of 2p-2h correlations is probably the most important in explaining the M2 quenching and that the two-body spin-orbit force is instrumental in inducing such a quenching. The role of the tensor force as well as of the Δ-N excitations remains fairly modest.