The cross section for the reaction ${\pi }^{-}p\to \Lambda K^0$ has been measured at nine energies from 790 to 1060 MeV, with a beam resolution of ±1%. The results indicate that a strong, narrow ($\Gamma <~20$ MeV) peak in the cross section lies within the energy bin centered at 893 MeV.

A fully relativistic eikonal expansion is discussed. The connection with the high-energy behavior of elastic scattering, especially for quantum electrodynamics, is examined, and the relevance of the results for Regge asymptotic behavior is investigated.

By including $K_S$ in the background which underlies $K_L$, $S$-matrix unitarity can be used to derive a set of constraints on the partial decay amplitudes of the two resonances. The only constraint which does not explicitly involve the strong-interaction background phases is equivalent to the Bell-Steinberger sum rule.

We show how the usual phenomenological description of the decays of the $K_S$ and $K_L$ mesons can be derived in a unified manner beginning from a description of the $K_S$ and $K_L$ states as overlapping resonances in a scattering matrix. The unitarity relations for overlapping resonances in a $\mathrm{CPT}$-invariant (but not $\mathrm{CP}$- or $T$-invariant) theory play a crucial role in the discussion, and are treated in detail.

The magnetic field dependence of long-wavelength infared laser emission has been studied in ${\mathrm{Pb}}_{1-X}{\mathrm{Sn}}_X\mathrm{Se}$ diodes for compositions in the range $0<~x<~0.3$. For $x>\mathrm{}0.15\mathrm{}$ the energy of the lowest transition decreases with increasing magnetic field whereas for $x<\mathrm{}0.15\mathrm{}$ this energy increases. This unique observation is consistent with a theory of magnetic energy levels proposed by Baraff and also strongly supports the inversion model for the energy bands in Pb-Sn chalcogenides.

Angular distributions of electrons scattering from hydrogen are compared with the predictions of Glauber theory.

A quasiparticle-current-fluctuation contribution to the radiation emitted by Josephson tunnel junctions is calculated. The result is combined with Stephen's result for the pair-current-fluctuation contribution and compared with experimental linewidth data for Sn-I-Sn and Pb-I-Pb junctions.

An experimental study of the electrical resistivity in dilute Cu:Mn doped with Pt impurities is presented. The results indicate a suppression of the Kondo divergence in the conduction-electron scattering amplitude as a result of the spin-orbit interaction at the Pt impurities. The results are interpreted in terms of a reduction in the spin "memory" time.

Measurements of the ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ Knight shift in Au${\mathrm{Al}}_2$, Au${\mathrm{Ga}}_2$, and Au${\mathrm{In}}_2$ are reported. In contrast to the strong temperature dependence of the ${}_{}{}^{71}{}_{}{}^{}\mathrm{Ga}$ Knight shift, only a weak temperature dependence of the ${}_{}{}^{197}{}_{}{}^{}\mathrm{Au}$ Knight shift in Au${\mathrm{Ga}}_2$ is observed. Electronic energy-band calculations for these compounds yield differences which provide an improved model for interpreting these and other experimental results.

The two-photon absorption spectrum of KI has been measured to 7.5 eV. The region studied spans the spectral range in which all the prominent one-photon absorption peaks reside. Our two-photon data exhibit two noticeable peaks at 7.21 and 7.375 eV. Based on the parity argument and polarization dependence, we tentatively assign the peak at 7.21 eV to a ${\Delta }_6\to {\Delta }_6$ transition.

Exciton spectra of crystalline CaO and MgO at 25°K are presented and interpreted in terms of valence-band spin-orbit splitting and strong exciton-phonon coupling.

We have investigated the phonon avalanche in Ce-doped lanthanum magnesium double nitrate using pulsed microwave and pulsed magnetic-field techniques. In these experiments we have been able to determine the lifetime of the avalanche phonons and to obtain some evidence for coherence in the spin-phonon interaction.

Striking evidence for a fundamental covalent-ionic transition in the electronic nature of solids is presented.

Crystal distortions in Cr associated with antiferromagnetic ordering have been established using electrical-resistance strain gauges. Between 123 and 311°K the observations confirm the existence of an orthorhombic structure associated with the presence of a transversely polarized spin-density wave.

We describe a promising method for investigating the parentage of nuclear states. It involves the simultaneous observation of ($p,t$) and ($p,{}_{}{}^3{}_{}{}^{}\mathrm{He}$) reactions on $0^{+}$ ($T>\mathrm{}0\mathrm{}$) targets producing analog final states with the same isospin as the target. Experimental results for $20<~A<~36$ ($T=1\mathrm{}$) reveal a number of states with apparently very simple parentage for which $j^2$ "paired" pickup predominates.

We show that if one assumes (following Cowsik and Pal and Shen in their explanation of the flux of galactic gamma rays) that the recently measured far-infrared radiation is galactic, then one must also accept the existence of the x-ray flux, with a magnitude in agreement with observations but with a large anisotropy, in sharp disagreement with the measured isotropy.

An experiment was performed which placed an upper limit of 0.3 Hz on the gravity shift of the proton Larmor frequency rather than 31 ± 10 Hz as reported in the literature.

It is shown that by coupling the gauge fields to a multiplet of scalar fields it is possible to construct a gauge-invariant mass term for the gauge fields.

Consideration of cosmic-ray propagation leads naturally to an equilibrium model for cosmic-ray origin and storage in the galaxy. In this model the relative abundances of nuclei with substantially different charge values are nearly energy independent. We conclude that this simple, one-"component" model is consistent with observations of both the galactic primary (i.e., ${\mathrm{H}}^1$, ${\mathrm{He}}^4$, C, N, O, Fe) and secondary particles (${\mathrm{He}}^3$, Li, Be, B).

The hyperon-nucleon scattering is described by a potential model. The ${\Sigma }^{+}p$ scattering data require a ${}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$ resonance in the $\Lambda p$ scattering, for which resonance there seems to be experimental evidence. Its position and the ${\Sigma }^{+}p$ scattering data determine the ${\Sigma }^{+}p$ effective-range parameters, and combined with the $\Lambda p$ scattering data it determines the $\Lambda p$ effective-range parameters.