The form factor for the stripping distorted-wave Born-approximation amplitude to isobaric analog resonances is derived using a fine-structure theory of these resonances. It is found that the corrections due to compound-nucleus mixing are small. Using the derived form factor, the spectroscopic factors are calculated for the reaction ${\mathrm{Mo}}^{92}({\mathrm{He}}^3, d){\mathrm{Tc}}^{93}$.

The statistical accuracy of earlier results was improved by new measurements on ${\mathrm{Fe}}_{72.5}$ ${\mathrm{Pt}}_{27.5}$ and ${\mathrm{Fe}}_{50}$${\mathrm{Pt}}_{50}$ targets. In reevaluating the data, corrections were made for beam bending and beam shift, and new data regarding the decay scheme of ${}_{}{}^{195}{}_{}{}^{}\mathrm{Pt}$ were taken into account. The $g$ factors of the 211- and 240-keV states of ${}_{}{}^{195}{}_{}{}^{}\mathrm{Pt}$ were found to be 0.104 ± 0.021 and 0.146 ± 0.019, respectively, in disagreement with current theoretical predictions. The value of the hyperfine magnetic field at Pt nuclei in the ${\mathrm{Fe}}_{72.5}$${\mathrm{Pt}}_{27.5}$ alloy is in agreement with static measurements, that for the ${\mathrm{Fe}}_{50}$${\mathrm{Pt}}_{50}$ alloy is -870 ± 60 kG.

Measurements of the angular distributions in the "virtual photon" energy interval of 40 ± 1 MeV and the total cross section in the energy interval of 35.7-49.4 MeV of the ${}_{}{}^4{}_{}{}^{}\mathrm{He}(e, d)e^{\prime }{}_{}{}^2{}_{}{}^{}\mathrm{H}$ reaction are presented. The data are compared with early calculations and with more recent cluster-model and dispersive calculations.

Detailed measurements on the reaction ${\mathrm{B}}^{11}(p, \gamma ){\mathrm{C}}^{12}$ are reported in the incident proton energy range $14\le E_p\le 22$ MeV. Previously reported absolute cross sections for this reaction have been found to be in question. Measurements have been made leading to the first ($2^{+}$) and third ($3^{-}$) states of ${\mathrm{C}}^{12}$ in addition to the ground state. No evidence has been found for the predicted resonance at $E_x=35\mathrm{}$ MeV, also reported in earlier experimental work. Detailed calculations based on the one-particle-one-hole model wave functions of Gillet and Vinh-Mau have been compared with the experimental data using a complete $R$-matrix formalism. Repetition of these calculations using pure $j-j$ configurations yields comparable agreement. Evidence for the importance of many-particle-many-hole configurations in the radiative capture process has been found, particularly in the reaction leading to the first and third excited states, but also in the ground-state reaction data. The calculations are significant in the sense that no new parameters are introduced, nor are any significant approximations used which are not already in the model wave functions under test. The isospin mixing in ${\mathrm{C}}^{12}$ is found to be very small, if the new absolute ($p, {\gamma }_0$) cross section reported here is used; this is in marked contrast to earlier estimates of this mixing.

The polarization $P_{\Lambda }\left(\theta \right)$ and differential cross section $\frac{d\sigma }{d\Omega }$ for $\Lambda$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ scattering are calculated for $\Lambda$ incident energies 5-20 MeV, for the $\Lambda$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ spin-orbit potentials $V_{\mathrm{LS}}$ derived from several one-boson-exchange models given for the $\Lambda N$ interaction in the literature. The $\Lambda$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ central potential used depends on the intrinsic range $b$ for the $\Lambda N$ potential; our knowledge of this parameter is reviewed, and the estimate $b=2.0\mathrm{}\pm 0.3$ fm is obtained for a Gaussian shape from a simplified analysis of the low-energy $\Lambda N$ cross-section data. The effect on $V_{\mathrm{LS}}$ of a cutoff in the $\Lambda N$ spin-orbit potential for distances $r_{\Lambda N}\le d$ is discussed and compared with the regularization adopted in the earlier paper. $P_{\Lambda }\left(\theta \right)$ and $\frac{d\sigma }{d\Omega }$ for the modified $V_{\mathrm{LS}}$ with $d=0.4\mathrm{}$ fm are compared with those for the case $d=0\mathrm{}$; the sensitivity of the largest $p$-wave phase shift and of $P_{\Lambda }\left(\theta \right)$ to the intrinsic range $b$ is also indicated. The relation between these $V_{\mathrm{LS}}$ calculations and the effect of $\Lambda N$ spin-orbit forces in the shell-model analysis of the $\Lambda$ separation energies for the $p$-shell $\Lambda$ hypernuclei is discussed; since the latter prefers $V_{\mathrm{LS}}$ with sign opposite that calculated here, $P_{\Lambda }\left(\theta \right)$ has been calculated also for the spin-orbit potential ($-V_{\mathrm{LS}}$) to illustrate that the sign appropriate for the $\Lambda N$ spin-orbit interaction could be settled by even rough measurements over wide energy and angular intervals in this low-energy region.

A steady-state point of view is used to examine the conditions under which rescattering corrections to the sequential-decay model are important in considering direct reactions to unbound states. Expressions are derived which can give semiquantitative estimates of the size of these effects. A qualitative interpretation is provided for the factors which enter these expressions, and they are evaluated for two specific cases, one where the rescattering effects are expected to be large, and one where they are expected to be small.

The reaction ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}(p, \gamma ){}_{}{}^{15}{}_{}{}^{}\mathrm{O}$ was used to examine the resonance structure in ${}_{}{}^{15}{}_{}{}^{}\mathrm{O}$ between 8.8 and 9.0 MeV. The resonance previously reported at $E_p=1.742\mathrm{}$ MeV was found to have two components corresponding to excitations in ${}_{}{}^{15}{}_{}{}^{}\mathrm{O}$ of 8.920 and 8.925 MeV, respectively. The decay properties of these two levels were studied with high-resolution Ge(Li) detectors, showing that they closely resemble the properties of probable mirror levels at 9.23 and 9.155 MeV in ${}_{}{}^{15}{}_{}{}^{}\mathrm{N}$.

The elastic scattering cross sections of ${\mathrm{Li}}^6$ and ${\mathrm{Li}}^7$ on ${\mathrm{C}}^{12}$ were measured at a number of bombarding energies from 4.5 to 13 MeV. The ratio of the cross section to the Rutherford cross section was determined for a wide range of angles at each energy. The data were fitted by an optical-model potential with four parameters: radius, diffuseness, real well depth, and imaginary surface-absorption well depth. All data for each isotope could be fitted with numerous sets of parameters with real well depths between 40 and 450 MeV. Data for both isotopes could be fitted using the same values for radius and diffuseness and essentially the same for real well depth, but with greater imaginary well depth for ${\mathrm{Li}}^7$. The fit holds good for all energies if a linear dependence of the imaginary well depth on energy is included. Data are also expressed in terms of the nuclear parts of the collision matrix elements which show certain regularities. As a by-product of this work, it was found that in the elastic scattering of lithium by gold the screening of the gold nucleus by its inner electrons is important for energies below 3.0 MeV.

The polarization-transfer coefficients $K_y^y\left(\theta \right)$, $K_x^{x^{\prime }}\left(\theta \right)$, and $K_z^{x^{\prime }}\left(\theta \right)$ in the reaction $\mathrm{T}\mathrm{}(p,n)\mathrm{}{}_{}{}^3{}_{}{}^{}\mathrm{He}$ have been measured for seven laboratory angles between 15 and 120° at $E_p=13.55\mathrm{}$ MeV. At $E_p=8.94\mathrm{}$ MeV, $K_x^{x^{\prime }}\left({30}^{\circ }\right)$ and $K_z^{x^{\prime }}\left({30}^{\circ }\right)$ were determined. In addition, the polarization function, $P\left(\theta \right)$, was measured at 13.55 MeV. The previously reported polarization-transfer data at 0° as a function of energy are given here in more detail. Comparisons are made with $R$-matrix calculations based on the analysis of Werntz and Meyerhof.

Measurements of the Coulomb breakup of ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ have been performed in the energy range of the incident particle from 19-26 MeV. From the analysis of the deuteron component only, an almost constant $B\left(E2\mathrm{}\right)\mathrm{}$ value about 55 $e^2{\mathrm{fm}}^4$ has been deduced.

The elastic scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ from ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ has been measured in the c.m. energy range 13-33 MeV. The measurements include angular distributions at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=21.1,23.7,26.4\mathrm{}$, and 29.0 MeV and excitation functions at ${\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}=50,60,70,80,90\mathrm{}$, and 100°. Data have been analyzed with the conventional optical model with the aid of both strongly and weakly absorbing potentials as well as an absorptive potential obtained from the matter distribution of the colliding ions. The principal result is that the potential must be transparent (weakly absorbing) for surface partial waves. The detailed behavior for the low-$l$ partial waves is not well defined.

Model-independent results, correct to first order in recoil terms $\frac{E}{M}$, are given for various spectrum and correlation effects in allowed $\beta$ decay with parent polarization and/or orientation and for $\beta -\gamma$ circular-polarization correlations.

To investigate the importance of the Pauli exclusion principle in reactions involving multinucleon systems, the problem of deuteron breakup on a recoilless nucleus is considered. Making some simplifying assumptions, we pose a solvable model problem. Then a Hilbert-Schmidt integral equation is obtained for the breakup amplitude, in which the Pauli term is isolated. Corresponding Pauli breakup cross sections are estimated for a model ${\mathrm{O}}^{16}$ target. Interesting features of energy and angular dependence are discussed.

The recent experimental data on the decay of isobaric analog states in ${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$, and ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$ to their low-lying normal-parity states are analyzed. The calculations are carried out in the framework of the Hartree-Fock projection method by considering all the nucleons in the configuration space of the first four major oscillator shells and employing a realistic nucleon-nucleon interaction. It is found that the calculated energy spectrum of ${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$, static moments, and $\Delta T=0\mathrm{}$ electromagnetic transition strengths in these nuclei agree very well with the experimental data. The $\Delta T=1\mathrm{}M1\mathrm{}$ transition strengths and the corresponding $\mathrm{ft}$ values calculated from the projected wave functions are also in good agreement with the experimental observations. The agreement for the $\Delta T=1\mathrm{}$ transitions between the present and the shell-model calculations is found to be nearly as good as that in the case of $\Delta T=0\mathrm{}$ transitions.

The photon spectra following capture of stopped pions in ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$, and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ have been measured for photon energies between 50 and 160 MeV. A pair spectrometer was used and a resolution of 2.0 MeV (full width at half maximum) was achieved. On the basis of several thousand events for each spectrum, we observe collective excitation in the residual nucleus for capture on ${}_{}{}^4{}_{}{}^{}\mathrm{He}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, and ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$. Such excitation is predicted theoretically, and in some cases the detailed comparison with the data is good. For ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ and ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$, no significant structure is seen. In addition, the transition rates to particle-stable states in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ have been measured. A continuum background consistent with a direct-reaction mechanism is also observed for all the elements studied except for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. Results for the pion-capture rates in C${\mathrm{H}}_2$ and ${\mathrm{H}}_2$O are given.

In the cluster model of Brink, Margenau, and Bloch, the motion of two clusters is described by an integral equation for the generator-coordinate amplitude. It is shown that a direct solution of this Hill-Wheeler equation provides a practical framework for the study of cluster-cluster scattering; however, the Coulomb potential is not yet included in the formalism. The case of $\alpha +\alpha$ scattering (with the Coulomb potential neglected) is studied in some detail and dineutron—dineutron scattering is also mentioned.

$\gamma$-vibrational states in the rare-earth region are studied within the framework of the random-phase approximation (RPA), employing the surface $\delta$ interaction as the residual interaction. The calculations are performed without recourse to the schematic model. All terms in the interaction arising in the RPA matrix are taken into account. The results are compared with those obtained considering only the particle-hole term and with experiment. It is seen that previous schematic calculations overestimate the extent of the RPA correlations. Agreement with experiment, however, is not significantly improved.

A search for the $\beta$ decay of ${}_{}{}^{10}{}_{}{}^{}\mathrm{C}$ to the 2155-keV level in ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ has been made in order to test the independent-particle-model predictions using mixed wave functions for the lowest two $J^{\pi }=1^{+}$ levels in ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$. In contrast to a previously reported value of 6.4±2.0×${10}^{-5\mathrm{}}$ per ${}_{}{}^{10}{}_{}{}^{}\mathrm{C}$ decay for this branch, our results limit the strength to ≤8× ${10}^{-6\mathrm{}}$ with 90% confidence, and to ≤4× ${10}^{-6\mathrm{}}$ with 50% confidence. Comparison of this result with the strength of the $M1\mathrm{}$ transition between the 2155- and 1740-keV levels in ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ shows that the ratio of orbital to spin contributions to the $M1\mathrm{}$ matrix element exceeds 3.5. When the Cohen-Kurath wave functions for the first two $J^{\pi }=1^{+}$ levels in ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}$ are mixed in order to fit the strength of the 2155→ 1740-keV $M1\mathrm{}$ transition, the predicted $\beta$ branch to the 2155-keV level is at least 3 times as strong as the present experimental upper limit.

A theory of photonuclear reactions is formulated using a projection-operator formalism. We obtain a $T$ matrix describing a direct photoeffect and a resonance reaction. By introducing doorway and secondary-doorway states, we can conveniently study the structure and energy dependence of the $T$ matrix.

The formalism is applied to the analysis of the photonuclear cross sections of ${\mathrm{O}}^{16}$. The ($\gamma ,n$) and ($\gamma ,p$) cross sections are calculated. We consider those channels in which the residual nucleus is left in the ground state ($J^{\pi }={\frac{1}{2}}^{-}$) or the third excited state ($J^{\pi }={\frac{3}{2}}^{-}$). In the shell-model formulation, the doorways are taken to be mixtures of 1p-1h states, which are constructed in the Tamm-Dancoff approximation. The secondary doorways are assumed to be 3p-3h states, which are constructed in the interacting-boson approximation of Iachello and Feshbach. By mixing the doorways and the secondary doorways, we obtain a microscopic description of the compound states formed in the reactions. The doorways are shown to be responsible for the gross structure of the giant dipole resonances, while their couplings to the secondary doorways give rise to intermediate structure. A particular model of the 3p-3h states, together with certain simplifications in the description of the reaction, reproduces some of the experimental data (the photodisintegration to the $J^{\pi }={\frac{1}{2}}^{-}$ ground state) to a surprising degree of accuracy.

The calculation evidently shows the importance of the 3p-3h admixture in the low-lying odd-parity states of ${\mathrm{O}}^{16}$. Our results also give strong support to assigning $E1\mathrm{}$ nature to the resonances at 21.0, 22.3, 23.1, 24.2, 25.2, and 25.6 MeV.

In an experiment with semiconductor and scintillation counter telescopes we have measured the photodisintegration cross section of ${\mathrm{He}}^3$ at photon energies from 40 to 150 MeV and proton laboratory angles of 30, 60, 90, 120, and 135°.