A gauge theory is outlined in which the existence of the Cabibbo angle $\theta$, leptonic $\mathrm{CP}$-invariance violation, and $\mu -e$ nonuniversality are linked. To $O\left(G\right)\mathrm{}$, the sole source of nonleptonic decays is a neutral current. There is no conflict with present neutrino data. This $\mathrm{CP}$-invariance violation induces only superweak effects in $K$ decays. A strategy for finding $\theta$ is indicated.

An already large yield of neon $K$ x-rays produced by a high-energy (60-80 MeV) stripped argon beam has been observed to undergo a tenfold increase when the projectile charge state is changed from +6 ($2p$ shell full) to ∼ + 14 ($2p$ shell empty). This increase may be understood qualitatively in terms of a transfer of $1s$ neon electrons to the empty $2p$ shell of the more highly stripped ions during collisions. Other possible interpretations are also discussed.

The ratio of the scattering intensity for the $v^{\prime \prime }=1\mathrm{}$ excitation to the elastic scattering intensity at 40° and 80° scattering angles has been determined for 10-90-eV impact energies for electron scattering by CO. These ratio curves exhibit broad peaks near 20-eV impact energy which cannot be accounted for by plane-wave calculations based on potential scattering models. The peaks are indicative of a resonant excitation process (or processes) in the $v^{\prime \prime }=1\mathrm{}$ channel in the range 15-25 eV.

A theory is outlined of the aligning action of sound on nematic liquid crystals. It is based on sound-induced stresses and forces and identifies four contributions to the transverse stress. Formulas for the threshold sound intensities of a few simple deformations are given.

Compressive square-wave pulses are launched in a double-plasma device. Their evolution is interpreted according to the Korteweg—de Vries description of Washimi and Taniuti. Square-wave pulses are an excitation for which an explicit solution of the Schrödinger equation permits an analytical prediction of the number and amplitude of emergent solitons. Bursts of energetic particles (pseudowaves) appear above excitation voltages greater than an electron thermal energy, and may be mistaken for solitons.

We develop expressions for multiple Coulomb scattering losses in magnetic focusing devices containing fully ionized matter in the form of "self-colliding orbits." These relations are directly applicable to "migmacell" and Precetron orbits and are generally applicable to other magnetic confinement devices. Focusing forces have a significant effect over a single-particle orbit. For the case of a "migmacell" as it is visualized, confinement times of the order of 1000 sec are predicted in the absence of other losses.

A new formula is derived which relates changes in electron-phonon coupling strength $\lambda$ to shifts in phonon frequencies. Using this formula, the superconducting transition temperature $T_c$ is discussed for bcc transition metals and rock-salt-structure transition-metal carbides.

By photoconductivity measurements the direct band edge has been located at 2.5 eV. With decreasing temperature this edge shows a blue shift, also below $T_C$. Irradiation at the energies of ${\mathrm{Cr}}^{3+}$ crystal field transitions causes both luminescence and photoconduction. The latter shows a strong magnetic field dependence near $T_C$. An energy-level model for Cd${\mathrm{Cr}}_2$${\mathrm{S}}_4$ is proposed. In the model the energy difference between conduction-and valence-band extrema is considerably smaller (about 1.6 eV) than the optical band gap.

The strongly correlated Hubbard model is shown to be significantly affected by a highlying pole of the $t$ matrix. There are important renormalization effects on the single-particle propagator due to the poles, which are of significance even for low densities. Extreme low densities are treated here.

Low-temperature two-photon measurements on T1C1 are reported. For the first time multiphonon sidebands could be resolved in two-photon absorption. A theoretical explanation of line shape is given based on the assumption of resonant intermediate states. In addition, the puzzling temperature dependence of the band edge in T1C1 is cleared up, $\frac{d{E}_g}{\mathrm{dT}}$ being positive between 20 and 300 K.

The nonpolar optic two-phonon deformation potential is shown to have observable effects on the electronic spectrum. Its value is deduced for InSb.

We present a first-principles, but simplified, calculation of the optic two-phonon deformation potential for Ge. The calculated value is in good agreement with experiment.

We have measured vector analyzing powers in deuteron-proton scattering with polarized deuterons incident at 20 and 30 MeV. Our results are in excellent agreement with very recent three-body calculations which clearly show that the nucleon-nucleon $P$-wave interaction is the dominant cause of the vector polarization in nucleon-deuteron scattering at these energies.

Mathematical formalisms for the separation and solution of the tensor perturbation equations in an empty, diagonal, type-IX space is developed, based upon group-symmetry properties of homogeneous spaces. Numerical results in sampling solutions of the "mixmaster universe" show damping amplitudes of perturbations as the universe expands, a behavior in qualitative accordance with earlier results on the Friedmann universe.

We have measured the ratio of the cross section for $\gamma +n\to {\pi }^0+n$ to the cross section for $\gamma +p\to {\pi }^0+p$ at 4.7 and 8.2 GeV. The measurements were made by detecting the recoil nucleons in coincidence with the decay $\gamma$ rays of the ${\pi }^0$'s produced from a deuterium target. At 4.7 GeV the cross-section ratio, $R\equiv \frac{\sigma (\gamma +n\to {\pi }^0+n)}{\sigma (\gamma +p\to {\pi }^0+p)}$, is less than 1.0 at low $t$, with an indication of a dip at about $t=-0.7\mathrm{}{\left(\frac{\mathrm{GeV}}{c}\right)}^2$, and rises to 1.0 at high $t$. The ratios at the higher energy have less structure and are uniformly closer to 1.0.

Evidence is presented to support the onset, in the $50-300-\frac{\mathrm{GeV}}{c}$ region of incident momentum, of the asymptotic prediction of Koba, Nielsen, and Olesen regarding the scaling behavior of the charged-prong multiplicity distribution in proton-proton collisions. Lower-energy data, typified by data at $19\frac{\mathrm{GeV}}{c}$, are found not to demonstrate this limiting behavior.

In an exposure of the 30-in. hydrogen bubble chamber to a $303-\frac{\mathrm{GeV}}{c}$ proton beam, 2245 interactions have been observed. The measured total cross section is 39.0±1.0 mb and the average charged particle multiplicity $〈n_{\mathrm{ch}}〉=8.86\mathrm{}\pm 0.16$.

A measurement of the magnetic moment of the ${\Xi }^{-}$ hyperon yielded the value ${\mu }_{\Xi }=(-2.2\mathrm{}\pm 0.8){\mu }_N$. The ${\Xi }^{-}$ polarization averaged over the acceptance angle and the four-momenta at which data were taken was $\overline{P}=0.30\mathrm{}\pm 0.05$.

Partial-wave analysis of ${\pi }^{+}+p\to {\pi }^0+{\Delta }^{++}$ at 1820-2090 MeV c.m. energy shows that this reaction is dominated by the $F_{37}\mathrm{}\left(1950\right)\mathrm{}$ resonance decaying to $\Delta \mathrm{}\left(1236\right)\mathrm{}$ with $s$-channel helicity $\frac{3}{2}$. The analysis also gives evidence for $F_{35}\mathrm{}\left(1890\right)\mathrm{}\to \pi +\Delta$ via $F$ wave. The coupling of $F_{37}$ to helicity-$\frac{3}{2}$ states, and the unexpected dominance of $F$- over $P$-wave decay for $F_{35}\mathrm{}\left(1890\right)\mathrm{}$, can both be interpreted as arising from the constraints of $s-t$ channel duality.

A two-step excitation mechanism for a cw ${\mathrm{Ar}}^{+}$ laser is proposed. Population densities for upper and lower laser states are calculated, and compared with experimental results. There exists a very good agreement between these results for states where cascade contributions are small.