We have measured doubly differential cross sections for the (${\pi }^{+}$,${\pi }^0$) and (${\pi }^{\mathrm{-}}$,${\pi }^0$) reactions at 120- and 230-MeV kinetic energies for ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}$, and ${}_{}{}^{120}{}_{}{}^{}\mathrm{Sn}$. Nuclear-excitation energies up to 60 MeV were observed. We have extracted excitation energies, widths, and maximum cross sections for the isospin components of the isovector monopole resonance and the isovector dipole resonance. The excitation energies and widths from the present data and from earlier measurements at 165 MeV are compared and found to be in agreement. The cross sections for the isovector monopole and isovector dipole resonances show the same increase with bombarding energy in all targets. No isovector quadrupole strength is required to fit the experimental data. We compare the energy dependences of the isovector-resonance cross sections with those of isobaric-analog states, and to distorted-wave impulse approximation calculations.

We lay down the formalism for the treatment of pionic atoms level widths and shifts using the Kemmer-Duffin-Petiau equation. Interactions are introduced in a Lorentz invariant way. An analytical transformation is shown that connects between different sets of interactions. The Kisslinger potential is obtained as a special case of a scalar-tensor optical potential. Results are shown in the accompanying paper.

Fits to data on strong interaction level shifts and widths in pionic atoms, over the whole of the periodic table, are made with the Kemmer-Duffin-Petiau equation. Comparisons are made with the conventional Klein-Gordon equation and emphasis is placed on the problem of anomalously small shifts and widths. The Kemmer-Duffin-Petiau equation yields fits which are marginally better than those obtained with the Klein-Gordon equation.

The $t_{1/2}$=5.7 min ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ isotope was produced in the ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$(n,p) reaction and its subsequent β decay back to ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$ was studied with a Ge(Li) spectrometer. A radiochemical technique was used to measure the fractional population of the $I^{\pi }$, K${=(8\mathrm{}}^{\mathrm{-}}$,8) isomer in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$ to be $f_m$=0.005±0.018? The limit on $f_m$ is shown to be too small to account for the nucleosynthesis of ${}_{}{}^{180}{}_{}{}^{}$${\mathrm{Ta}}^{\mathrm{m}}$ in the r process. The possible existence of a high-spin isomer in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ and its astrophysical consequences are discussed.

Searches have been made for short-lived isomers in ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ suggested by the preceding paper. Samples of ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ were produced via the ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}$(n,p) reaction. Evidence for decay of a ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ isomer was sought by examining the decay curves of the known ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ and ${}_{}{}^{180}{}_{}{}^{}\mathrm{Hf}_{}^{\mathrm{m}}{}_{}{}^{}$ delayed γ rays, and by searching for previously unidentified delayed γ rays. No evidence for a ${}_{}{}^{180}{}_{}{}^{}\mathrm{Lu}$ isomer was observed for half-lives between 10 and 300 sec. The relevance of these observations for understanding the nucleosynthesis of ${}_{}{}^{180}{}_{}{}^{}$${\mathrm{Ta}}^{\mathrm{m}}$ is discussed.

Estimates are given for half-lives of the radioactive decay of radium and radon isotopes by emission of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ nuclei. The classical one-dimensional WKB approximation for penetration through a pure Coulomb barrier is used in the calculations. Results indicate that naturally occurring radon isotopes are ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ emitters like their parent radium isotopes, whose decay rates by emission of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ nuclei have recently been measured. The predicted half-lives for decay of ${}_{}{}^{219}{}_{}{}^{}\mathrm{Rn}$, ${}_{}{}^{220}{}_{}{}^{}\mathrm{Rn}$, and ${}_{}{}^{222}{}_{}{}^{}\mathrm{Rn}$ by emission of ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ nuclei are in the range ${10}^{11}$–${10}^{14}$ yr. For radium and radon isotopes the minimum half-life is obtained when the double-magic ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ and the semimagic ${}_{}{}^{206}{}_{}{}^{}\mathrm{Hg}$, respectively, are the daughter products of these new radioactive decay modes.

The relation between the two kinds of dynamical symmetry models in nuclear structure physics, the well-known interacting boson model and the recently proposed fermion dynamical symmetry model, is studied from group theoretical point of view. A one-to-one correspondence is established between the generators, building blocks, irreducible basis vectors and the invariants of the subgroups SO(5), SO(6), and SU(3) contained in the dynamical group chains of the interacting boson model and those of the fermion dynamical symmetry model.

Shell-model calculations are presented for electric quadrupole moments of A=17–39 nuclei. The shell-model wave functions, which span the complete 0$d_{5/2}$-l$s_{1/2}$-0$d_{3/2}$ model space in all instances, are obtained by diagonalizing an sd-shell Hamiltonian which consists of a fixed single-particle energy spectrum and a single set of two-body matrix elements scaled as a function of the mass number A. Results obtained with harmonic oscillator and Saxon-Woods single-particle radial wave functions and matched effective-charge models are presented for ground states of odd-even and doubly odd nuclei and for $J^{\pi }$${=2\mathrm{}}^{+}$ first-excited states of doubly even sd-shell nuclei.

In the framework of the Sp(1,R) model for the monopole oscillations, we examine how the ground state correlations affect the monopole operator sum rules $m_l$, 0≤l≤3, in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$. Our way of probing the correlations indicates their importance for the even sum rules, whereas the odd ones practically are not affected by it. Since the scaling incompressibility is proportional to $m_3$, we also conclude that the scaling incompressibility is not sensitive to ground state correlations. The above conclusions are in agreement with the random-phase approximation results.

As a model for nuclear matter based on quark clustering, we consider a system of fermions carrying color, interacting through a δ-function potential in one dimensional space. The dynamical properties of the system are studied by the variational method as a function of density. We develop a trial wave function for triplet (three-quark) clusters in analogy to the BCS wave function for pairs in the theory of superconductivity. We show that the system consists of a Fermi gas of color-neutral triplet clusters (nucleons) at low density and a Fermi gas of quarks in the limit of high density. The low density result agrees with the exact result derived by the method of the Bethe ansatz through second order in density.

The deformed nucleus ${}_{}{}^{148}{}_{}{}^{}\mathrm{Ba}$ (populated in ${}_{}{}^{148}{}_{}{}^{}\mathrm{Cs}$ decay) is the heaviest Z=56 and the lightest N=92 nucleus known; thus its levels are extrapolations of both Z and N systematics. Values for E${(2\mathrm{}}_1^{+}$), E${(4\mathrm{}}_1^{+}$)/E${(2\mathrm{}}_1^{+}$), and E${(2\mathrm{}}_2^{+}$) are in excellent agreement with interpolative predictions from systematics of the valence-nucleon product $N_{\mathrm{p}{N}_{\mathrm{n}}}$.

The ground-state Q value for the ${}_{}{}^{80}{}_{}{}^{}\mathrm{Kr}$(d,p${)}^{81}$Kr reaction has been determined by extrapolating to 0.0 MeV excitation the Q values measured for nine excited states in ${}_{}{}^{81}{}_{}{}^{}\mathrm{Kr}$. (The ground state is not observed.) Peaks from the ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$(d,p${)}^{29}$Si reaction served as energy calibration points. A ground-state Q value of 5646±4 keV was found for the ${}_{}{}^{80}{}_{}{}^{}\mathrm{Kr}$(d,p${)}^{81}$Kr reaction. A ground-state mass excess for ${}_{}{}^{80}{}_{}{}^{}\mathrm{Kr}$ of -77 898±7 keV was deduced using recent ${}_{}{}^{81}{}_{}{}^{}\mathrm{Kr}$ ground-state mass measurements and the ${}_{}{}^{80}{}_{}{}^{}\mathrm{Kr}$(d,p${)}^{81}$Kr Q value from the present work.

With the use of Ge(Li) detectors for gamma ray yield measurements, several resonances were located in proton-induced reactions on a ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ target for bombarding energies of $E_{\mathrm{p}=3.1\mathrm{}–}$3.6 MeV ($E_x$=14.62–15.04 MeV in ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$). Decay modes of the resonances were determined.

Directional correlation measurements with a Ge-Ge(Li) coincidence spectrometer were made on thirteen gamma ray cascades in ${}_{}{}^{214}{}_{}{}^{}\mathrm{Po}$, the levels of which were excited by the ${\beta }^{\mathrm{-}}$ decay of 19.7 min ${}_{}{}^{214}{}_{}{}^{}\mathrm{Bi}$. Spins were deduced for twelve levels in ${}_{}{}^{214}{}_{}{}^{}\mathrm{Po}$ and the mixing ratio, δ, determined for eleven transitions.

A coupled-channels Born approximation formalism for breakup reactions recently proposed by Udagawa and Tamura is compared with the distorted-wave Born approximation formalism discussed by Ichimura, Austern, and Vincent. Udagawa and Tamura claimed that the distorted-wave Born approximation method erroneously includes pure inelastic scatterings. We show that their argument is invalid and that there is no asymptotically observable inelastic scattering in the distorted-wave Born approximation breakup formalism.

A comparative study of various representations of the shell model density of states, given its first four moments (centroid, width, skewness, and excess) is made. The Cornish-Fisher representation, which is obtained by the variable transformation method, is shown to be useful in studies using spectral distribution methods.

Using a microscopic semiclassical approach we analyze the effect of deformation on the splitting of giant dipole resonances and consequently on the observed experimental widths. We study the behavior of the width for the Nd, Sm, Sn, and Mo chain of isotopes. Altogether these effects can account for 30–40 ?f the observed widths.

A compact general expression for the differential cross section of the photonuclear reaction (γ, N), in which the incident photon is circularly polarized and any polarization of the emitted nucleon observed, is presented. Angular distribution coefficients relevant to the nucleon polarization in the scattering plane are expressed as bilinear combinations of matrix elements for a special case of the ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(γ,${\mathrm{N}}_0$) reaction. The polarization $P_x$, calculated within the direct-semidirect model at $E_{\gamma }$=60 MeV, is shown as an example of the theoretical result.

The electromagnetic self-energy of the quantized Skyrmion is calculated. A Lamb-shift type of approach yields the right sign but too small a magnitude for standard parametrizations.

We analyze various truncation schemes for the physical boson basis states which are required for the calculations in the boson space, in the Dyson boson mapping formalism. The available approximate schemes violate the Pauli principle and are found to be inadequate. The necessity to evolve yet a reliable and useful truncation scheme is stressed.