The relation between the multiplicity growth and the energy-loss spectrum of an incident particle, as implied by Poisson emission with a classical spectrum, appears to be obeyed experimentally in $\mathrm{pp}$ collisions.

It is shown that present inclusive electroproduction experiments cannot distinguish the fractionally charged quark model from certain multitriplet models with integral charges, e.g., the Han-Nambu three-triplet model, which contain additional internal degrees of freedom and predict new "charmed" hadron states which have not yet been observed. Both models are shown to predict identical results if no "charmed" states are produced, and very similar results unless charmed particle production appreciably affects the inclusive cross section.

Photoproduction of $\varphi$ mesons from hydrogen and carbon was studied at 5.2 GeV by observing $\varphi \to K^{+}{K}^{-}$ decays. The results show that $\varphi$'s are produced diffractively with a $\varphi$-nucleon cross section ${\sigma }_{\varphi N}={9.8}_{-3.3\mathrm{}}^{+2.9\mathrm{}}$ mb. In addition, 80 000 pion pairs were measured to search for the $G$-parity-nonconserving decay $\varphi \to {\pi }^{+}{\pi }^{-}$. Assuming complete interference between $\rho \to {\pi }^{+}{\pi }^{-}$ and $\varphi \to {\pi }^{+}{\pi }^{-}$, we found an upper limit of $\frac{{\Gamma }_{\varphi \to 2\pi }}{{\Gamma }_{\varphi \to \mathrm{all}}}=2.7\mathrm{}\times {10}^{-4}$ at the 95% level.

Large differences have been found in the x-ray yields produced by 22.5- and 48-MeV iodine ions incident on solid (${}_{34}{}^{}{}_{}{}^{}\mathrm{Se}$) and gaseous (${}_{35}{}^{}{}_{}{}^{}\mathrm{Br}$ and ${}_{36}{}^{}{}_{}{}^{}\mathrm{Kr}$) targets. These differences are attributable to the steady-state excitation of the penetrating ion prior to the vacancy producing collision, and yield information on the state of energetic ions in solids.

Mean lives of several levels of the first two ionized states of argon were obtained by Hanle-effect measurements on the fast-beam particles, following coherent alignment of the magnetic substates by beam-foil interaction. The $g$ factors of the levels were obtained by observation of quantum beats. Mean lives are compared with results of the usual beam-foil mean-life measurement technique. We show that the Hanle effect can sometimes clarify beam-foil results.

A model is described for calculating the net current resulting from a 45-kA beam of 3-MeV electrons propagating into neutral nitrogen gas. The model is unique in that it includes the detailed atomic collision processes which determine the return current, and one is able to predict radial, as well as temporal, variations. The results are compared with experiment.

A theory based on roton-roton interaction is developed for the superfluid phase transition in liquid helium. The roton coupling causes a decrease of the roton energy with increasing temperature; thus the roton exhibits a soft-mode behavior, in common with other second-order phase transitions. The calculated superfluid density is in remarkable agreement with experiment, and the roton softening is consistent with recent neutron data.

By means of magnetohydrodynamic approximations, helical equilibrium configurations of current-carrying plasmas housed in a perfectly conducting cylinder were obtained. A particular solution with twisting current channels was obtained at finite amplitude. A small-amplitude equilibrium equation for arbitrary current distributions was also obtained. The presence of magnetic islands in the equilibrium configurations is apparent.

A theory of nonlinear dispersive-wave propagation in inhomogeneous media is used to predict the behavior of a Korteweg-de Vries solitary wave (soliton) incident on a gradient region between two uniform regions. When the gradient induces a transition into an unstable state, the soliton fissions into a train of solitons plus, in general, an oscillatory tail. We derive formulas giving the number and amplitudes of the fission solitons. The theory is applied to surface gravity waves, magnetosonic waves, and ion-acoustic waves.

In two entirely independent experiments we have measured the Rayleight linewidth for S${\mathrm{F}}_6$ on the critical isochore and the results are found to be in strong disagreement with previously reported measurements. Our linewidth data, after subtraction of background terms, exhibit the same critical behavior observed in other fluid systems ($\varphi =0.61\mathrm{}\pm 0.04$). Within the experimental uncertainty our results agree with linewidths calculated from the Kawasaki theory with no adjustable parameters.

We have measured the thermal diffusivity ($D$), the isothermal compressibility (${\kappa }_T$), and the pressure ($P$) along the critical isochore of sulfur hexafluoride over the temperature range $0.048{}_{}{}^{\circ }{}_{}{}^{}\mathrm{K}<(T-T_c)<\mathrm{}2.4\mathrm{}{}_{}{}^{\circ }{}_{}{}^{}\mathrm{K}$. We find that ${\kappa }_T=1.26\mathrm{}\times {10}^{-9\mathrm{}}{\left(\frac{T}{T_c-1\mathrm{}}\right)}^{-1.235 \pm 0.015}$ ${\mathrm{cm}}^2$/dyne and that ${\left(\frac{\partial P}{\partial T}\right)}_V=[7.91+0.18(T-T_c)\pm 0.1]\times {10}^5$ ${\mathrm{d}\mathrm{y}\mathrm{n}\mathrm{e}/\mathrm{c}\mathrm{m}}^2$ deg. We discuss our measurements of $D$ in terms of the Kadanoff-Swift-Kawasaki mode-mode coupling theory.

In the equation of state of a real gas near its critical point the "excluded-volume" effect is taken into account for the droplet-droplet interaction in the droplet model. Considering the hard-sphere repulsion between droplets as a small perturbation ("second virial coefficient") we find the scaling laws to be unchanged. No renormalization of the critical exponents occurs. With an additional attraction between the droplets, the corrections to the asymptotic scaling laws are in agreement with those of Green, Cooper, and Levelt Sengers and Mermin and Rehr.

A phenomenological, charge-conserving, time-dependent Ginzburg-Landau theory is found to lead to a charge density and a difference between the quasiparticle electrochemical potential and the pair electrochemical potential when there is a divergence of the supercurrent. Experimental consequences are discussed.

We have observed critical fluctuations as manifested in paraconductivity above the critical temperature in two immiscible metallic binary liquids, Li-Na and Bi-Ga. The anomaly is of the general form observed in other metallic critical systems. The presence of measurable paraconductivity in these systems and its absence in the Ga-Hg system is attributed to the larger differences in atomic volumes of Li and Na and of Bi and Ga as compared with Ga and Hg.

Electron micrographs have been obtained which clearly show the existence of a void network in amorphous Ge films formed at substrate temperatures of 25 and 150°C, and the absence of a void network in films formed at higher substrate temperatures of 200 and 250°C. These results correlate quite well with density measurements and predictions of void densities by indirect methods.

We investigate the statistical mechanics of a system of localized electrons with a continuous distribution of single-particle energies and interacting with a Coulomb repulsion of the Hubbard form. Among the predictions of this model are a Curie-law magnetic susceptibility, as observed experimentally, and an equilibrium electronic specific heat which is linear in temperature.

The spin-wave spectrum of a one-dimensional Heisenberg antiferromagnet with no long-range order is derived by decoupling Green's-function equations in second order. Results are applied to static correlations, and agreement is obtained with Fisher's classical solution and quasielastic neutron-scattering data in ${\left(\mathrm{C}{\mathrm{D}}_3\right)}_4$NMn${\mathrm{Cl}}_3$.

Neutron-scattering experiments on ${\mathrm{Nb}}_3$Sn show the drastic softening of the [110] acoustic shear modes as well as an unusual frequency response (a central peak in addition to the phonon side bands) near the phase transition at 45°K. A model involving coupling of the bare phonon to other fluctuations with a Debye-like frequency spectrum is proposed which correctly describes the observed cross section as a function of temperature.

Angular distributions for the one-nucleon transfer reactions ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$(${}_{}{}^6{}_{}{}^{}\mathrm{Li}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$)${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$ and ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$(${}_{}{}^6{}_{}{}^{}(\mathrm{L}\mathrm{i}$, ${}_{}{}^7{}_{}{}^{}\mathrm{Be}$)${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$ were investigated at $E\left({}_{}{}^6{}_{}{}^{}\mathrm{Li}\right)=32\mathrm{}$ MeV and were compared with finite-range distorted wave calculations and theoretical spectroscopic factors. These one-nucleon transfer reactions induced by complex nuclei are described by the calculations just as well as those induced by light projectiles. A detailed study of the relative cross sections of the isobaric-spin analog transitions shows deviations from isospin symmetry that are due to Coulomb effects.

Results from even-target (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, $p$) reactions in the Ca—Fe region have been surveyed. It is found that the $0^{+}$ $T_{\mathrm{lower}}$ antianalog states are excited with much less strength than expected from isobaric-spin coupling rules.