The interpretation of the narrow boson resonances at 3.1 and 3.7 GeV as charmed quark-antiquark bound states implies the existence of other states. Some of these should be copiously produced in the radiative decays of the 3.7-GeV resonance. We estimate the masses and decay rates of these states and emphasize the importance of $\gamma$-ray spectroscopy.

The discovery of narrow resonances at 3.1 and 3.7 GeV and their interpretation as charmed quark-antiquark bound states suggest additional narrow states between 3.0 and 4.3 GeV. A model which incorporates quark confinement is used to determine the quantum numbers and estimate masses and decay widths of these states. Their existence should be revealed by $\gamma$-ray transitions among them.

Diatomic correlation diagrams are the main basis for the description of heavy-ion collisions. We have constructed the first realistic relativistic many-electron correlation diagrams based on nonrelativistic self-consistent-field, Hartree-Fock calculations of diatomic molecules plus relativistic corrections. We discuss the relativistic influences as well as the many-electron screening effects in the I-Au system with a combined charge of $Z=132\mathrm{}$ as an example.

The hyperfine interval $\Delta \nu$ of the positronium ground state has been measured with significantly improved accuracy. Using a S${\mathrm{F}}_6$ buffer gas we obtain $\Delta \nu =203.3875\mathrm{}\pm 0.0017$ GHz and ${\left(\Delta \nu \right)}^{-1\mathrm{}}\frac{\partial \Delta \nu }{\partial D}=(-8.0\mathrm{}\pm 0.4)\times {10}^{-5\mathrm{}}$ ${\mathrm{amagat}}^{-1\mathrm{}}$. Using a ${\mathrm{N}}_2$ buffer gas we obtain $\Delta \nu =203.3854\mathrm{}\pm 0.0029$ GHz and ${\left(\Delta \nu \right)}^{-1\mathrm{}}\frac{\partial \Delta \nu }{\partial D}=(-2.1\mathrm{}\pm 0.6)\times {10}^{-5\mathrm{}}$ ${\mathrm{amagat}}^{-1\mathrm{}}$. No evidence is found for a quadratic dependence of $\Delta \nu$ on density in either gas.

Precise measurements of density profiles in the system nitroethane + 3-methylpentane near the critical solution point demonstrate that concentration gradients form rapidly, but true equilibrium is not achieved even after long times. The data are in qualitative agreement with computer calculations of the behavior of a critical mixture in a gravitational field which show that the initial gradients form by sedimentation. Thus, effects due to gravity may affect careful experiments in critical mixtures.

We present a density-functional theory, renormalized to account self-consistently for the effects of the zero-point motion of surface modes, for the free surface of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at zero temperature. Although detailed liquid-structure effects are included, no static density oscillations near the free surface are found in contrast to a theory of Regge. For the case of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ bounded by a single hard wall, density oscillations near the wall are obtained.

Doublet II is a noncircular cross-section toroidal device with three magnetic axes. Theoretical considerations show that confinement of plasma in a doublet device might be similar to that of a tokamak with a much stronger toroidal magnetic field. Experiments carried out in Doublet II verify this in that the plasmas are found to have densities, temperatures, $q$ values, and confinement properties close to those of comparable circular-cross-section tokamak plasmas.

Experiments show that the precessional instability predicted and observed in weak electron rings trapped in a magnetic mirror field can be suppressed by adding a sufficiently strong magnetic quadrupole Ioffe field to the basic mirror field. In agreement with a theoretical analysis, the instability ceases when the Ioffe field reaches sufficient strength so that the radial gradient ($\frac{d{B}_t}{d\mathcal{r}}$) of the total magnetic field strength becomes positive.

We present tunneling experiments on Cu: $X$ ($X$ stands for Cr, Fe, or Mn) thin alloy films in superconducting proximity with Pb. For cases of Cr and Mn, with Kondo temperatures $T_{\mathrm{K}}$ lower than the critical temperature $T_c$, we observe an impurity band inside the quasi-BCS gap, in agreement with theoretical predictions. Our results on Cu: Fe ($\frac{T_{\mathrm{K}}}{T_c}\sim 5$) do not show such structure and disagree with theory.

The inverse range of correlation for nearest-neighbor, ferromagnetic, Ising models is shown to vanish continuously as the temperature approaches the critical temperature. An example is also given where this property fails. The critical index obeys $\nu >~\frac{2}{\mathrm{}(d+1\mathrm{})\mathrm{}}$. Attention is drawn to the relevance of continuity to mass renormalizability in Euclidean boson quantum field theory.

We present numerical calculations based on a tight-binding model for the organic conductor tetrathiafulvalene tetracyanoquinodimethane (TTF-TCNQ). The model consists of anisotropic planar TTF and TCNQ bands coupled together by an interplanar transfer integral, which produces a nearly zero-bandgap semiconductor. The calculations are compared with experiments and it is found unlikely that all of the data can be explained simultaneously by a noninteracting electron band structure. We then discuss how many-body effects may affect the model and lead to a metal-insulator transition as observed.

Alfvén-wave resonances are used to measure time decay of the electron-hole drop radius in stressed Ge, and striking new properties of the condensate are observed. Compared to standard results, the drop volume is larger by more than 1000, and the drop lifetime is increased from 40 μsec to over 400 μsec. We believe the long-lived condensate corresponds to low-density Ge $〈111〉$ or Ge $〈110〉$ phases with one or two electron ellipsoids occupied.

The magnetization density induced in palladium by an applied magnetic field was measured by polarized neutron diffraction. The measurements were taken with the sample at 4.2 K in an applied field of 57.2 kOe and include the innermost eleven Bragg reflections. The observed density is contracted by about 15% relative to that calculated for ${\mathrm{Pd}}^{+2\mathrm{}}$ by the Hartree-Fock method, and shows an asphericity similar to that of isoelectronic Ni.

Induced magnetization densities determined from an ab initio augmented-plane-wave wave-function study of Pd metal including local density-of-states effects on the Fermi surface were found to yield a neutron magnetic form factor in excellent agreement with the recent experiments of Cable et al. A remarkable feature of these solid-state spin densities is their spatial localization which is greater than even the very contracted Hartee-Fock density of the free ${\mathrm{Pd}}^{2+}$ ion.

We have extracted the ${\rho }^0$ inclusive cross section from ${\pi }^{+}p$ interactions at 6 and 22 GeV/c as a function of the longitudinal variables $y^{*}$ and $x$, and the transverse momentum $P_T$. The ratio of ${\rho }^0$ to $\pi$ inclusive cross sections is found to be rising linearly with ${P_T}^2$, and at $P_T\simeq 1$ GeV/c the ${\rho }^0$ and ${\pi }^{-}$ inclusive cross sections are equal. The implications of this observation for direct lepton production are discussed.

The experimental upper limit for the diffractive photoproduction of the $\psi \mathrm{}\left(3105\right)\mathrm{}$ is 29 nb, with 90% confidence, at an average photon energy of 18.2 GeV.

In the distribution of rapidity gaps between charged particles produced at 100-400 GeV/c, we find direct evidence for the independent production of clusters with density approximately one per unit of rapidity. This cluster-density measurement and the observed charged-particle density imply that the mean number of charged particles per cluster is about two. Implications of these numbers and techniques for refining them are discussed.

The continuous low-energy electron distributions emitted from $K$ and $L$ atomic shells in a small fraction of ${}_{}{}^{210}{}_{}{}^{}\mathrm{Po}$ $\alpha$ decays have been measured from 6 to 100 keV. The corresponding complementary $\alpha$ satellite continua have been measured. Electron and $\alpha$ shapes agree well, but disagree with all extant predictions. $K$ and $L$ emission probabilities were determined. About 65% of the $L$ (but very few of the $K$) electrons ejected are captured into bound states of the $\alpha$ particle.

The first observation of Lyman-$\alpha$ radiation from positronium is described. Positronium is formed in vacuum by a slow positron beam incident on a solid target. Single photons transmitted through an ≈ 20-Å-wide interference filter peaked near the 2430-Å Lyman-$\alpha$ ($2P\to 1S$) line of positronium are observed in coincidence with the annihilation $\gamma \text{'}\mathrm{s}$ of ground state positronium. The observed intensity corresponds to a production of one positronium "atom" in the excited state for every ${10}^4$ incident positrons.

Analysis of sedimentation in a binary mixutre near a liquid-liquid critical solution point shows that, as a result of the divergence of the sedimentation rate, a density inversion occurs. At high gravitational fields (${10}^5$ normal gravity) the inversion can occur as much as 1-3 K above $T_c$. Turbulence associated with the inversion gives the appearance of phase separation.