Form factors for $E1\mathrm{}$ ($\Delta T=0\mathrm{}$) electroexcitation of the 10.8-MeV level of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and the 7.12-MeV level of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ were obtained from inelastic electron scattering experiments. These form factors showed an anomalous $q$ dependence relative to the usual $E1\mathrm{}$ electroexcitation.

The half-lives of several transitions in the ground-state collective bands of ${}_{}{}^{160}{}_{}{}^{}\mathrm{Er}$, ${}_{}{}^{158}{}_{}{}^{}\mathrm{Er}$, and ${}_{}{}^{156}{}_{}{}^{}\mathrm{Er}$ produced by (${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar},4n$) reactions have been measured by a recoil-distance Doppler-shift method. These lifetimes are compared with those of several models. The mean time interval between the reaction and the population of the ground band was also determined.

The intensity of the new microwave radiation observed by Shivanandan, Houck, and Harwit is adequate to produce, by Compton scattering on cosmic-ray electrons, the flux and distribution of ∼100-MeV $\gamma$ rays reported by Clark, Garmire, and Kraushaar.

The photoproduction reaction channel $\gamma n\to p{\pi }^{+}{\pi }^{-}{\pi }^{-}$ is suggested as a means to test whether the $A_1$ and the $B$ mesons are genuine resonances or kinematic effects. Implications for the duality principle are discussed.

Current data on the decay $K^0\to 2\pi$ are used to extend the results of an earlier analysis testing these reactions for $T$ invariance irrespective of $\mathrm{CPT}$ symmetry. The extended analysis together with recent work on pion production data allow us to establish that $T$ is not conserved in these decays.

We show that in some applications of vector-meson dominance to photon reactions in nuclei the mass of the $\rho$ meson cannot be neglected at photon energies of current interest. Thus, in calculation of the photon absorption cross section in the optical-model approximation, the effect of the $\rho$ mass $m_{\rho }$ is important for photon energies $\omega \lesssim m_{\rho }^{}{}_{}{}^2{(\frac{R}{\sigma N)}}^{\frac{1}{2}}$, where $R$ and $N$ are the radius and density of the nucleus, and $\sigma$ is the total $\rho$-nucleon cross section.

Electrons were injected from a 3.3-MeV 300-A accelerator into a circular orbit in a pulsed magnetic field. Trapped ring currents of 150 A were magnetically compressed from 19- to 3.5-cm radius and simultaneously accelerated from 3.3 to 18 MeV. The rms dimensions of the cross section of the ring after compression were $a=2.3\mathrm{}\pm 0.2$ mm radially and $b=1.6\mathrm{}\pm 0.2$ mm axially. The lifetime of the ring, typically 5.5 msec, was determined by the decay of the magnetic field after compression and could be decreased by the addition of hydrogen gas, indicating the focusing effect of the trapped positive ions.

The duality between the $s$- and $t$-channel descriptions of strong-interaction scattering amplitudes and the assumption that in every channel the scattering proceeds via nonexotic resonances are exhibited by simple diagrams. The diagrams lead to simple derivations of some known consequences of these assumptions as well as to many new predictions which can be tested experimentally.

A model of the Pomeranchuk term as a sum over two-body intermediate states is constructed. Experimental tests involving resonance production are suggested.

It is shown that the observed flux of galactic gamma rays, which is one order of magnitude higher than the theoretical value, can be explained if one assumes the recently detected far-infrared radiation to be galactic or universal. Effects of the infrared radiation on cosmic rays are discussed.

It is shown that a class of theories, of which Sugawara's theory of currents and certain Yang-Mills type theories are examples, possess a particular symmetry which is not, even approximately, present in the observed strong interactions. The symmetry would imply that all mesons and all massive fermions have partners with opposite parity and opposite charge conjugation.

We have observed the Hanle effect in the ${}_{}{}^2{}_{}{}^{}\Sigma \mathrm{}(v=0\mathrm{})\mathrm{}$ excited state of the free radical OH in lines which originate from sublevels with rotational quantum numbers $K=3,4,5\mathrm{}$. From the widths of each of these experimental signals we can calculate the $g$-factor-lifetime product and, since the lifetime of the state has been measured previously, our observations yield the values $g[K=3\mathrm{}]=0.176\mathrm{}\left(23\right)\mathrm{}$, $g[K=4\mathrm{}]=0.141\mathrm{}\left(15\right)\mathrm{}$, and $g[K=5\mathrm{}]=0.118\mathrm{}\left(11\right)\mathrm{}$.

By adiabatic compression of a two-phase mixture of liquid and solid ${\mathrm{He}}^3$, temperatures below 2.5 mK have been obtained. These are in the range expected for nuclear ordering in solid ${\mathrm{He}}^3$.

Every scalar-pressure, perfectly conducting, two-dimensional equilibrium with three magnetic field components and an arbitrary pressure profile but no current in the ignorable direction is magnetohydrodynamically stable. The stability of these equilibria bears no visible relation to any magnetic well or average magnetic well criterion and is only partly ascribable to shear.

It is shown that at frequencies approximately equal to one-half the electron cyclotron frequency, the threshold power for the self-focusing of the whistler mode becomes sufficiently small to be available for laboratory experiments.

A theoretical Fermi-surface model is presented for Th. It is in qualitative agreement with the earlier experimental results of Thorsen et al., and with the more recent results of Boyle and Gold as presented in the following Letter. We conclude that Th is very similar to the fcc transition metals.

High-resolution studies of the de Haas-van Alphen effect in thorium, although not yet complete, are found to provide strong support for the validity of a new model for the Fermi surface proposed by Gupta and Loucks in a companion paper.

We report the first use of magnetoplasma effects for phase-matched nonlinear interactions in the far infrared.

After rapid heating of chromium from a temperature between $T_{\mathrm{sf}}$ and $T_{\mathrm{N}}$ to just above $T_{\mathrm{N}}$, a marked lattice relaxation is noticed. The relaxation times and their temperature dependence indicate that the diffusion of interstitital nitrogen-possibly ordered in tetragonal domains below $T_{\mathrm{N}}$- is responsible for the observed effect. In order to explain the macroscopic volume strain associated with nitrogen interstitials it is believed that immediately after heating the nitrogen atoms are accompanied by residual short-range spin ordering and an associated magnetostriction. A model for the formation of domains on cooling past $T_{\mathrm{N}}$ in zero field is proposed.

By means of the reaction ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}\mathrm{}(t,p)\mathrm{}$, we have achieved the first reported production of excited states of ${}_{}{}^{98}{}_{}{}^{}\mathrm{Zr}$. Comparison of the experimental proton angular distributions with the predictions of a distorted-wave calculation has yielded spin and parity assignments for many of the states. Possible identification of neutron configurations with some of the states is discussed.