We consider a model of $\lambda {\varphi }^4$ field theory in which perturbation theory diverges and analytically continue the energy levels into the complex $\lambda$ plane. Using WKB technique, we determine that the energy levels have an infinite sequence of branch points (where level crossing occurs) with a limit point $a\lambda =0\mathrm{}$. Thus the origin is not an isolated singularity. The resolvent ${\mathrm{}(z-H)\mathrm{}}^{-1\mathrm{}}$ has an infinite sequence of poles with a limit point at $\lambda =0\mathrm{}$.

An explicit model for $\mathrm{CP}$ nonconservation is constructed within the framework of the current-current form of weak interactions, which has $\Delta I=\frac{1}{2}$ for the $\mathrm{CP}$-invariant part of (nonleptonic) $H_w$ with $\left|\Delta S\right|=1\mathrm{}$, violates the $\Delta I=\frac{1}{2}$ rule for the $\mathrm{CP}$-nonconserving part, and has no observable effects of $T$ nonconservation in the leptonic decay modes and the electric dipole moment of the neutron.

The possibility is considered that the charge asymmetries ${\delta }_e$ and ${\delta }_{\mu }$ in the decays $K_L^{}{}_{}{}^0\to {\pi }^{\pm }{e}^{\mp }\nu$ and $K_L^{}{}_{}{}^0\to {\pi }^{\pm }{\mu }^{\mp }\nu$ might turn out to be different. Some implications, including a test of $\mathrm{CPT}$, are pointed out.

A mixing model based on current-field identity is used to evaluate the coupling constant for the off-mass-shell transition $A_1\to \pi$. We find, using either the Weinberg relations and the Kawarabayashi-Suzuki-Riazuddin-Fayyazuddin relation or the Goldberger-Treiman relation, $g_{A_1\pi }=m_{A_1}$. We then estimate the cross section for production of $A_1$ by pions on heavy nuclei with the assumption that diffraction dissociation is the most important mechanism by analogy to ${\rho }^0$ photoproduction.

Molecular mechanisms in liquids, which are responsible for the self-trapping of small-scale filaments of light, have been tested with regard to inertial response. Picosecond light pulses are found to self-trap even in viscous liquids and rigid glass where linear and rotational diffusional motions are frozen out. This and other evidence based on the characteristics of these filaments supports a molecular electronic distortion mechanism.

The static polarizability behavior of the ground-state CO molecule is obtained by ab initio calculations. Single-configuration electronic wave functions are computed using a Hamiltonian which includes the interaction with an external electric field. At fields which approach ionization the polarizability increases markedly, by at least 30%, and cannot be adequately described by the usual multipole expansion.

It was previously shown that at temperatures ≥0.36°K and pressures >12 atm negative ions in He II could be accelerated until they emitted rotons at velocities of about 50 m/sec. We find that at temperatures ≤0.3°K negative ions produce only vortex rings at pressures up to 16 atm.

The profiles of several Raman lines arising from nontotally symmetric molecular vibrations in liquid benzene and carbon tetrachloride were analyzed. That these lines have shown greater intensity in the wings than can be accounted for by a Raman process that involves molecular vibrations alone is interpreted as evidence for time-dependent reorientations of vibrationally excited molecules through small angles in the liquid phase. Data analysis on this basis indicates a weaker rotational coupling between molecules in the ground state than there is between vibrationally excited molecules and those in the ground state.

We have calculated the transport properties of a Fermi liquid by solving certain integral equations originally derived by Abrikosov and Khalatnikov. Their result for the thermal conductivity is found to be a factor of 2 too large, and the numerical agreement between theory and experiment is improved by applying this correction. The expressions for the viscosity and diffusion coefficients are also reduced from those previously accepted, but by less than 25%.

Reflectance of liquid water has been measured between 1050 and 3000 Å by two methods, one with the water in an open dish in equilibrium with its vapor and one with a Ca${\mathrm{F}}_2$ or quartz cell. Real and imaginary parts of the index of refraction and dielectric constant, deduced from the data and Fresnel's equations, suggest an exciton transition at 8.3 eV, an interband transition at 9.6 eV, and a band gap of 9 eV.

In this paper a case will be given for the existence of an excitonic insulating region in semiconductor junctions (either metal-semiconductor or $p-n$ semiconductor).

Pytte and Thomas have predicted that in samples showing the Gunn effect the plasma frequency ${\omega }_p$ will go to zero as the electric field approaches the Gunn threshold. Here we calculate ${\omega }_p$ for GaAs, using a two-valley model, and find that (1) the actual variation with field is somewhat different from that predicted and (2) ${\omega }_p$ will not vanish in samples with carrier concentration greater than about ${10}^{18}$ / ${\mathrm{cm}}^3$.

Far-infrared absorption spectra of solid, enriched orthohydrogen and paradeuterium in the ordered state have been obtained. The observed absorption lines are interpreted as being due to optical phonons associated with the ordered sublattices.

It is found that the knockout-exchange contribution to inelastic-scattering processes is very large in many cases, the exchange being relatively more important for high orbitalangular-momentum transfer. The phases of direct and exchange amplitudes as a function of scattering angle are remarkably close to being the same. Inclusion of exchange in the excitation of the collective $2^{+}$ state in ${}_{}{}^{118}{}_{}{}^{}\mathrm{Sn}$ increases the cross section by a factor of 2 compared with the direct amplitude alone.

Gamma rays from the decay of neutron particle-hole states in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ populated by analog resonances in ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$ have been measured with a Ge(Li) crystal. 12 states are found to have observable ground-state transitions. States at 5.27, 5.50, 5.94, 6.32, 6.49, and 7.09 MeV have been assigned $J^{\pi }=1^{-}$ on the basis of ground-state branching fractions and angular distributions.

The spectroscopic factor dependence of the revised model of Butler et al. for deuteron stripping is examined. It is shown that the factor ${\mathrm{}(1-S)\mathrm{}}^{-2\mathrm{}}$ multiplying the cross section in this model results from an incorrect evaluation of a matrix element. The correct evaluation reduces the revised-model matrix element to the original Tanifuji-Butler result.

The suggestion by Callan and Glashow that there is a new component of cosmic rays comprising stable massive charged particles is examined with respect to present experimental evidence. Direct analysis of particle masses at sea level, the angular distribution of low-energy muons, and the energies of energetic muons at great depths underground all point to the likely nonexistence of these particles, at least to the suggested extent of ${10}^{-3\mathrm{}}$ of the normal primary component.

A sum rule for the nucleon mass is derived in a theory which expresses the energy-momentum tensor in terms of currents. A rough evaluation indicates that it is not inconsistent with experiment.

We discuss interpretation and possible crucial tests of a theory in which the energy-momentum tensor is written in terms of currents.