The method used to define relativistic one-, two-, and three-particle states with spin in the z basis and the helicity basis is described, and the Lorentz transformation and improper transformation properties of these states are discussed. The three-body states are used to construct a relativistic, three-body, angular-momentum recoupling coefficient. A detailed derivation of this recoupling coefficient in both the z basis (LS coupling scheme) and the helicity basis is presented, and an expression for the nonrelativistic limit of this recoupling coefficient (i.e., neglecting Wigner spin precession) is given. Uses of these states in relativistic potential theory and optical model problems is also discussed.

A πNN theory, incorporating mesonic and dibaryonic excitation mechanisms, is introduced to give a unified description of NN and πd reactions. The mesonic mechanism is built into the theory by extending the conventional meson theory of nuclear force to include the isobar Δ excitation. The dibaryonic excitation at short distance is introduced according to current understanding of six-quark dynamics. The theory is free of the nucleon mass renormalization problem and is therefore tractable in practice. The model Hamiltonian consists of (a) $V_{\mathrm{BB}}$ for two-baryon interactions between NN, NΔ, and ΔΔ states; (b) $h_{\pi \mathrm{N}\mathit{\leftrightarrows }\mathit{\Delta }}$ for Δ excitation; (c) $v_{\pi \mathrm{N}}$ for πN two-body interaction in nonresonant channels; (d) $F_{\pi \mathrm{NN}\mathit{\leftrightarrows }\mathrm{NN}}$ for nonresonant pion production; and (e) $H_{D\leftrightarrows \mathrm{BB}}$ for the formation of a dibaryon state D. Dynamical equations for NN and πd scattering are derived by making the assumption that all NN and πd processes can be described in a subspace spanned by NN, NΔ, ΔΔ, πNN, and the dibaryon state D. The resulting scattering theory satisfies the essential two-body (NN) and three-body (πNN) unitarity relations. The projection technique is applied to cast the theory into a form such that all NN and πd reaction transition matrix elements can be calculated by solving, separately, a two-body integral equation and a Faddeev-type three-body equation. Both can be solved by well-established numerical methods. This makes the calculation based on the most sophisticated meson theory of nuclear force possible. Explicit formalisms have also been developed for exploring the question of the excitation of a dibaryon resonance during NN and πd scattering from the point of view of six-quark dynamics. The numerical results obtained from the theory are presented in a separate paper.

We examine how the Pauli exclusion principle affects the pion-nucleus optical potential U in the region of the ${\Delta }_{33}$ resonance, i.e., for pion kinetic energies of 50–300 MeV. In our formulation the exchange effects enter through n-body correlation functions and contribute to U as higher-order corrections in a density expansion. We study the rate of convergence of the expansion and derive an integral equation that sums selected exchange terms to all orders. We calculate the isoscalar, isovector, and isotensor components of U for the cases of infinite nuclear matter and finite nuclei. We identify the limiting conditions under which our treatment of the Pauli effect reduces to that in more familiar approaches.

We discuss the importance of the A(e,e’${\mathrm{K}}^{+}$${)}_{\mathrm{\Lambda }}$${\mathrm{A}}^{\mathrm{*}}$ in hypernuclear physics, comparing it with the A(${\mathrm{K}}^{\mathrm{-}}$,${\pi }^{\mathrm{-}}$${)}_{\Lambda }$$A^{\mathrm{*}}$ reaction and suggesting problems that can preferentially be studied with the (e,e’${\mathrm{K}}^{+}$) probe. Cross sections are given for exclusive and inclusive processes for a large range of nuclear masses. The elementary process p(e,e’${\mathrm{K}}^{+}$)Λ is not well known, and the coupling constants and electromagnetic moments are discussed.

The contribution of two-step processes in quasielastic nucleon-nucleus collisions is estimated. We use a simple model for the single-step inelastic excitation based on the random-phase-approximation response of semi-infinite nuclear matter. In the 200 MeV (p,n) reaction on ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$, the two-step background is found to be significant, contributing about 15% at 13° scattering angle in the quasielastic peak region. The relative magnitude of the two-step contribution depends strongly on energy, becoming less important in the 800 MeV (p,p’) reaction on ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$.

Results are presented for a two-nucleon model of the (p,π) reaction in the resonance region. Features of the microscopic two-nucleon model adopted include propagating intermediate pions and rho mesons, and an intermediate delta isobar whose propagator includes interaction with the nuclear system as well as an energy dependent width. Realistic distorted waves are adopted for the external proton and pion. Transitions from a closed shell to two-particle–one-hole and single-particle final states are studied, with both projectile- and target-emission diagrams included, for a carbon target. The results indicate that the effect of finite range delta propagation is important in lowering the sensitivity of the predictions to the details of proton and pion distortions and the bound state wave functions. The results are not very sensitive to the exact nature of the delta-nucleus interaction. The relative magnitude of target-emission or projectile-emission diagrams depends on the particular transition and angle under consideration. Comparison with experiment and future extensions and applications of the model are discussed.

The great majority of the known nuclides with Z>40, including the so-called stable nuclides, are metastable with respect to several modes of spontaneous superasymmetric splitting. A model extended from the fission theory of alpha decay allows one to estimate the lifetimes and the branching ratios relative to the alpha decay for these natural radioactivities. From a huge amount of systematic calculations it is concluded that the process should proceed with maximum intensity in the trans-lead nuclei, where the minimum lifetime is obtained from parent-emitted heavy ion combinations leading to a magic ${(}^{208}$Pb) or almost magic daughter nucleus. More than 140 nuclides with atomic number smaller than 25 are possible candidates to be emitted from heavy nuclei, with half-lives in the range of ${10}^{10}$–${10}^{30}$ s: ${}_{}{}^5{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{8–10}{}_{}{}^{}\mathrm{Be}$, ${}_{}{}^{11}{}_{}{}^{}$,12B, ${}_{}{}^{12–16}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{13–17}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{15–22}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{18–23}{}_{}{}^{}\mathrm{F}$, ${}_{}{}^{20–26}{}_{}{}^{}\mathrm{Ne}$, ${}_{}{}^{23–28}{}_{}{}^{}\mathrm{Na}$, ${}_{}{}^{23–30}{}_{}{}^{}\mathrm{Mg}$, ${}_{}{}^{27–32}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{28–36}{}_{}{}^{}\mathrm{Si}$, ${}_{}{}^{31–39}{}_{}{}^{}\mathrm{P}$, ${}_{}{}^{32–42}{}_{}{}^{}\mathrm{S}$, ${}_{}{}^{35–45}{}_{}{}^{}\mathrm{Cl}$, ${}_{}{}^{37–47}{}_{}{}^{}\mathrm{Ar}$, ${}_{}{}^{40–49}{}_{}{}^{}$ K, ${}_{}{}^{42\mathrm{-}51...}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{44–53}{}_{}{}^{}$ Sc, ${}_{}{}^{46–53}{}_{}{}^{}\mathrm{Ti}$, ${}_{}{}^{48–54}{}_{}{}^{}\mathrm{V}$, and ${}_{}{}^{49–55}{}_{}{}^{}$ Cr. The shell structure and the pairing effects are clearly manifested in these new decay modes.

The techniques of nuclear orientation and nuclear magnetic resonance on oriented nuclei were applied to ${}_{}{}^{188}{}_{}{}^{}\mathrm{Ir}$ after recoil implantation into Fe and Ni. Combining the results of nuclear orientation and nuclear magnetic resonance on oriented nuclei, which are sensitive to the magnetic moment and the g factor, respectively, the spin of ${}_{}{}^{188}{}_{}{}^{}\mathrm{Ir}$ was determined to be I=1, in contradiction to I=2 adopted previously. In addition, the splitting of the nuclear magnetic resonance on oriented nuclei resonance into two subresonances due to quadrupole interaction was observed, which proves again I=1.

The magnetic and electric hyperfine splitting frequencies, ${\nu }_M$=‖g${\mu }_{\mathrm{N}{B}_{\mathrm{HF}/\mathrm{h}\mathrm{\Vert }}}$ and ${\nu }_Q$=$e^2$qQ/h, were determined for ${}_{}{}^{188}{}_{}{}^{}\mathit{Fe}$, ${\nu }_M$=315.8(3) MHz and for ${}_{}{}^{188}{}_{}{}^{}\mathit{Ni}$, ${\nu }_M$=104.8(1) MHz, ${\nu }_Q$=-1.98(4) MHz. Taking into account a 3% uncertainty arising from hyperfine anomalies, the magnetic moment of ${}_{}{}^{188}{}_{}{}^{}\mathrm{Ir}$ is deduced to be ‖μ‖=0.302(10) ${\mu }_{\mathrm{N}}$.

With the electric field gradients of Ir in Fe and Ni, recalculated to be -0.283(6)×${10}^{17}$ V/${\mathrm{cm}}^2$ and -0.151(4)×${10}^{17}$ V/${\mathrm{cm}}^2$, respectively, the spectroscopic quadrupole moment of ${}_{}{}^{188}{}_{}{}^{}\mathrm{Ir}$ is deduced to be +0.543(8) b. The β decay of ${}_{}{}^{188}{}_{}{}^{}\mathrm{Ir}$ to the 2214 keV level in ${}_{}{}^{188}{}_{}{}^{}\mathrm{Os}$ takes place to about 88% with tensor rank 0. Assuming the validity of the ξ approximation, the ratio of the remaining matrix elements is ‖V/Y‖=5.3(1.5). Our measurements show further that nuclear orientation experiments, from which γ-decay properties in ${}_{}{}^{188}{}_{}{}^{}\mathrm{Os}$ have been derived, will have to be reinterpreted. In addition, the spectroscopic quadrupole moments of ${}_{}{}^{192}{}_{}{}^{}\mathrm{Ir}$ and ${}_{}{}^{194}{}_{}{}^{}\mathrm{Ir}$ were redetermined to be +2.28(6) b and +0.339(12) b, respectively.

The relation between the phenomenological Hamiltonian as used in dynamical boson-fermion symmetries and the semimicroscopic Hamiltonian of the interacting boson-fermion approximation, both used in the description of odd-mass nuclei, is studied in detail. Predictions are obtained for the parameters of the boson fermion symmetry Hamiltonian. From the microscopic picture behind the interacting boson-fermion approximation model, predictions are also obtained for the regions in the table of isotopes where the boson-fermion symmetries can be expected to occur. In addition we derive the structure of an additional exchange force, which results from the interaction between like particles.

The properties of high spin spectra of nuclei with stable octupole deformation are discussed in terms of a simple two-j-shell model. The influence of octupole degree of freedom on spin alignment, band interaction, moments of inertia, and pairing field is analyzed.

The energies of muonic x-ray transitions sensitive to the nuclear charge parameters have been measured with a precision up to 9 ppm in muonic ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$. Combining our muonic-atom results for the equivalent nuclear charge radii $R_k$,α with recent elastic electron scattering data, the rms radius of ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ could be determined as 〈$r^2$${〉}^{1/2}$=4.2726(9) fm. In addition to the nuclear monopole charge distribution, nuclear polarization correlations between the muonic 1s and 2s and the 1s and the two 2p states could be determined. With additional constraints from elastic electron scattering and theory, the nuclear polarization corrections of the four lowest-lying states could be evaluated with precisions of the order of 15%. Of particular significance is the result for the two 2p states, because the experimentally determined 2$p_{1/2}$ correction is smaller than the nuclear polarization correction in the 2$p_{3/2}$ state, in contrast to current theoretical models.

The results of radioactivation, mass spectrometric, and fragment detection experiments have been combined to give a complete mass yield distribution for the interaction of silver with 300 GeV protons. Spallation accounts for approximately 80% of the total reaction cross section and fragmentation for nearly 20%.

The neutron-proton total cross section has been measured at 27.1, 39, 52.6, 62.7, and 72.7 MeV, with an error less than 1%. Our high precision data are in good agreement with some of the previous measurements.

The levels in ${}_{}{}^{76}{}_{}{}^{}\mathrm{Kr}$ have been studied in the decay of mass separated ${}_{}{}^{76}{}_{}{}^{}\mathrm{Rb}$. Strong beta population was observed to states above 2 MeV. Numbers of new levels were observed to be populated in this decay including several which populate the $0_2^{+}$ level. These levels help establish the near-spherical nature of the $0_2^{+}$ state.

New experimental data of the kinematically complete differential cross section for the d+p→p+p+n reaction are presented. Evidence is given to explain the major peak occurring in all measurements in terms of a Coulomb effect.

The excitation energies of low lying levels in $F$-spin multiplets are compared. An overall constancy of these energies is found, which indicates that the interacting boson model Hamiltonian has rather constant parameters in the multiplet.

We perform, in the case of particles moving in a single-$j$ level, shell model calculations in which the angular momentum of the individual pairs is restricted to a maximum value. The comparison with the full calculation shows the need for including at least the $G$ pairs in the model space in order to reproduce the correct moments of inertia and transition rates of the different rotational bands. We also show that a level scheme very close to that obtained in the laboratory system can be alternatively obtained by angular momentum projection starting from intrinsic states evaluated in the intrinsic frame.

In a self-consistent cranked Hartree-Fock-Bogoliubov calculation, after the vanishing of pairing correlations, alignment of neutron pairs is seen in the $i_{\frac{13}{2}}$ and $i_{\frac{11}{2}}$ subshells at $I=30\mathrm{} \mathrm{and} 34$ for ${}_{}{}^{172}{}_{}{}^{}\mathrm{Yb}$ and ${}_{}{}^{174}{}_{}{}^{}\mathrm{Yb}$, respectively. In ${}_{}{}^{170}{}_{}{}^{}\mathrm{Yb}$ at $I=42\mathrm{}$, proton alignment occurs in the $h_{\frac{11}{2}}$ and $h_{\frac{9}{2}}$ subshells. These structural changes are also reflected in the $g$ factors.

The abnormal parity components in the deuteron wave function lead to a photon circular polarization asymmetry in the momentum distribution of the outgoing pions in $\gamma \mathrm{d}\to {\pi }^0\mathrm{d}$. An experimental measurement of this asymmetry could lead to a better understanding of the abnormal parity components in the deuteron wave function. It is shown that this asymmetry is of the order of ${10}^{-7\mathrm{}}$-${10}^{-8\mathrm{}}$ and is about the same order of magnitude as the asymmetry in $\mathrm{np}\to \mathrm{d}\gamma$.

Some recent experiments have reported a strong suppression of the $M3\mathrm{}$ part of the elastic magnetic electron scattering in a number of light nuclei. We examine the effect of the first-order as well as second-order perturbative diagrams on the momentum-transfer dependence of the $M1\mathrm{}$ and $M3\mathrm{}$ form factors in the case of a closed $f_{\frac{7}{2}}$ shell plus a neutron employing realistic effective interactions. It is seen that the second-order diagrams play an important role in suppressing the $M3\mathrm{}$ form factor around its first maximum by roughly a factor of 3; the enhanced importance of second-order polarization effects arises partly from the fact that the "dequenching" resulting from the RPA-type graphs is quite small.