It is remarked that the $\mu e$ events as well as the jet structure observed at SPEAR may both have their origin in the pair production and decays of integer-charge quarks.

We report the result of a brief experiment to measure the cross section for photoproduction of $\frac{J}{\psi }\mathrm{}\left(3100\right)\mathrm{}$. At a mean energy of 55 GeV we find this cross section per nucleon to be 37.5 ± 8.2 (statistical) ± 4 (systematic) nb. The result establishes the previously indicated rise in $\frac{J}{\psi }$ photoproduction on protons above 20 GeV and suggests that the rise has occurred by 55 GeV.

We report preliminary results on the production of electron-positron pairs in the mass range 2.5 to 20 GeV in 400-GeV $p$-Be interactions. 27 high-mass events are observed in the mass range 5.5-10.0 GeV corresponding to $\sigma =(1.2\mathrm{}\pm 0.5)\times {10}^{-35\mathrm{}}$ ${\mathrm{cm}}^2$ per nucleon. Clustering of 12 of these events between 5.8 and 6.2 GeV suggests that the data contain a new resonance at 6 GeV.

The $J^P=0^{-}$ partial waves of the $K\pi \pi$ system in the reactions $K^{\pm }p\to K^{\pm }{\pi }^{+}{\pi }^{-}p$ at 13 GeV are presented. Structure in intensities and relative phase variations suggest the existence of a pseudoscalar resonance, the $K^{\prime }$, with a mass of ∼1400 MeV and a width of ∼250 MeV decaying predominantly into $\epsilon K$.

Muon capture rates in nuclei can be accounted for by a simple three-parameter phenomenological formula. I present a microscopic analysis of this formula. Large discrepancies between the unperturbed shell-model results and the phenomenological parameters are found. Considerable improvement is obtained when long-range correlations are introduced. However, it is shown that the calculated total capture rate can be in agreement with experiment but that incompatibilities can still exist in the individual parameters.

The channeling effect has been observed to reduce the ionization energy loss by about a factor of 3 for 1.35-GeV/c protons and ${\pi }^{+}$ traversing a 0.67-mm germanium crystal.

The magnetic and optical properties of all the phases of ${\mathrm{V}}_2$${\mathrm{O}}_3$ show a loss of ${\mathrm{V}}^{3+}$-ion identity. Optical studies of ${\left({\mathrm{V}}_2{\mathrm{O}}_3\right)}_x{\left({\mathrm{Al}}_2{\mathrm{O}}_3\right)}_{1-x}$ reported here show that ${\mathrm{V}}^{3+}$ - ${\mathrm{V}}^{3+}$ interactions between second and further near neighbors are too weak to destroy the ${\mathrm{V}}^{3+}$ identity. This result suggests the possibility that the basic localized-electron unit in the antiferromagnetic insulating phase may be the nearest-neighbor pairs, with the electrons delocalized within a pair.

A magnetic phase transition in a system of loosely coupled antiferromagnetic linear chains is discussed. The low dimensionality of the magnetic lattice gives a large zero-point spin reduction. This large spin reduction strongly influences the field dependence of the sublattice magnetization. Experiments show that the magnitude of the sublattice magnetization depends in a very special way on both applied field and temperature. This is in contrast with a normal three-dimensional antiferromagnet, where the magnitude of the sublattice magnetization is mainly determined by $T$ and not by $H_0$.

The quark-parton model is used to study neutrino scattering in the case where the mass of a heavy, produced quark is not neglected. Evidence for right-handed currents is found in the charged-current neutrino scattering data. The masses of produced heavy quarks are estimated.

We have solved the time-dependent Hartree-Fock equations in three dimensions for the heavy-ion reaction ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ at energies $\frac{E_{\mathrm{lab}}}{A_{\mathrm{proj}}}=8\mathrm{}$, 16, and 24 MeV and impact parameters $b=0\mathrm{}$. 2, 4, 6, and 8 fm. The potential used is a simplified form of the Skyrme interaction. An angular-momentum window for complete fusion is predicted. A multifluid flow pattern similar to that of atomic physics is observed and seems to cast doubts on the validity of the simplified axiality and rigid clutching assumptions currently made.

We have demonstrated a sensitive new method of Doppler-free spectroscopy, monitoring the nonlinear interaction of two monochromatic laser beams in an absorbing gas via changes in light polarization. The signal-to-background ratio can greatly surpass that of saturated absorption. Polarization spectra of the hydrogen Balmer-$\beta$ line, recorded with a cw dye laser, reveal the Stark splitting of single fine-structure components in a Wood discharge.

We report the first experimental determination of the laser "coexistence curve" and "susceptibility" below threshold. Both quantities are derived from an accurate measurement of the average output intensity as a function of the normalized net gain. Our data confirm the predictions of laser theory and give a quantitative support to the recently proposed analogy between the laser near threshold and second-order phase transitions.

We show that our previous exact standing-wave solutions of the Maxwell cold-plasma equations may be generalized to describe partially reflected waves. Using these solutions, we find the transmission and reflection coefficients for intense circularly polarized light incident on a plasma slab.

An ion-acceleration mechanism is proposed in which ions are trapped and accelerated by a negative-energy space-charge wave. Under certain conditions, an electron beam propagating down a slowly converging metal guide can be accelerated. A low-phase-velocity space-charge wave initiated at the large-radius end of the guide, because it is supported by the beam, will also accelerate. By trapping ions in the potential wells of a low-phase-velocity wave, ion acceleration down the converging drift tube can be achieved.

The angular variation of the acceptance of phonons by a cleaved NaF crystal from liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ has been measured as a function of heater temperature and compared with the angular emission through the same interface. There are clearly two channels for transmission in both directions but their dependences on heater temperature are quite different and it appears that the transmission process is asymmetric.

The frequency spectra of anomalous very-low-energy excitations (0-0.3 ${\mathrm{cm}}^{-1\mathrm{}}$) in glasses have been measured by inelastic light scattering for a variety of compositions and temperatures. Possible sources for these spectra include configurational degrees of freedom associated with the low-temperature tunneling states.

A $T_c$-independent graphical analysis of the ultrasonic attenuation in SrTi${\mathrm{O}}_3$ shows evidence for a crossover behavior near the soft-mode transition. This crossover is believed to be from an essentially two-dimensional behavior far from $T_c$ to a three-dimensional behavior very near $T_c$.

The soft-x-ray $L_{2,3}$ emission and absorption spectra of Mg metal have been determined by means of high-resolution ab initio augmented-plane-wave calculations. The inclusion of transition-matrix elements calculated from the augmented-plane-wave wave functions changes the sharp structure found in the joint density of states, yields an $L_{2,3}$ emission spectrum in good agreement with experiment, and indicates that band-structure effects play an important role in the observed x-ray threshold shape.

The Fermi energy as a function of electronic density and temperature is calculated for a defect level in which the effective intrasite electronic correlation energy is negative. It is found that the Fermi level lies below the energy of the highest-filled quasiparticle state, even at $T=0\mathrm{}$, a result which favors $p$-type conduction. Futhermore, the Fermi energy varies only very slowly with electronic density and temperature, and thus is effectively pinned.

The high-frequency conductivity of a two-dimensional electron gas in the presence of ionized impurities is calculated to lowest order in ${\mathcal{r}}_s$. The results for the apparent change in mass with frequency and temperature are directly compared with two sets of experimental data and found to be in excellent agreement with the frequency-dependent results.