The pseudoparticle-induced multiquark interaction is shown to produce a spontaneously generated quark mass as calculated by a Hartree-Fock treatment. Hence pseudoparticles lead to a dynamical mechanism for spontaneous breaking of chiral $\mathrm{SU}\mathrm{}\left(N\right)\mathrm{}\otimes \mathrm{SU}\mathrm{}\left(N\right)\mathrm{}$ for $N$ flavors.

Following reports of anomalous dielectron prediction in the mass region near 6 GeV at 400 GeV, we searched for an enhancement in the reaction $e^{+}{e}^{-}\to \mathrm{hadrons}$ and $e^{+}{e}^{-}\to e^{+}{e}^{-}$ at SPEAR in the center-of-mass energy range 5.67-6.43 GeV. The leptonic and hadronic cross sections show no statistically significant peaks. In this mass range, 95% confidence level upper limits for the decay width into electron pairs are less than 200 eV for a narrow resonance which decays predominantly either into hadrons or into electron pairs.

From a forward dispersion relation applied to $p+d$ and $p$+${}_{}{}^3{}_{}{}^{}\mathrm{He}$ scattering amplitudes we obtain accurate empirical values for the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$\mathrm{dp}$ and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$d^{*}p$ coupling constants. The corresponding asymptotic normalization parameters for the $S$-state wave-function component of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ are found to be $C^2({}_{}{}^3{}_{}{}^{}\mathrm{He}, dp)=3.40\mathrm{}\pm 0.20$ and $C^2({}_{}{}^3{}_{}{}^{}\mathrm{He}, d^{*}p)=5.85\mathrm{}\pm 0.25$.

The presence of ${\mathrm{N}}^{-}$ has been confirmed for the first time in electron-impact excitation of nitric oxide and of a mixture of ${\mathrm{N}}_2$ and ${\mathrm{O}}_2$. The appearance potentials indicate $N^{-}\left({}_{}{}^1{}_{}{}^{}D\right)$, without excluding ${\mathrm{N}}^{-}\left({}_{}{}^1{}_{}{}^{}S\right)$.

The interaction of a $\theta$-pinch plasma with cold-material end plugs is investigated with a numerical hydrodynamic and heat flow model. A very appreciable improvement in energy confinement is obtained for the 5-m system considered compared to the same system without plugs. The improvement is due to the elimination of convective energy loss, a reduction of thermal conductive loss when $Z>\mathrm{}1\mathrm{}$ end plugs are used, and some recompression of the plasma by ablated plug material.

Results from the first end-stoppering experiment on a high-energy ($T_i\sim 1.5$ keV, $n\sim {10}^{16}$ ${\mathrm{cm}}^{-3\mathrm{}}$) $\theta$ pinch are reported. The experiment was done with quartz end plugs. The results show that the insertion of the plugs improves plasma stability, reduces particle end loss out of the device, and improves the energy confinement.

We have measured the incidence-angle dependence of the absorption of $p$-polarized and $s$-polarized laser radiation by dense plasmas. A significant absorption peak at nonnormal angles of incidence is observed which is attributed to resonance absorption.

At both the cubic-rhombohedral phase-transition temperature $T_c$ and the zero-gap temperature $T_b$, anomalous increases in Raman intensities are observed in ${\mathrm{Pb}}_{1-x}{\mathrm{Sn}}_x\mathrm{Te}$ (for $x=0-1\mathrm{}$) single crystals. These are attributed to Raman scattering enhanced by the softening of the TO phonon near $T_c$ and also allowed by enhanced interband-mixing effects near $T_b$. These interband-mixing effects not only enhance the Raman intensity, but also increase $T_c$.

Lattice-constant measurements of epitaxial solid krypton monolayers adsorbed on the basal plane of graphite reveal an apparently second- (or higher-) order structural phase transition from an in-registry $(\sqrt{3}\times \sqrt{3})30\mathrm{}°$ structure to an out-of-registry compressed structure. Measurements as a function of equilibrium vapor pressure were made with a high-resolution, low-energy-electron diffraction apparatus for three temperatures near 57 K. Indirect evidence for spatial modulation of the compressed structure by the substrate potential is presented.

Results on the magnetic-field dependence of the order parameter in a nematic single crystal are reported for the first time: The induced birefringence of a nematic single crystal of 4′-$n$-heptyl-4-cyanobiphenyl was found to vary linearly with the magnetic field as predicted by the fluctuation theory.

A new experimental technique, angle-of-incidence modulated surface plasmon resonance, is used for in situ studies on noble-metal films. The method is used to record the real and imaginary parts of the surface-plasmon wave vector and the strength of the surface roughness scattering during room-temperature ${\mathrm{O}}_2$ exposure. The atomic susceptibility of oxygen on Cu at 632.8 nm is found to be ${\chi }_a=(1.2+1.6i)\mathrm{}\times {10}^{-24\mathrm{}}$ ${\mathrm{cm}}^3$. Roughly 0.2% of a monolayer can be detected.

The interaction of electrons and of holes with the two-level tunneling modes appearing in certain amorphous semiconductors is studied theoretically. An electron or a hole can be localized in the vicinity of a tunneling mode; a tunneling mode can also mediate an effective electron-electron or hole-hole attraction which gives rise to localized electron or hole pairs. These electronic states provide a unified explanation for numerous experimentally observed properties, some of which have not been discussed before.

We show that the linear compound Nb${\mathrm{Se}}_3$ becomes superconducting under pressure. We have measured the initial slope of the magnetization of Nb${\mathrm{Se}}_3$ as a function of pressure down to temperatures as low as 50 mK. A very small pressure is necessary in order for the superconductivity to occur. $T_c$ is strongly pressure dependent. We find that the initial slope $\frac{d{T}_c}{\mathrm{dP}}=0.6\mathrm{}$ K/bar. We attribute this huge variation of $T_c$ to changes in the band structure induced by pressure.

The Evans modification of Ziman liquid-metal theory is extended to apply to amorphous and disordered crystalline alloys. In particular, the theory is shown to explain such common behavior of these systems as the change in sign of the temperature coefficient of resistivity with alloy composition, the quadratic temperature dependence of resistivity at low temperature, and the linear temperature dependence of resistivity at high temperatures.

Optically detected electron-spin coherence effects in the photoexcited triplet state of a new defect, the $F_A$-Mo pair in CaO, are presented. They include a Stark-field-stimulated modulation of the Hahn-echo decay.

Self-consistent calculations allowing electron redistribution in a wide region around a Ge-GaAs(110) interface reveal six types of interface states. The charge densities and local density of states at the interface indicate Ge-Ga bonding states in the gap (but below the valence-band maximum) and a variety of other states at lower energy. Some estimates based on these pseudopotential results give information on band-edge discontinuities and the character of bonds across a nonpolar interface.

The charge ratios of muons produced by the interaction of 400-GeV protons with thick copper targets were measured and the +/- ratios were found to be much larger than similar ratios for muons in the secondary cosmic rays. The difference between these charge ratios is taken to indicate that the neutron/proton ratio in the primary cosmic rays is quite large: i.e., of the order of 25:75.

A class of U(1)-invariant theories in $d$ dimensions is introduced on a lattice. These theories are labeled by a simplex number $s$, with $1<~s<d$. The case with $s=1\mathrm{}$ is the $X-Y$ model; and $s=2\mathrm{}$ gives compact photodynamics. An exact duality transformation is applied to show that the U(1)-invariant theory in $d$ dimensions with simplex number $s$ is the same as a similar theory in $d$ dimensions but which is $Z_{\infty }$-invariant and has simplex number $\tilde{s}=d-s$. This dual theory describes the topological excitations of the original theory. These excitations are of dimension $\tilde{s}-1\mathrm{}$.

We have measured the decay rate for ${K_L}^0\to {\mu }^{+}{\mu }^{-}$ in a double-arm spectrometer at the Argonne zero-gradient synchrotron. Sixteen events were found, from which we calculate $\frac{\Gamma ({K_L}^0\to {\mu }^{+}{\mu }^{-})}{\Gamma ({K_L}^0\to {\pi }^{+}{\pi }^{-})}={4.2}_{-0.9\mathrm{}}^{+1.4\mathrm{}}\times {10}^{-6\mathrm{}}$.

In an exposure of the Fermilab 15-ft bubble chamber filled with a heavy neon-hydrogen mixture to a broadband neutrino beam, we have observed 81 dilepton events of the type ${\nu }_{\mu }+\mathrm{Ne}\to {\mu }^{-}+e^{+}+\dots$. This corresponds to (0.5±0.15)% of the total charged-current neutrino interactions. A total of fifteen neutral strange-particle decays (${K_s}^0\to {\pi }^{+}{\pi }^{-}, {\Lambda }^0\to p{\pi }^{-}$) were found in these dilepton events. When corrected for detection efficiencies and unobservable strange particles, this is consistent with the production of approximately one strange particle per event.