It is shown, contrary to previous work, that in the presence of large shear ($\frac{L_S}{R_P}<\frac{R_P}{a_i}$) an unstable universal eigenmode exists. The criterion for the stabilization of this mode for long wavelengths ($k_{\perp }{a}_i\lesssim 1$) is $\frac{L_S}{R_P}<{\left(\frac{M}{m}\right)}^{\frac{1}{3}}$ which is more restrictive than the usual criterion for stabilization of the transient (convective) modes ordinarily considered.

Measurements of the attenuation and velocity of megahertz longitudinal-acoustic waves have been made near the magnetic critical point of nickel. The temperatures of the attenuation maxima and velocity minima occur below $T_C$ and are frequency dependent. These phenomena, which have not been observed previously in a magnetic system, show striking similarities to the behavior of first sound near the $\lambda$ point of liquid helium.

Photoemission measurements on the magnetic semiconductors EuO, EuS, and EuSe show emission from $4f^7$ states which lie in the gap above the top of ∼2- to 3-eV-wide valence bands. These measurements, together with optical data, indicate semiconductor energy gaps of 4.3, 3.1, and 3.1 eV for EuO, EuS, and EuSe (all ±0.4 eV). Metallic GdS shows a narrow occupied conduction band at the Fermi level, in addition to a filled valence band and $4f^7$ state.

The Josephson frequency-voltage relation has been compared at frequencies of 9.48 and 891 GHz using radiation-induced steps. The results indicate that the relation is frequency independent over this range within an uncertainty of approximately 1.5 ppm.

Low-temperature (1.3-4.0°K) nuclear resonance shifts and spin-lattice relaxation rates of dilute "nonmagnetic" ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$, ${}_{}{}^{53}{}_{}{}^{}\mathrm{Cr}$, and ${}_{}{}^{55}{}_{}{}^{}\mathrm{Mn}$ impurities in aluminum are compared against similar data for the "magnetic" alloys Au: ${}_{}{}^{51}{}_{}{}^{}\mathrm{V}$ and Mo: ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$. It is shown that no essential differences exist between the two types of alloy systems.

A measurement of the electrical and thermal magnetoresistance of thallium gives a direct demonstration of the scattering of open-orbit electrons into adjacent closed orbits through the mechanism of small-angle scattering. Potentially, this effect provides a method for determining the efficiency of small-angle scattering in metallic conduction.

We report observation and measurement of the Zeeman effect of a $P$ state of a bound conduction electron in AgBr. The Zeeman mass which we observe is ∼19% greater than the low-frequency cyclotron mass. This mass shift can be understood quantitatively as a new polaron self-energy effect.

The magnetic dipole gamma-ray strength function for some strongly deformed heavy nuclei is computed on the basis of the Nilsson model, pairing, and a residual spin-spin interaction. The strength of the spin-spin interaction is adjusted to give average agreement with experiment of effective spin $g$ factors for low-energy $M1\mathrm{}$ transitions and moments. Predictions are made for average $M1\mathrm{}$ widths of primary transitions following neutron capture; the predictions are in reasonable agreement with recent data.

We have solved analytically for the acceleration of plasma away from a rotating magnetized object. Application of that analysis to rotator models for the radio, optical, and x-ray pulsar NP0532 suggests that it has a magnetic moment of order 3×${10}^{28}$ G ${\mathrm{cm}}^3$ and is losing mass at a rate order 2×${10}^9$ g/sec. These parameters would provide particles in excess of ${10}^{11}$ eV and a 6×${10}^{-4\mathrm{}}$-G field in the Crab Nebula at 1 lt yr from NPO532.

In a 540 000-frame stopping-$K^{-}$ exposure at the Brookhaven National Laboratory alternating-gradient synchrotron, the branching ratio $\frac{\Gamma ({\Sigma }^{-}\to n{\mu }^{-}\nu )}{\Gamma ({\Sigma }^{-}\to \mathrm{all})}$ is found to be (0.43±0.09)×${10}^{-3\mathrm{}}$. Combining this with the world-average ${\Sigma }^{-}\to n{e}^{-}\nu$ branching ratio of (1.10±0.05)×${10}^{-3\mathrm{}}$ gives $\frac{{\Gamma }_{\mu }}{{\Gamma }_e}=0.39\mathrm{}\pm 0.08$, which agrees with the universal $V-A$ prediction of 0.45.

The capture rate of solar neutrinos is estimated for a number of targets that have been suggested previously as possible detectors of solar neutrinos. It is shown that the most important feasible experiment to be carried out in the future employs ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ as a detector.

We find that absorptive corrections to production amplitudes can generate, through unitarity, absorptive corrections to two-body amplitudes.

Formulas are derived for two new Veneziano-type five-point functions which may be appropriate for processes involving particles of certain quantum numbers.

Using the multiperipheral integral equation in a factorizable approximation, we construct a simple model in which Regge poles and cuts can be studied. In a one-pole version we are able to obtain a bootstrap of a Regge trajectory and residue function. In a two-pole version we obtain a formula in which the amplitude consists of a Regge pole plus the Amati-Fubini-Stanghellini cut.

Forward dips and peaks in $\pi$-exchange differential cross sections are analyzed from the $t$- and $s$-channel points of view. Simple criteria for the presence of forward structures are given. They lead, among other things, to the prediction that $\frac{d\sigma ({\pi }^{-}p\to {{\rho }_{\mathrm{tr}}}^{0}n)}{\mathrm{dt}}$, where "tr" denotes transverse polarization, does not have a forward peak with a width of ${m_{\pi }}^2$, contrary to expectations based on vector dominance.

A qualitative understanding of the observed pattern of Regge trajectories is obtained from approximate duality.

We show that to first order in $\alpha$, and with neglect of effects which vanish in the limit of zero lepton momenta, the theoretical $\mathrm{ft}$ value in 0 → 0 Fermi transitions is independent of $Z$. The only model-dependent feature of this argument is in the treatment of effects induced by the axial current. It is further shown that in higher order radiative corrections the power of $Z$ cannot exceed the power of $\alpha$; the leading term in the radiative correction to the $\mathrm{ft}$ value is therefore of order $Z^2{\alpha }^2$.

Inelastic-energy-loss distributions for single collisions of ${\mathrm{Al}}^{+}$, ${\mathrm{P}}^{+}$, ${\mathrm{S}}^{+}$, ${\mathrm{Cl}}^{+}$, ${\mathrm{K}}^{+}$, and ${\mathrm{Mn}}^{+}$ with argon at keV energies have a triple-peaked structure in a limited range of ${\mathcal{r}}_0$ similar to that observed earlier for the homonuclear case ${\mathrm{Ar}}^{+}$ on Ar. In contrast to the homonuclear case, however, the inner-shell excitation for the asymmetric cases takes place almost exclusively in the one of the collision partners with lowest atomic number $Z$.

Measurements of the time-dependent correlation function for small-angle scattering of visible light by the interface in a fluid mixture to within 3×${10}^{-3\mathrm{}}$°K of its critical temperature $T_c$ have revealed thermal excitations with exponential relaxation times $\tau$ up to about 20 sec. Analysis has shown that $\tau$ varies inversely as the wave number $Q$ and diverges on approaching the critical temperature as ${(1-\frac{T}{T_c})}^{-1.27\mathrm{}}$. Identification of $\tau$ with viscous damping of hydrodynamic waves on the interface permits determination of the critical behavior of the shear viscosity which is found to be at most only weakly divergent.

An experimental method of perturbation about a nonlinear equilibrium state is employed to examine linear growth rates and nonlinear saturation coefficients. This procedure is illustrated by the experimental investigation of finite-amplitude unstable-collisional drift waves in a highly ionized plasma. Preliminary experimental results are compared with existing linear and nonlinear theories.