Excitation functions have been measured for the production of isotopes of Bk through Fm in bombardments of ${}_{}{}^{249}{}_{}{}^{}\mathrm{Cf}$ with 90- to 150-MeV ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ions. A comparison of the maxima of the mass-yield curves measured in this experiment with those for the reactions of ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ ions with ${}_{}{}^{249}{}_{}{}^{}\mathrm{Cf}$ shows different shifts from those that have been measured for reactions of the ${}_{}{}^{16}{}_{}{}^{}$,18O and ${}_{}{}^{20}{}_{}{}^{}$,22Ne ion pairs with ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$. However, the shifts appear similar to those recently measured for reactions of these ion pairs with ${}_{}{}^{254}{}_{}{}^{}\mathrm{Es}$.

The lowest members of the ${}_{}{}^{176}{}_{}{}^{}\mathrm{Lu}$ ground-state band have been Coulomb excited by ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ ions. From the observed branching ratios and angular distribution coefficients, we obtain $G^{\mathrm{KK}}$/$Q_0$=0.18(1). Combining this result with the known magnetic moment of the ground state, we derive $g_R$=0.288(9) and &)=0.953(3). These values are in substantial agreement with semiempirical model predictions.

The inelastic scattering of ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ on ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ has been studied at 500 and 600 MeV incident energies. High statistics spectra were measured at the grazing angle. For each target, spectra at the two incident energies were compared by means of cross correlation analysis. Structures were observed in the inelastic spectra, but they appeared at different excitation energies at the two beam energies and therefore cannot be identified with high-excitation energy states of the target nuclei in contradiction to the results of previous experiments. Rather they arise from the decay of discrete unbound states in the projectile-like nuclei which were excited by a one-nucleon-transfer reaction. In particular, the structures observed in the transfer-evaporation continuum of the ${}_{}{}^{20}{}_{}{}^{}$Ne${+\mathrm{}}^{208}$Pb spectra appear to be mainly due to neutron emission from known discrete unbound states in ${}_{}{}^{21}{}_{}{}^{}\mathrm{Ne}$. A relatively low upper limit is given for the production cross section of multiphonon states in these systems.

The first-order optical potential for elastic nucleus-nucleus scattering is derived, taking into account binding and Fermi motion effects through an optimal approximation. The resulting potential is expressed as a product of the projectile elastic form factor times the nucleon-nucleus elastic amplitude (rather than the nucleon-nucleus potential as in the folding model). The effective energy in this amplitude rises with angle and agrees with the usual choice of the folding model for forward angles. The form of the spin-orbit nucleus-nucleus potential for projectiles with spin is discussed as well.

We examine the theoretical mechanisms for producing high-energy photons in the reaction α${+\mathrm{}}^{154}$Sm and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$${+}^{148}$Sm at low bombarding energies. We find that neither potential field nor nucleon-nucleon collisions can account for the measured high-energy tail, leaving the source of these photons a mystery. Further experiments are suggested to help determine the origin of the photons.

Two distinct bands have been populated to high spin in the doubly-odd nucleus ${}_{}{}^{130}{}_{}{}^{}\mathrm{La}$ following the ${}_{}{}^{116}{}_{}{}^{}\mathrm{F}$,5n) reaction at 76 MeV. Both bands consist of strong M1 transitions with weaker E2 crossovers. One band, built on the π$h_{11/2}$⊗ν$h_{11/2}$ configuration, has a small signature splitting (∼50 keV) indicating a slightly triaxial shape. The other band, believed to be built on the π$h_{11/2}$⊗ν$g_{7/2}$ configuration, shows no signature splitting and is predicted to possess a near-axial prolate shape. Both bands show constant alignment with increasing spin with no low frequency band crossings due to the blocking effect of the $h_{11/2}$ proton.

The behavior of very high rotational states of the highly excited compound nuclear systems formed in fusion reactions is studied in the framework of the statistical theory. The very high spin states populated in these reactions results in the observation of phenomena like backbending and yrast traps. The experimental data on the angular momentum limitation on fusion probability are reproduced at higher entropy values. Shape transitions are observed for the systems ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$${+}^{12}$C, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$${+}^{16}$O, ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$${+}^{18}$O, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${+}^{40}$Ca. We predict a shift in the yrast minima towards higher angular momentum states in the case of ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$${+}^{40}$Ca with the increase in the excitation energy and the entropy of the compound nuclear system. Lines of constant entropy or constant level density are found to be almost equally spaced.

The differential cross section for the excitation of the unbound $3^{+}$ (2.18 MeV) state in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ was measured by scattering a 227 MeV ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ beam from a ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ target. Additionally, the cross section for the $3^{\mathrm{-}}$ (3.74 MeV) state in ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ was measured at the same center-of-mass energy by scattering a 34 MeV ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ beam from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. The cross section for excitation of the $3^{+}$, 2.18 MeV state in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ is 3–5 times larger than that of the ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ $3^{\mathrm{-}}$ state. The present data and previously measured elastic scattering data have been analyzed in the framework of both distorted-wave Born approximation and coupled channels calculations, using double folded real potentials, to determine the influence of the inelastic states on the elastic scattering cross section. We find that the elastic scattering is very sensitive to coupled channels effects arising from the $3^{+}$ state in ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$.

We have examined relativistic nuclei of krypton, xenon, holmium, and gold, accelerated in a partially stripped state to a maximum rigidity of about 5.6 GeV, interacting with targets of aluminum, carbon, and polyethylene. For each projectile and target combination we determined the total and partial charge changing cross sections for the production of lighter fragments. From these measurements we have developed a new representation of the dependence of the total charge changing cross sections on beam and target charge. We have also identified simple representations of the variation of the partial cross sections with the charge of the produced fragments and shown that they are dependent on the charge and energy of the beam. The fission of gold nuclei at high energies in these various targets has also been studied.

The giant dipole resonance built on excited states was studied in ${}_{}{}^{110}{}_{}{}^{}$,112Sn nuclei at excitation energies of 62, 80, 110, and 130 MeV, by measuring γ rays following heavy ion fusion reactions ${}_{}{}^{16}{}_{}{}^{}$O${+\mathrm{}}^{94}$Mo and ${}_{}{}^{19}{}_{}{}^{}$F${+\mathrm{}}^{93}$Nb. The energy of the dipole resonance was found to be 14.8±0.4 MeV independent of excitation energy. This value is approximately 1 MeV below the extrapolated ground state value. The width increases almost quadratically from 6.7 MeV at 62 MeV to 10.8 MeV at 130 MeV. This agrees qualitatively with a theoretical prediction that the increase in width for these nuclei is mainly due to an averaging of strength functions over various oblate shapes induced at high spin and temperature. The sensitivity to the isovector quadrupole vibration was found to be small even at the highest excitation energy. No convincing conclusion could be made for its existence in these Sn nuclei.

The thermal-neutron fission cross section of ${}_{}{}^{235}{}_{}{}^{}\mathrm{U}_{}^{\mathrm{m}}{}_{}{}^{}$ has been measured relative to the ground-state cross section. A rapid radiochemical separation procedure was developed to provide sizeable (${10}^{10}$ to ${10}^{11}$ atom) samples that were reasonably free of the parent ${}_{}{}^{239}{}_{}{}^{}\mathrm{Pu}$. From a series of eight measurements, the value of 1.42±0.04 was obtained for the ratio ${\sigma }_m$/${\sigma }_g$.

A model developed previously to treat p${+\mathrm{}}^4$He scattering at intermediate energies is applied to the case of p${+\mathrm{}}^3$He scattering. The scattering amplitude is written as a sum of direct and exchange terms. The direct-plus-knockout exchange terms are approximated by a phenomenological optical potential scattering amplitude. The heavy particle stripping term, representing the exchange of a neutron-proton cluster between projectile and target, is calculated using a modified distorted-wave Born approximation approach. The point-nucleon wave function for the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ target is determined from a fit to the charge form factor, after subtraction of recently calculated meson exchange current contributions. The back-angle rise in the differential cross section in the energy range 150–600 MeV is reproduced qualitatively when the heavy particle stripping term is included. In addition, a slight improvement in the large angle analyzing power is obtained at 300 and 515 MeV.

A quark compound bag model has been constructed to describe NN s-wave scattering up to 1 GeV. The model contains a vertex interaction $H_{\mathrm{D}\mathit{\leftrightarrows }\mathrm{NN}}$ for describing the excitation of a confined six-quark bag state, and a meson-exchange interaction obtained from modifying the phenomenological core of the Paris potential. Explicit formalisms and numerical results are presented to reveal the role of the bag excitation mechanism in determining the relative wave function and the P and S matrices of NN scattering. We explore the merit as well as the shortcomings of the quark compound bag model developed by the Institute of Theoretical and Experimental Physics group. It is shown that the parameters of the vertex interaction $H_{\mathrm{D}\mathit{\leftrightarrows }\mathrm{NN}}$ can be more rigorously determined from the data if the concept of the chiral/cloudy bag model is used to justify the presence of the background meson-exchange interaction inside bag excitation region. The application of the model to the study of quark degrees of freedom in nuclei is discussed.

We use the new set of Faddeev amplitudes obtained by Garcilazo in order to investigate the effects of the short range ΔN interaction on the values of observables in πd elastic scattering. Using all existing data on total and differential cross sections and on the vector analyzing power, we show that the inclusion of ${}_{}{}^5{}_{}{}^{}\mathrm{S}_2^{}{}_{}{}^{}$ and ${}_{}{}^5{}_{}{}^{}\mathrm{P}_3^{}{}_{}{}^{}$ ΔN interactions leads to a very satisfactory description of the experimental results. The modifications in Garcilazo’s set of πd amplitudes required to incorporate the ΔN interaction effects involve only the ${}_{}{}^3{}_{}{}^{}\mathrm{P}_2^{}{}_{}{}^{}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{D}_3^{}{}_{}{}^{}$ πd waves and are shown to be small, although with strong influence on the observables where discrepancies are eliminated. Predictions are presented for the values of $t_{20}^{\mathrm{lab}}$ and other quantities. The values obtained for the ΔN parameters show a smooth energy dependence, and their determination is an important result of the present work. No resonantlike character is found in the behavior of the ${}_{}{}^5{}_{}{}^{}\mathrm{S}_2^{}{}_{}{}^{}$ and ${}_{}{}^5{}_{}{}^{}\mathrm{P}_3^{}{}_{}{}^{}$ amplitudes, although a ‘‘bound state’’ in the ${}_{}{}^5{}_{}{}^{}\mathrm{S}_2^{}{}_{}{}^{}$ amplitude is compatible with our results. A discussion is made comparing the ΔN and the NN systems in light of the quantum chromodynamics and Skyrme models.

The relation between the nucleon-nucleon interaction and exchange currents needed for current conservation are derived for the Bethe-Salpeter formalism, and for the approach in which the spectator particle is restricted to its mass shell. For both approaches, it is shown how to achieve current conservation for a completely general isospin dependent, energy dependent interaction with arbitrary phenomenological electromagnetic form factors for the nucleon and mesons, and with strong form factors at the meson-nucleon vertices. Contrary to what has often been stated in the literature, the development shows that current conservation places no restrictions on the use of different electromagnetic form factors for mesons and nucleons, and that phenomenological meson-nucleon form factors can be introduced in a way which is consistent with current conservation. The longitudinal part of the exchange current is uniquely determined by current conservation, and for the common case of an interaction that only depends on the invariant momentum transfer variable an explicit expression for this longitudinal exchange current is given. The transverse part, which contains all electromagnetic form factors, is unconstrained by current conservation.

Atomic and nuclear complex energy (Gamow) states of the p¯p system are calculated with the Graz potential. The Coulomb force is included exactly (numerically), separate channels and experimental masses are used for p¯p and n¯n, and absorption is included via a phenomenological annihilation channel. Significant model dependence of the n=1 ${}_{}{}^1{}_{}{}^{}\mathrm{S}_0^{}{}_{}{}^{}$ protonium level is found, as is a possible systematic difference among most calculations and recent experiments. Bound and resonant states of baryonium are found in a number of charge and isospin channels, some with widths as narrow as 16 MeV. Unphysical zero width states are also found and analyzed.

Differential cross sections were measured for pion inelastic scattering from ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$ at $T_{\pi }$=180 MeV. The low-lying collective states were analyzed using distorted-wave impulse-approximation calculations with transition densities obtained from electron and previous pion scattering. The cross sections for ${\pi }^{\mathrm{-}}$ and ${\pi }^{+}$ scattering to the low-lying collective states are nearly equal. Neutron and proton matrix elements have been extracted from simultaneous fits to ${\pi }^{\mathrm{-}}$ and ${\pi }^{+}$ data. The resulting values are in good agreement with data from hadronic and electromagnetic probes.

The effects of charge-symmetry breaking of nuclear forces can be observed in neutron-proton elastic scattering. We present and apply a formalism used to compute the effects. The major contributions arise from the neutron-proton mass difference in one-pion and one-rho exchanges, from the neutron anomalous magnetic moment in one-photon exchange, and from rho-omega meson mixing. Two-pion exchange and quark effects were found to be very small. We find our results in agreement with the one existing measurement.

The contributions from two-body exchange current and wave function renormalization are shown to cancel each other in the soft-pion limit using generalized Ward-Takahashi relations. For conserved vector current, the cancellation is complete; for partially conserved axial-vector current, the cancellation is partial with the remainder related to the pion-bremsstrahlung process in nucleon-nucleon scattering. The implications of the results for the weak decay processes in finite nuclei are discussed.

Double differential cross sections $d^2$σ/dΩ${\mathrm{dT}}_{\mathrm{n}}$ for the production of neutrons from 585 MeV proton bombardment of C, Al, Fe, Nb, In, Ta, Pb, and U targets have been measured at emission angles of 30°, 90°, and 150° and for neutron kinetic energies between 0.9 and 585 MeV (all quantities in the laboratory system). The measured cross sections are compared with previous experimental results from other laboratories. The experimental energy-dependent cross sections all reveal a clear two-component structure with contributions from evaporation processes and intranuclear cascade reactions. For heavy and medium weight target nuclei the data in the evaporation region are indicative of an isotropic angular distribution in the zero linear momentum coordinate system. Data in the cascade energy region are strongly forward peaked, and the fraction of cascade neutrons increases with decreasing emission angle. This fraction also increases with decreasing mass number.