A combination of direct (distorted-wave Born-approximation) and resonance scattering terms has been used to represent the reaction ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}(p,p^{\prime })$ to the $2^{+}$ collective excited state in the region of the ${\frac{7}{2}}^{-}$ analog resonance at an incident energy of 10.65 MeV. Fits to on- and off-resonance cross sections and analyzing-power angular distributions have yielded spectroscopic information about the parent state in ${}_{}{}^{125}{}_{}{}^{}\mathrm{Sn}$, represented as single-particle neutron states coupled to the $0^{+}$ ground state and the $2^{+}$ collective core state of ${}_{}{}^{124}{}_{}{}^{}\mathrm{Sn}$.

A locally Lorentz-invariant curved-space theory of gravitation where the local field is a massless, spin-2 field ${{\varphi }_{\mu }}^{\nu }$ of Pauli-Fierz type is presented. In this theory $g_{\mu \nu }$ is no longer the gravitational potential itself but reduces to a functional $g_{\mu \nu }\left({{\varphi }_{\alpha }}^{\beta }\right)$ of ${{\varphi }_{\mu }}^{\nu }$. Several rigorous and a general iteration solution of this type are exhibited. The static central body problem reduces exactly to author's 1958 theory in the special case ${{\varphi }_{\mu }}^{\nu }\to {{\varphi }_0}^0=\varphi$ and ${\partial }^{\mu }{{\varphi }_{\mu }}^{\nu }\to {\partial }^0\varphi =0\mathrm{}$ so that as in that theory the three crucial tests are satisfied.

The magnitude of the polar-vector Cabibbo angle ${\theta }_V$ obtained from $K_{e3\mathrm{}}$ decay has been reevaluated using the Kemmer description of pseudoscalar mesons. We find ${{\theta }_V}^{\left(\mathrm{K}\right)}={0.192}_{+}\pm 0.016$. This compares favorably with the value ${{\theta }_V}^{\beta }={0.188}_{-}\pm 0.007$ obtained for $0^{+}\to 0^{+}\beta$ decays, and thus removes the discrepancy between ${{\theta }_V}^{\left(\beta \right)}$ and the value obtained from the conventional Klein-Gordon $K_{e3\mathrm{}}$ description, ${{\theta }_V}^{(\mathrm{K}-\mathrm{G})}={0.235}_{-}\pm 0.019$. Combining the Kemmer and the $\beta$-decay results leads to a "best" value of ${\theta }_V={0.188}_{+}\pm 0.006$. A new determination of the axial-vector Cabibbo angles ${{\theta }_A}^{\left(\mathrm{K}\right)}$ and ${{\theta }_A}^{(\mathrm{K}-\mathrm{G})}$ is also obtained.

The configuration-interaction method is applied to calculate the dissociation energy of ${{\mathrm{He}}_2}^{+}\left(X^2{{\Sigma }_{\mathrm{u}}}^{+}\right)$, yielding a rigorous lower bound of 2.454 eV and a best value of 2.469 ±0.006 eV. These results are used, in combination with available spectroscopic data on vibrational states of the $A^1{{\Sigma }_u}^{+}$ state of ${\mathrm{He}}_2$, to unequivocally make an assignment of 2.549±0.012 eV for the apparent dissociation energy and to predict a barrier height of 0.080±0.018 eV for this state.

The energy transferred in single-electron-exchange processes in ${\mathrm{Ar}}^{++}$-He and ${\mathrm{Ar}}^{++}$-${\mathrm{D}}_2$ collisions has been experimentally determined for relative kinetic energies below 9 eV. The results confirm the "nearest-resonance" hypothesis for these two representative systems.

A mechanism is proposed for the heating of a plasma with a high-current relativistic electron beam which makes essential use of the plasma return current induced by the beam. From overall energy conservation it is concluded that a large fraction of the beam energy is converted into plasma thermal energy. For reasonable parameters the heating occurs through ion sound turbulence generated by the plasma return current.

Some properties of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on the surface of liquid helium are determined from measurements of the surface and interfacial tension of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixtures. As a mixture approaches phase separation, the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on the surface grows continuously into the upper, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-rich phase. At all temperatures the limit of low surface density is well described by the Andreev model, although there is some evidence for a weak, attractive quasiparticle interaction.

The interaction between unstable waves has been investigated in a beam-plasma system under conditions such that nonlinear wave-particle interactions are negligible. At small wave amplitudes the results can be interpreted in terms of a simple three-wave decay process; at large amplitudes the situation is dominated by multiple wave coupling that leads to generation of satellite waves.

Instability of electrostatic ion shock waves has been induced by producing an inhomogeneity in the plasma ahead of the wave. A process based on nonlocal instability of precursor ions ejected ahead of finite-amplitude waves is proposed. In addition, instabilities of large-amplitude ion-acoustic waves have been observed and are ascribed to a similar process.

The Maki conductivity for a superconductor above $T_c$ is regularized by taking account of fluctuation effects in the impurity vertex correction.

The results of a calculation of the properties of a dirty superconductor near the transition temperature are described. The density of states and conductivity are obtained within an approximation that corresponds to BCS theory above $T_c$. In two dimensions or less no singularity is encountered at $T_c$; instead, the conventional BCS results are obtained for $T\ll T_c$, even though the order parameter is strictly zero. The anomalous contribution to the conductivity reported by Maki is found to be well behaved and finite in the absence of external pair breaking.

We report detailed measurements of the fluctuation conductivity above $T_c$ of one-dimensional aluminum microstrips. These results support a new theory by Patton which apparently resolves the recent puzzle concerning the anomalous contribution to the fluctuation conductivity reported by Maki and Thompson. Comparison of experiment with theory indicates that the samples studied are the first characterized by lifetime effects closely approaching the intrinsic limit for a BCS superconductor.

We propose a semiphenomenological model for the elementary phonon excitations in noncrystalline solids. This model can explain the low-temperature anomalies in the specific heat and thermal conductivity of amorphous materials which have been found in recent experiments.

Strong magnetic circular polarization has been observed in many of the intrinsic recombination transitions from a number of alkali halide crystals. The measured $g$ factors, $g\approx 2$, confirm the assignment that these transitions originate in triplet states of the self-trapped exciton. An analysis based on field-induced mixing of the $B_{2\mathrm{u}}$ and $B_{3\mathrm{u}}$ levels of the zero-field split-triplet state is consistent with the field and temperature dependence data for bromides and iodides.

Absorption spectra of RbI crystals of variable thicknesses were measured by a photoncounting technique. The data suggest that the shape of the knee region following the first exciton peak is largely influenced by surface states. Comparison of absorption spectra for two thicknesses of the same sample indicates that the exciton peak at the leading edge of the knee is obscured in thin crystals by the presence of surface effects, and that the shape of the knee region for crystals less than 800 Å thick is largely determined by surface properties.

The energetics of point-defect formation in ionic crystals based on $V_K+e$ recombination has been investigated in detail. A sequence of [110] replacement collisions involving a neutral halogen atom is energetically possible and leads to the formation of well-separated $F$ and $H$ centers. Zero-point energy vibrational and librational amplitudes may lead to defocusing of the early collisions and to the creation of nearby $F$ and $H$ centers from which subsequently $F^{+}$ centers (vacancies) and $I$ centers (interstitial ions) can be formed. Direct formation of these charged centers by a replacement sequence is not possible.

Although density-dependent Hartree-Fock theory based on a realistic interaction with essentially no free parameters yields satisfactory agreement with elastic electron scattering for reasonably well-closed shell nuclei like ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}$ and ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$, an additional correction arises in the case of an imperfectly closed shell. Inclusion of this correction term in ${}_{}{}^{90}{}_{}{}^{}\mathrm{Zr}$ significantly improves agreement with experimental data.

A rather model-independent separation of direct and compound elastic cross sections has been obtained from the analysis of elastic scattering of polarized protons near the lowest $d_{\frac{5}{2}}$ isobaric analog resonances in ${}_{}{}^{89}{}_{}{}^{}\mathrm{Y}$ and ${}_{}{}^{91}{}_{}{}^{}\mathrm{Nb}$.

Excitation functions and energy-averaged angular distributions have been measured for the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{13}{}_{}{}^{}\mathrm{C},\alpha )$ transitions to the 3.66- and 3.89-MeV states in ${}_{}{}^{21}{}_{}{}^{}\mathrm{Ne}$. The similarities observed between these transitions and the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{12}{}_{}{}^{}\mathrm{C},\alpha )$ transition to the 7.83-MeV $2^{+}$ eight-particle, four-hole state in ${}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ suggest a possible eight-particle, three-hole configuration for the 3.66- and 3.89-MeV states of ${}_{}{}^{21}{}_{}{}^{}\mathrm{Ne}$.

The absorption of stopped negative pions by ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ inducing nucleon pair emission is studied. The three-body final-state scattering includes a two-body residual interaction and an optical potential. We find that agreement of this model with experiment cannot be obtained without including Jastrow-type short-range correlations with dominant momentum components between 0.3 and 0.4 $\frac{\mathrm{GeV}}{}c$.