Measurements for spin observables for elastic scattering of 320, 400, 500, 650, and 800 MeV protons from ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ are reported. Comparisons of the data with theoretical calculations were carried out in the framework of nonrelativistic and relativistic approaches. The differences between the relativistic and nonrelativistic predictions are found, in agreement with earlier theoretical predictions, to decrease with the increasing energy. The trend can be best seen by examining the data for the spin-down channel differential cross sections. Unlike the spin-up cross sections, they are sensitive to the relativistic corrections. For all targets and energies considered, predictions of the relativistic and nonrelativistic approaches are similar and agree with the spin-up channel data. The predictions differ considerably in the spin-down channel.

The isospin structure of the quadrupole strength in ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$ is examined by a variety of means in an attempt to understand the surprisingly large amount of isovector strength extracted from some recent ${\pi }^{\mathrm{-}}$/${\pi }^{+}$ experiments in the excitation-energy region (below 2ħω) expected for the isoscalar giant-quadrupole resonance. The ratio of the giant-quadrupole resonance neutron and proton multipole matrix elements for ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$ determined from ${\pi }^{\mathrm{-}}$/${\pi }^{+}$ data is $M_{\mathrm{n}/M_{\mathrm{p}=1.9\mathrm{}\pm 0.4}}$ compared to calculations which range from 1.1 to about N/Z (1.36). It is demonstrated that this large ratio has unrealistic consequences in random-phase approximation mixing of the giant states into the first $2^{+}$ state transition (core polarization), which has been independently studied by other probes and is in rather good agreement with quasiparticle random-phase approximation calculations, which have $M_{\mathrm{n}/M_{\mathrm{p}\mathrm{\le }\mathrm{N}/\mathrm{Z}}}$ for the isoscalar giant-quadrupole resonance. Quasiparticle random-phase approximation transition densities are used to calculate pion, proton, and neutron cross sections to the isoscalar giant-quadrupole resonance and the first $2^{+}$ state using microscopic reaction models. A comparison of B(E2) from the same structure model is made to the various data for the first $2^{+}$ transition and to the ${}_{}{}^{116}{}_{}{}^{}\mathrm{Sn}$(e,e’) data on the isoscalar giant-quadrupole resonance. Although not completely conclusive because of the lack of reliable (e,e’) data, the evidence from all these comparisons is that the ${\pi }^{\mathrm{-}}$/${\pi }^{+}$ results are at odds with the results of other probes and with nuclear structure theory and that the problem seems to be with the ${\pi }^{+}$ scattering results.

The sensitivity of neutron-proton elastic scattering observables to variations in the low angular momentum T=0 phase shifts is studied at $E_{\mathrm{lab}=325\mathrm{}}$ MeV. It is found that the J=1 coupling parameter ${\epsilon }_1$ is not well determined by existing data. This uncertainty in ${\epsilon }_1$ permits models with quite different tensor forces to describe the extant data. Implications and possible experimental resolution of such ambiguities are discussed.

Differential cross sections for inelastic pion scattering from ${}_{}{}^{14}{}_{}{}^{}\mathrm{C}$ measured at $T_{\pi }$=164 MeV, for the $2_1^{+}$ and $2_2^{+}$ states and an unresolved peak at 10.4 MeV, were analyzed by distorted-wave impulse approximation and coupled-channel calculations using transition densities derived from large scale shell model calculations. The pion and B(E2) data showed strong quenching of the isovector component for the $2_1^{+}$ transition, which required different effective charges for the p and sd shells. The pion data for the $2_2^{+}$ are an order of magnitude smaller than for the $2_1^{+}$ state, and this was understood in terms of strong cancellations between the neutron and proton transition amplitudes. This transition was found to be very sensitive to details of the calculations. The 10.4 MeV data were consistent with the excitation of a $3^{\mathrm{-}}$ state.

The features of the (N,N’π) reaction are examined at intermediate energies, i.e., for 300–800 MeV incident nucleon energies, when the continuum nucleon and pion are observed in coincidence. In comparison with the (N,π) reaction, which has been studied in considerable detail both theoretically and experimentally, there are some advantages in analyzing the (N,N’π) reaction. Both reactions can deliver large momentum transfer to the nucleus; however, the (N,N’π) reaction can also occur for relatively small momentum transfer (e.g., q≊200 MeV/c). Thus this reaction can be studied in regions where nuclear single-particle wave functions and transition densities are large and well known. In this paper we consider one particular reaction: the exclusive (p,p’${\pi }^{+}$) reaction. For this process we focus on the amplitudes which are dominated by a Δ(1232) resonance in intermediate states. A nonrelativistic formalism for the reaction amplitudes is derived and examined in detail. The theoretical cross sections are shown to be quite sensitive to the pion self-energy, and relatively insensitive to the isobar self-energy in the medium. Furthermore, the calculations suggest that certain amplitudes may dominate the cross sections in different kinematic regions. The differences between relativistic and nonrelativistic approximations for the pion self-energy are examined. Because of the exploratory nature of this investigation, simple forms are used for the bound-state wave functions and transition densities, and the continuum particles are approximated by plane waves; the effects of distorted waves are estimated.

Threefold differential cross sections σ(${\theta }_{\pi }$,${\theta }_{\mathrm{p}}$,$P_{\mathrm{p}}$) have been measured in a kinematically complete experiment. The experiment has been designed to extend earlier measurements into the kinematic region of the np final-state interaction. The data are compared with the predictions from the new relativistic Faddeev theory of Garcilazo.

The vector analyzing power ${\mathrm{iT}}_{11}$ has been measured for the πd breakup reaction in a kinematically complete experiment. The dependence of ${\mathrm{iT}}_{11}$ on the momentum of the proton has been obtained for 36 pion-proton angle pairs at $T_{\pi }$=134 and 228 MeV. The data are compared with predictions from the new relativistic Faddeev theory of Garcilazo. The sensitivity of the observable ${\mathrm{iT}}_{11}$, in particular in the np final-state interaction region, to details of the theory is investigated.

Proton and neutron transition densities in ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$ are examined by a combination of intermediate energy (e,e’) and (p,p’) reactions and mirror electromagnetic transition rates. This analysis is performed for the $2_1^{+}$ and $2_2^{+}$ states at 2.234 and 3.499 MeV in ${}_{}{}^{30}{}_{}{}^{}\mathrm{Si}$. Electron scattering data are presented for these states. Shell-model calculations for the proton and neutron transition matrix elements and proton transition densities are compared with the electromagnetic results. The proton transition densities are reasonably predicted for the $2_1^{+}$ state but are not adequately predicted for the $2_2^{+}$ state. A microscopic coupled-channel calculation of 650 MeV (p,p’) is used to test the shell-model isoscalar transition densities. Given the uncertainties present in the reaction calculation and interaction, the isoscalar density for the $2_1^{+}$ state is found to be adequate, but the density for the $2_2^{+}$ state is less accurate. The coupled-channel effect is shown to be important for the $2_2^{+}$ state. This dependence increases with energy but should be taken into account for an accurate description of (p,p’) reactions at all energies.

The cross sections for inelastic electron scattering from ${}_{}{}^2{}_{}{}^{}\mathrm{H}$ have been measured over a wide kinematic range covering momentum transfers q from approximately 250 to 600 MeV/c. To make longitudinal transverse separations of the response functions, both forward angle (60°) and backward angle (134.5°) data were obtained. The observations are in excellent agreement with calculations of Arenhövel and Leidemann and in slightly less good agreement with the calculations of Laget throughout the quasielastic peak and the ‘‘dip’’ regions.

The Glauber approximation is combined with the interacting boson model of nuclei to describe medium energy proton scattering to collective states. Channel coupling effects are included to all orders. Nonperipheral contributions are found to be nonnegligible, especially for small angles. As an illustration, cross sections for the excitation of the low lying $J^{\pi }$${=0\mathrm{}}^{+}$, $2^{+}$ states in ${}_{}{}^{154}{}_{}{}^{}\mathrm{Gd}$ are presented.

The energy spectra of photons following negative muon absorption in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$, ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, ${}_{}{}^{\mathrm{nat}}{}_{}{}^{}\mathrm{Fe}$, ${}_{}{}^{165}{}_{}{}^{}\mathrm{Ho}$, and ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ have been measured with two NaI spectrometers. The branching ratios for the emission of high energy photons give information on the induced pseudoscalar coupling constant $g_P$ in nuclear matter. The data for light nuclei are in agreement with the theoretical calculations using the nucleonic value of $g_P$≊7$g_A$ predicted by the partially conserved axial vector current hypothesis, while significantly lower values of $g_P$ are required to fit the data of the heavier elements with presently existing theoretical predictions. Disregarding the remaining theoretical uncertainties, these results can be interpreted as a further indication of the renormalization of the nucleonic form factors inside the nucleus.

Nucleon self-energy diagrams, which are necessary to satisfy unitarity in NN scattering above pion production threshold, are studied for a realistic one-boson-exchange model. It is demonstrated that, in the framework of noncovariant perturbation theory, the independent iteration of (lowest order) bubble diagrams at both nucleon lines leads to dressing factors which provide well-defined off-shell corrections to the meson exchange contributions. It turns out that nucleon dressing yields additional attraction in lower partial waves. A slight readjustment of meson parameters (especially a reduction of the cutoff mass in the πNN vertex) leads to a reproduction of the empirical NN data below pion threshold which is of the same quality as before. The resulting inelasticities are, however, much too small, which clearly establishes the need for using a NN potential model containing the Δ isobar explicitly.

We have calculated the $B_{\Lambda }$ value of ${}_{\mathrm{\Lambda }}{}^5{}_{}{}^{}\mathrm{He}$ within the framework of the resonating group method using antisymmetrized α+Λ cluster wave functions and two different effective ΛN interactions. Differing from previous studies, we allow the α particle to have a nonvanishing D-state admixture. We find that the presence of a D-state component reduces the $B_{\Lambda }$ value. Depending on the strength of the D-state admixture, which we adopt from theoretical predictions or analyses of experimental data, we calculate a reduction of the $B_{\Lambda }$ value of 150–505 keV for the Minnesota ΛN interaction and of 80–270 keV for the effective ΛN force of Yamamoto and Bando.

Resonances may be grouped in families and smear out towards diffractionlike effects: surface waves. Classical Breit-Wigner theory, which is local, cannot describe this evolution from resonances to surface waves. We develop a global theory of resonances, by the use of complex angular momentum plane, which is apt to describe this evolution. Phenomenological examples are taken from ${\pi }^{+}$-p scattering.

The reduced alpha widths of even-even nuclei with N≥84,Z≤84 display a systematic behavior with only few anomalies. The widths were deduced from the known alpha-decay half-lives and branching ratios, with penetration factors calculated from realistic cluster wave functions. Predictions are reported for the half-lives of naturally occurring long-lived nuclei as well as the half-lives and branching ratios of short-lived proton-rich nuclei away from the line of beta stability.

The experimental measurement of the asymmetry parameter of the ${\beta }^{+}$ decay from the $4^{+}$ ground state of ${}_{}{}^{56}{}_{}{}^{}\mathrm{Co}$ to the 2.085 MeV $4^{+}$ state of ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ not only yields a value for the Fermi nuclear matrix element $M_F$, but also has significant Fermi-Gamow-Teller mixing and is of interest for a time-reversal invariance test of the weak interaction. To date, nine such measurements have been made and the values of the $M_F$ fall into two groups: $M_F$∼${10}^{\mathrm{-}5}$ and $M_F$∼(3–5)×${10}^{\mathrm{-}4}$. Our theoretical calculation using the Nilsson model and a one-body spheroidal Coulomb potential yields $M_F$=2.3×${10}^{\mathrm{-}4}$ for β=0.1 and $M_F$=6×${10}^{\mathrm{-}4}$ for β=0.2, which are in reasonable agreement with the experimental values of $M_F$∼(3–5)×${10}^{\mathrm{-}4}$.

The Gamow-Teller transitions $J_i$${=0\mathrm{}}^{+}$ $T_i$=$T_z$=1/2(N-Z)→$J_f$${=1\mathrm{}}^{+}$ $T_f$=$T_z$=[1/2(N-Z)]-1are compared with analogous M1 transitions in which the final states are the same but the initial states have $T_{\mathrm{zi}}$=[1/2(N-Z)]-1. In the single j shell model for the even calcium isotopes, the summed strengths for the analogous M1’s (in Sc) are independent of A, but the corresponding summed Gamow-Teller strength is proportional to (N-Z) and accounts for (j+1)/(3j), i.e., (3/7 of the total ‘‘3(N-Z)’’ sum rule strength. Isospin considerations are exploited as much as possible. It is noted that configuration mixing, e.g., admixtures of j’=l-1/2, lead an enhancement of the low lying strength for the two-particle system ${(}^{42}$Ca), but to a retardation of the low lying strength in the higher A system ${(}^{48}$Ca). An analytic expression is obtained in perturbation theory with a delta residual interaction, to explain this interesting behavior. A brief survey of the experimental situation is made.

Results of shell-model calculations for A=20–28 nuclei are examined for manifestations of collective rotational structure. The calculations use the full set of 0$d_{5/2}$-1$s_{1/2}$-0$d_{3/2}$ configurations and an empirical Hamiltonian which yields a comprehensive reproduction of A=18–38 spectroscopy. The shell-model eigenvalues and the electric quadrupole matrix elements calculated from the shell-model eigenfunctions are treated as pseudodata from which the parameters of the simple rotational model are extracted. These analyses reveal extended groups of model levels in several nuclei which can be characterized in terms of well-defined moments of inertia and stable intrinsic quadrupole deformations. The ‘‘bandlike’’ structure of these groups persists, with diminishing intensity, to the largest values of total angular momentum which can be generated within the sd-shell space for these nuclei. Other sd-shell nuclei which are sometimes considered as ‘‘rotational’’ exhibit some fragmentary evidence for rotational collectivity in the present analyses, but the characteristics of band structure are not sustained over extended sequences of levels.

A scheme for orthogonalizing correlated states while preserving the diagonal matrix elements of the Hamiltonian is developed. Conventional perturbation theory can be used with the orthonormal correlated basis obtained from this scheme. Advantages of using orthonormal correlated states in calculations of the response function and correlation energy are discussed.

A broad based fragmented pattern of the three 2$h_{11/2}$, 1$j_{13/2}$, and 1$k_{17/2}$ unbound shell-model neutron states in ${}_{}{}^{209}{}_{}{}^{}\mathrm{Pb}$ has been obtained on the basis of the recent ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(α${,}^3$He) reaction data. The present theoretical calculation shows that the shell-model energies of the three neutron states lie at 7.8 MeV excitation energy in ${}_{}{}^{209}{}_{}{}^{}\mathrm{Pb}$. The dilution of the neutron strengths of these three high spin states also indicates that the coupling of the neutron particle states with the 11 vibrational states of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ is strong indeed. The theoretical results on the damping of the three neutron states are in sharp contrast with the existing theoretical results on the quasiparticle phonon coupling model calculation.