The primary neutron-capture $\gamma$ rays emitted in the decay of the 3.4-eV resonance in ${}_{}{}^{147}{}_{}{}^{}\mathrm{Sm}$ have been studied with a Ge(Li) detector and the crystal diffraction neutron monochromator at the Brookhaven high-flux beam reactor. The results obtained complement the average resonance capture studies of Buss and Smither. The spins and parities of levels at 1453.6 and 1663.4 keV are shown to be 2+. The results also indicate previously unreported levels at (1648.6), 1970.9, and 2142.5 keV with spins 2, 3, or 4. The spin of the 3.4-eV resonance is confirmed to be 3-.

Predictions of the Kisslinger and "local" optical models are compared to ${\pi }^{+}-{}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ elastic differential cross sections at 270-MeV lab kinetic energy. With no adjusted parameters, the local potential gives a remarkably good fit to the data.

The pole approximation that Narodetskii introduced into the theory of four-particle scattering is here applied to ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, which is assumed to be composed of four structureless α particles. The binding energy of the excited $0^{+}$ state of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ was calculated by using an Irving variational wave functions for the ground state of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and taking both Yukawa and exponential $\alpha \alpha$ potentials. In the light of earlier theoretical results on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, comparing the present results with experiment suggests that at least for calculation of the bound states, the $\alpha$-particle model of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ is reasonable.

A state at 22.722 ± 0.005-MeV excitation in ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$, with a width of 12.5 ± 2.5 keV, has been observed as a resonance in the ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}+d$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}+\alpha$ reactions. The level is assigned $J^{\pi }=0^{+}$ on the basis of excitation functions for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(\alpha ,{\alpha }_2){}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ measured at various angles and is presumed to be the $T=2\mathrm{}$ state reported at this energy. Several partial widths are obtained.

The cross sections for ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ and ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ produced in fragmentation of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ by protons of 150 and 600 MeV and $\alpha$ particles of 880 MeV have been measured by mass spectrometry. The proton-induced cross sections are significantly larger than previous measurements at 600 MeV. The $\alpha$-induced cross sections are roughly a factor of 2 larger than the proton results. The implications of the new cross sections to the problem of light-element (Li, Be, B) production in cosmic rays are discussed.

Absolute $n-p$ elastic scattering cross sections were measured at 19.5 and 25.1° (lab) for an incident neutron energy of 24 MeV. A liquid scintillator detected both the incident and scattered neutrons. The scatterer was a liquid scintillator also. The c.m. differential cross sections were 31.3 ± 0.5 and 30.7 ± 0.6 mb/sr at c.m. scattering angles of 39.3 and 50.5°, respectively. The present results agree with the cross sections predicted by Hopkins and Breit.

A variational procedure for calculating the two-body $T$ matrix $T_l(p,p^{\prime };s)$ is proposed, and studied numerically for the case of the Reid ${}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}$ soft-core potential. The method is based on a variational principle of the Schwinger type, in which the trial functions are themselves off-energy-shell $T$ matrices with fixed $s$ and $p$ (or fixed $s$ and $p^{\prime }$), which are expressed as linear combinations of a convenient basis set. The variationally calculated $T$ matrix turns out to have the interesting form $T=V+V{G}^{\prime }V$, where $G^{\prime }$ is a finite-rank approximation to the full Green's function, of rank equal to the number of basis functions. It also turns out that for potentials of finite rank the approximation is exact, provided that the space spanned by the basis functions includes the form factors of the potential. Numerical results are given for the Reid potential at energies from -50 to 300 MeV, and show good convergence for both on- and off-shell $T$ matrix elements. The nonvariational estimates obtained directly from the trial functions also converge quite well, but less rapidly than the variational results.

A method based on the JWKB approximation is presented for constructing a local potential from a complete set of complex phase shifts at a single energy. By introducing the Sabatier transformation the problem is reduced to solving an Abel integral equation, the solution of which is closely connected with the potential. The resulting optical potential is uniquely determined in the noncritical domain, and its range of validity is in keeping with the JWKB approximation. A direct connection between the phase shifts and the optical potential is thereby established. The above procedure is tested for the scattering of medium-energy α particles, and it is found to be quite reliable over an angular range encompassing the diffraction region. Possible applications of the above method to the elastic scattering of medium-energy heavy ions are discussed.

A unified analysis of semileptonic weak and electromagnetic interactions in nuclei is applied to the $A=12\mathrm{}$ system. The particle-hole model is used to describe the nuclear dynamics of ${\mathrm{B}}^{12}$, ${\mathrm{C}}^{12}$, and ${\mathrm{N}}^{12}$. Neutrino reaction cross sections are presented for comparison with future experiments.

A semiclassical model has been developed to estimate the attenuation of quasifree scattering in nucleon-deuteron breakup. According to this model the probability that an initial quasifree scattering event undergoes multiple scattering is just the probability that one or the other of the emerging high-energy particles strikes the spectator particle before leaving the volume of space occupied by the target deuteron. The model yields directly a prediction for the probability of such a rescattering for events in which the nucleons in the deuteron are far apart. An approximate form is assumed for the short-range behavior of this rescattering probability. With this approximation the predictions of the model for the peak value of the $D(p,2p)n$ cross section agree well with experiment in the energy range 20-50 MeV and the predicted energy spectrum at $E_p=45\mathrm{}$ MeV agrees with experiment in both size and shape.

We have suggested a three-parameter potential of the form $V=V_{0}cos\left[\frac{5}{2}invtan\right(\frac{r}{h}\left)\right]{(r^2-h^2)}^{-n}$, which gives reasonably good fits to known $N-N$ phase shifts up to 300 MeV.

We consider the effect on the binding energies of ${}_{\Lambda }{}^4{}_{}{}^{}\mathrm{He}-{}_{\Lambda }{}^4{}_{}{}^{}\mathrm{H}$ of inclusion of admixing the $\Sigma$ particle, based on a $\Lambda -N$ potential derived from ${}_{\Lambda }{}^5{}_{}{}^{}\mathrm{He}$. This mixing explains the discrepancy in Coulomb energy of ${}_{\Lambda }{}^4{}_{}{}^{}\mathrm{He}-{}_{\Lambda }{}^4{}_{}{}^{}\mathrm{H}$ and leads to a consistent set of potential parameters.

Total cross sections for collisions between high-energy neutrons and nuclei are calculated by means of the Glauber approximation. Both Woods-Saxon and Gaussian density distributions are assumed for the nuclei. The two distributions yield results which may differ from each other by as much as 15%. For light nuclei harmonic-oscillator wave functions are used. The calculations are compared with measurements for neutron energies above 1 GeV. A simple explanation is given to show why the dependence of the cross sections on the mass number $A$ is greater than $A^{\frac{2}{3}}$. Although the multiple scattering series for a mass-$A$ nucleus contains $A$ terms, it is shown that excellent accuracy is obtained by retaining only approximately $3A^{\frac{1}{3}}$ terms and a geometrical argument leading to this result is given. The ratios of the real to imaginary parts of the hadron-nuclei forward elastic scattering amplitudes are calculated and the decrease of their magnitudes with increasing mass number is explained. The neutron-nuclei data are consistent with little or no regeneration.

The Hartree-Fock (HF) method was used to calculate certain properties of light, spherical nuclei using the Feshbach-Lomon potential as the two-body interaction. It was found that these many-body calculations are extremely sensitive to certain parameters in the interaction which are left arbitrary by the fit to two-body scattering data. A set of values for these parameters was determined such that the results of the HF calculation for ${\mathrm{O}}^{16}$ were reasonable. The binding energies and rms radii of ${\mathrm{He}}^4$, ${\mathrm{Ca}}^{40}$, and ${\mathrm{Ca}}^{48}$ were then calculated and found to compare favorably with similar results using different interactions. A second-order calculation in a rather severely truncated space indicated that perturbation corrections are larger than those obtained with the Tabakin potential.

We show that pion-nucleus total cross sections are sensitive to the assumed off-shell behavior of the pion-nucleon amplitude. Dependence on energy and nucleon number is discussed, as in an energy-dependent effective nuclear radius arising from the $p$-wave pion-nucleon interaction.

The reaction ${}_{}{}^3{}_{}{}^{}\mathrm{He}(p,pd)$ has been studied for recoil momenta of the spectator proton up to 230 MeV/c. The cross section of ${}_{}{}^3{}_{}{}^{}\mathrm{He}(p,2p)$ was measured up to 100 MeV/c. The results are interpreted in terms of the plane-wave impulse approximation and the from factors for ${}_{}{}^3{}_{}{}^{}\mathrm{He}\to \mathrm{dp}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}\to p\left(\mathrm{pn}\right)\mathrm{}$ are compared with a calculation of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ wave function in which the two-nucleon interaction is described by a separable potential which reproduces the lowenergy properties of the two-nucleon system.

Using a removal-time-dependent separation energy, the relationship of nucleon removal energies to observed spectra and single-particle eigenvalues is demonstrated. Three different choices of the nuclear single-particle potential are discussed and the observability of their eigenvalues is explained. It is shown that "observed" spectroscopic factors should vary with energy and that single-particle energies determined by measuring centroids will also vary with incident energy. Possible evidence for these removal-time-dependent effects in ($d,t$) and ($p,2p$) experiments is presented and other experiments are suggested to verify these effects.

The proton and $\gamma$-ray decay of the $T=0\mathrm{}$ level at $E_x=10.81\mathrm{}$ MeV in ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ has been studied with the reactions ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^3{}_{}{}^{}\mathrm{He},p){}_{}{}^{14}{}_{}{}^{}\mathrm{N}\left(p^{\prime }\right){}_{}{}^{13}{}_{}{}^{}\mathrm{C}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$ and ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^3{}_{}{}^{}\mathrm{He},p\gamma ){}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ at an incident ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ energy of 14 MeV. The state was populated in an axially symmetric geometry in which the outgoing reaction protons were detected at 0° to the incident beam direction at the focus of a magnetic spectrometer. Analysis of the decay proton and $\gamma$-ray angular correlations leads to an assignment of $J^{\pi }=5^{+}$ to the 10.81-MeV state. The $\gamma$-ray decay goes entirely to the $J^{\pi }=3^{+}$, $T=0\mathrm{}$ state at $E_x=6.44\mathrm{}$ MeV; the fractional $\gamma$-ray branch of the 10.81-MeV state was measured as $\frac{{\Gamma }_{\gamma }}{{\Gamma }_{\mathrm{total}}}=(4.1\mathrm{}\pm 0.8)\%$.

The mean lives of the three lower levels in ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ have been measured with a new version of the Doppler-shift-attenuation method, using a gas as target and absorber. The reaction was ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}(\alpha ,n){}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ at energies ranging from 5.5 to 8 MeV. The results for the mean lives are the following: ${\tau }_m=50\mathrm{}\pm 4, 116\pm 5, \mathrm{and} 66\pm 4$ psec for the 372-, 593-, and 990-keV levels, respectively. In addition, the relative intensity of $\gamma$ rays from the decay of the ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ levels have been obtained at $E_{\alpha }=8\mathrm{}$ MeV. Electron-conversion measurements have also been carried out for the transitions 372→0 and 593→372 keV, which turn out to be almost pure $M1\mathrm{}$.

The triple-correlation geometry suggested by Goldfarb and Seyler is employed in determining the spins of excited states in ${}_{}{}^{25}{}_{}{}^{}\mathrm{Al}$ by means of the reaction ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}(p,p_1^{\prime }){}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}_{}^{*}{}_{}{}^{}$ (1.37 MeV, $J^{\pi }=2^{+}$). Correlations were measured at 35 laboratory energies between $E_p=3.4\mathrm{}-4.9$ MeV. Excitation functions were measured at five angles for ${}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}(p,p_0)$ and ($p,p_1^{\prime }$) between $E_p=2.5\mathrm{}-5.9$ MeV in 20-keV steps. Nine previously unreported resonances are observed, corresponding to excitation energies in ${}_{}{}^{25}{}_{}{}^{}\mathrm{Al}$; (energy in MeV, tentative $J^{\pi }$ in parentheses) 5.13, 5.58 ($\ge \frac{5}{2}$), 5.76 (${\frac{1}{2}}^{+}$), 6.41 (${\frac{3}{2}}^{-}$), 6.53 ($\ge \frac{5}{2}$), 6.78, 7.02, 7.42, and 7.58.