An experiment designed to measure the branching ratio of the phi meson to $e^{+}{e}^{-}$ was performed at DESY by measuring phi production and phi decay to $e^{+}{e}^{-}$ with the same apparatus. The results of this experiment, based on ${10}^4$ $\varphi \to K^{+}{K}^{-}$ events and 41 $\varphi \to e^{+}{e}^{-}$ events on carbon, yield a branching ratio of (2.9±0.8)×${10}^{-4\mathrm{}}$. This result is compared with various theoretical predictions.

It is suggested that bond alternation in long conjugated carbon chains is due to an Overhauser charge-density wave in the $\pi$-electron assembly.

Measurements of the ionization losses of 10.0- to 30-keV ${\mathrm{Ge}}^{72*}$ atoms in germanium show no evidence for a cutoff for particle energies less than 23 keV, as might be expected from adiabatic arguments concerning the effect of an energy gap in germanium. The ionization loss is consistent with Lindhard's conjecture that the electronic stopping power of heavy particles is proportional to the particle velocity even at energies far less than this cutoff energy. Any effective energy gap encountered by the germanium atoms moving in a germanium crystal is less than ∼0.1-0.2 eV.

Sparks produced by focusing the beam from a single-mode ruby laser have been investigated, and photographs of radiation scattered at 90° to the incident beam show that breakdown occurs in filaments or points having a diameter of 5 μ or less. Intense pulses of coherent radiation scattered in the forward direction have also been observed, and the measured divergence of this light indicates the presence of self-focused regions having a diameter of ∼1.7 μ. These observations support the hypothesis that self-focusing of the beam may initiate laser-induced breakdown.

A 6-cm-diam, 3-keV ring of approximately ${10}^{10}$ electrons is trapped in a pulsed magnetic mirror field when the midplane field is 60 G. The midplane field rises to 15 kG in 1.0 msec, and the ring is compressed adiabatically to a mean energy of 0.5 MeV. The ring remains trapped for more than 10 msec without observable loss of electrons.

It is shown that in the presence of relative streaming motion, linearly polarized electromagnetic waves of frequencies below the plasma frequency can propagate across the magnetic field. An instability criterion is given for this "modified ordinary mode."

We have used molecular-dynamic techniques on bulk crystals and particles several atom-layers thick to study phonon behavior. It is found that the surface modes in the small particles produce changes in the phonon spectrum quantitatively large enough to explain the observation by Strongin and co-workers of large increases in the superconducting transition temperature of extremely thin films.

Photoemission of holes from various metals into the organic polymer poly-N-vinyl-carbazole has been observed. The photoemission threshold was measured to be 1.28 eV for Au, 1.48 eV for Cu, and 1.53 eV for Al. The position of the valence-band edge relative to the vacuum level is calculated to be 6.1 ± 0.4 eV. A periodic fine structure in the spectral dependence of the quantum yield is attributed to the splitting of the electronic energy levels by molecular vibrations.

Anomalous behavior of the Hall coefficient and the transverse magnetoresistance was observed at liquid-He temperatures in $\beta$-NiA1 which is nonmagnetic and a Hume-Rothery $\frac{3}{2}$ electron compound. A brief discussion is presented.

A rapid and reversible transition between a highly resistive and conductive state effected by an electric field, which we have observed in various types of disordered semiconducting material, is described in detail. The switching parameters and chemical composition of a typical material are presented, and microscopic mechanisms for the conduction phenomena are suggested.

The anharmonicity associated with a lattice resonant mode has been identified by means of a second-order Stark-effect measurement.

Resonance structure iobserved in many ($d,p$) and ($p,d$) excitation functions in the lead region. The results are compared with previously reported ($t,p$), ($p,t$), and ($d,p$) data, and systematic resonance behavior is found common to all stripping and pickup reactions involving incident or final protons. Resonances occur whenever the protonchannel energies lie between 16 and 18 MeV. This is the energy region where single-particle isobaric analog states occur in the reaction ${\mathrm{Pb}}^{208}\mathrm{}(p,p)\mathrm{}$.

We have carried out far-infrared rocket observations in the spectral range from 0.4 to 1.3 mm and have detected a flux of 5 × ${10}^{-9\mathrm{}}$ W${/\mathrm{c}\mathrm{m}}^{-2\mathrm{}}$ sr, with an uncertainty of a factor of 2. The flux is nearly two orders of magnitude greater than that to be expected from a 3°K black cosmic background in this spectral range; its equivalent blackbody temperature would correspond to 8.3°${\mathrm{K}}_{-1.3\mathrm{}}^{+2.2\mathrm{}}$°K.

Preliminary results of an experiment on double-pion photoproduction with spark chamber and counter techniques below 1 GeV are reported. Proton angular and ($p,{\pi }^{+}$) invariant-mass distributions at fixed ${\pi }^{-}$ momentum are given. Comparison with the expected values computed by the isobaric model are shown.

It is shown that the local current algebra of charge densities is inconsistent with a recent proposal for modifying the Adler-Fubini sum rule.

The temperature dependence of the mobility $\mu$ of a heavy impurity in a interacting Fermi liquid is found to be of the form $\frac{1}{\mu }=A+B{T}^2\ln \left(\frac{1}{T}\right)+O\left(T^2\right)$ for low $T$. The coefficients are calculated for the case of a large, hard-sphere impurity. The result is in qualitative agreement with recent experimental data for negative ions in ${\mathrm{He}}^3$.

We report the absorption spectrum of AgCl sheet single crystals up to photon energies of about 5.5 eV. The present results do not confirm the existence of the peak reported in the literature previously and currently attributed to direct excitons. Instead, a structure similar to that already known to be present in the "tail" of the fundamental absorption of large AgCl single crystals is also found at energies up to about 4.1 eV.

We have used electron tunneling to determine the longitudinal optical (LO) phonons in thin films of CdS, CdO, Zns, and ZnO. The II-VI compounds were used as a tunneling barrier separating two metal films, and in some instances they were no more than 10-30 Å thick. The LO-phonon energies obtained in the various compounds agree very well with the values that have been obtained from Raman scattering and infrared spectroscopy on bulk materials.

The elastic scattering of low-energy electrons from Ni is examined at temperatures where the multiphonon scattering is dominant. The effective atomic-scattering factor is extracted. The specularly reflected intensity is examined and the corrections necessary to determine the rigid-lattice interference function are discussed.

Inelastic electron scattering experiments from ${\mathrm{Ca}}^{40}$ and ${\mathrm{Ca}}^{48}$ at 282.8-MeV incident energy indicate the presence of sharp rises in cross section corresponding to the thresholds of the states ${\mathrm{Ca}}^{39}+n$ and ${\mathrm{Ca}}^{47}+n$.