The interaction between an electron beam and the electric field of a whistler (helicon) wave in a semiconductor (InSb) has been observed. The interaction is of the Landau type and occurs when the wave phase velocity approximately equals the beam velocity.

It has been found that an intense beam of linearly polarized light can induce a magnetic anisotropy in silicon-doped yttrium iron garnet at liquid-helium temperatures. Furthermore, there is associated with this anisotropy a substantial linear dichroism.

Pauling's resonating-bond theory is reformulated in terms of an itinerant dielectric model. In extreme cases discrepancies of more than 200 kcal/mole between the observed cohesive energy and Pauling's value are reduced to 1 kcal/mole. The results completely justify the concept of resonating covalent and ionic contributions to cohesive energies of tetrahedrally coordinated crystals.

An expression is derived for the average reaction cross section using the two-channel, multilevel form of the unitary low-energy scattering matrix. It expresses the average cross section as a function of the transmission coefficients only and is valid for all values of the transmission coefficients. It is shown that over a wide range of the values of the transmission coefficients the values calculated using the Hauser-Feshbach expression agree very well with the present model.

The differential cross section for the photodisintegration of the deuteron has been measured at laboratory photon energies of 222, 254, 302, 342 MeV in steps of 10° between 20° and 160° in the center-of-mass system.

$K^0\text{'}\mathrm{s}$ were produced by the charge exchange of $K^{+}\text{'}\mathrm{s}$ in Cu targets and the subsequent decays observed in a spark chamber situated in a magnetic field. The time distribution of 686 selected events yields $\mathrm{Re}x=0.09\mathrm{}\pm 0.15$, $\mathrm{Im}x=-0.11\mathrm{}\pm 0.11$ if $x$ is allowed to be complex, and $x=0\mathrm{}\pm 0.12$ if $x$ is constrained to be real. Thus, while several previous chamber results seemed to converge on $x\simeq 0.2$ as the most probable value, our data shift somewhat the likelihood distribution in favor of the $\Delta S=\Delta Q$ rule.

Muon inelastic scattering has been measured using muons with momenta between 8.6 and 12.9 GeV/c striking a carbon target. The virtual-photoproduction cross section is presented as a function of the four-momentum transfer from the muon.

We have measured muon bremsstrahlung of 9- to 13-GeV/c muons by using a carbon-plate spark chamber as a target. Our results in the region of invariant four-momenta of the recoil muon-photon system 200-650 MeV/c are consistent with the predictions of quantum electrodynamics.

We have examined all two-body, elastic-scattering amplitudes in quantum electrodynamics. Aside from the photon-pole contribution, the amplitude for any elastic process is imaginary and proportional to $s$ in the limit $s\to \infty$ with $t$ held finite. The coefficients of $s$, to the lowest nonvanishing orders of $e$, can be expressed simply in terms of "impact factors." The results contradict both the Regge-pole model and the droplet model in their most straightforward interpretations.

The Stanford Linear Accelerator Center 40-in. hydrogen bubble chamber was exposed to 4.3-BeV positron-annihilation radiation. Results are presented on reactions containing no neutrals and one neutral particle in the final state. For $\gamma p\to {\rho }^{0}p$ and ${\omega }^{0}p$ we find cross sections of 19.2 ± 1.2 and 2.8 ± 0.5 μb, respectively. Assuming vector dominance, we determine the $V^{0}p$ cross sections. Evidence for other resonant states is presented, in particular ${\Delta }^{++}{V}^0{\pi }^{-}$, where we find $\frac{{\Delta }^{++}{\rho }^0{\pi }^{-}}{{\Delta }^{++}{\omega }^0{\pi }^{-}}$ about 1.5.

A plot of inelastic $\mathrm{pp}$ scattering cross sections is made in terms of the variable $X_{\perp }\equiv \frac{1}{4}{(\beta _1^{}{}_{}{}^{*}+\beta _3^{}{}_{}{}^{*})}^{2}P_{\perp }^{}{}_{}{}^2$, where $\beta _1^{}{}_{}{}^{*}$ and $\beta _3^{}{}_{}{}^{*}$ are the initial and final velocities of the unexcited proton in the center-of-mass system and $P_{\perp }$ is the perpendicular momentum transfer. This plot suggests that the inelastic cross sections depend only on $X_{\perp }$ and have for $X_{\perp }<0.75\mathrm{}$ ${\mathrm{GeV}}^2$ approximately the same $X_{\perp }$ dependence as does the square root of the elastic $\mathrm{pp}$ cross sections.

It has been suggested by several authors that the combination of duality and the Harari-Freund conjecture implies the existence of particles with exotic quantum numbers. We will show that this conclusion can be avoided if we take Regge cuts into account.

Interstellar formaldehyde (${\mathrm{H}}_2$CO) has been detected in absorption against numerous galactic and extragalactic radio sources by means of the $1_{11}$-$1_{10}$ ground-state rotational transition at 4830 MHz. The absorbing regions often correspond in velocity with 18-cm OH features. ${\mathrm{H}}_2$CO is the first organic polyatomic molecule ever detected in the interstellar medium and its widespread distribution indicates that processes of interstellar chemical evolution may be much more complex than previously assumed.

Using $K^0$ produced by $K^{+}$ charge exchange in Be, we have measured the charged-to-neutral branching ratio of $K_1^{}{}_{}{}^0$. We obtain 2.285 ± 0.055 to be compared with the $\left|\Delta I\right|=\frac{1}{2}$ rule prediction of 2.00. This 5-standard-deviation violation gives $\mathrm{Re}\left(\frac{A_2}{A_0}\right)cos({\delta }_2-{\delta }_0)=0.0345\mathrm{}\pm 0.007$.

Using $K^0\text{'}\mathrm{s}$ produced by the charge exchange of $K^{+}$, we have measured the proper-time dependence of the decays $K^0\to {\pi }^0{\pi }^0$. Analysis indicates that a third-quadrant solution for the phase of ${\eta }_{00}$ is unfavored by more than 2 standard deviations. A first-quadrant solution is acceptable.

We present a simple visual form of duality. It can be derived from SU(3) couplings for trajectories and the absence of resonances in most exotic channels, and has many physical implications.

We derive a sum rule relating the electric field gradient at the nucleus to elastic dipole matrix elements. It appears to present a useful alternative to Sternheimer corrections.

Experiments are described in which the nuclear Zeeman temperature $T_n$ and the temperature of the electron dipole-dipole interaction system $T_{\mathrm{int}}$ in a dilute paramagnetic crystal are measured simultaneously. The spin-lattice relaxation times of these two systems turn out to be equal, thus yielding a direct evidence of the strong coupling between these systems.

The effect of electric field strength of the incident wave on the transmission of electromagnetic waves through an anisotropic plasma has been investigated using field strengths of 27.4 to 137 V/m. Near the electron cyclotron frequency increased transmission occurs for the strong field strengths.

A new application of the Bogoliubov inequality to the compressibility of a quantum or classical nonrelativistic one-component many-body system is derived. For a (two-particle) potential $\frac{\lambda }{r^n}$, the inequality can be integrated to give simple, power-law upper and lower bounds on the ground-state energy as a function of the density. Analogous results are also valid at finite temperatures and for Lennard-Jones potentials at high densities.