Micron-sized particles have been accelerated and trapped in stable optical potential wells using only the force of radiation pressure from a continuous laser. It is hypothesized that similar accelerations and trapping are possible with atoms and molecules using laser light tuned to specific optical transitions. The implications for isotope separation and other applications of physical interest are discussed.

The asymmetry and differential cross section for elastic scattering of $K^{+}$ mesons from polarized protons have been measured at meson momenta of 1.54 and 1.71 GeV/c, and these new data have been included in an energy-independent phase-shift analysis. The $P_{\frac{3}{2}}$ wave obtained displays some resonancelike character.

The polarization of protons from the decay of polarized ${\Sigma }^{+}$ hyperons has been measured by scattering the protons in a carbon-plate spark chamber. A sample of 1335 useful scatters gave ${\alpha }_0=-0.98\mathrm{}\pm 0.05$ and ${\varphi }_0=22\mathrm{}°\pm 90°$, where $tan{\varphi }_0=\frac{{\beta }_0}{{\gamma }_0}$. Using the data on ${\Sigma }^{+}\to n{\pi }^{+}$ and ${\Sigma }^{-}\to n{\pi }^{-}$ and fitting to the $\left|\Delta \overrightarrow{\mathrm{I}}\right|=\frac{1}{2}$ rule gave ${\chi }^2=0.3\mathrm{}$ for 2 degrees of freedom.

Experimental information relating to the slope of the elastic proton-proton scattering cross section in the region of $-t=0.15\mathrm{}$ ${(\mathrm{B}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ is reviewed. For proton energies greater than 18 BeV, most of the available data indicate that the slope changes from less than 9.0 ${(\mathrm{B}\mathrm{e}\mathrm{V}/\mathit{c})}^{-2\mathrm{}}$ for $-t>\mathrm{}0.2\mathrm{}$ ${(\mathrm{B}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ to a value greater than 10.0 ${(\mathrm{B}\mathrm{e}\mathrm{V}/\mathit{c})}^{-2\mathrm{}}$ for $-t<\mathrm{}0.15\mathrm{}$ ${(\mathrm{B}\mathrm{e}\mathrm{V}/\mathit{c})}^2$.

The possibility of a violation of the Pomeranchuk theorem, as suggested by recent Serpukhov data, is discussed in terms of Regge singularities. At $t=0\mathrm{}$, a simple Regge pole of odd charge conjugation is required, but for $t\ne 0$, the singularity structure in the $J$ plane must be more complicated.

A simple $s$-channel picture of the dominant non-Pomeranchuk contributions to the $A^{\prime }$ amplitude in $0^{-}$ meson-${\frac{1}{2}}^{+}$-baryon scattering leads to (i) a physical interpretation of the $F$ parameter in Reggeon and tadpole couplings to baryons, and (ii) selection rules for baryon couplings to mesons and baryons.

A procedure for isolating the Pomeranchuk contribution to total cross sections is suggested. Application to the $K^{-}N$ and $\overline{p}N$ systems yields the same value within errors as for the $K^{+}N$ and $\mathrm{pN}$ systems, respectively, in agreement with the Pomeranchuk theorem. For $\pi N$, an asymptotic cross section of ${18.1}_{-1.5\mathrm{}}^{+1.2\mathrm{}}$ mb is obtained.

It is suggested that if the structure function $\nu W_2$ for deep inelastic electron-proton scattering behaves near threshold as $\nu W_2\sim \left(\frac{1}{\omega }\right){(1-\frac{1}{\omega })}^p \mathrm{for} \omega \equiv \frac{2M\nu }{Q^2}\to 1,$ then the elastic electromagnetic form factor of the proton $F_1$ behaves for large momentum transfers as $F_1\left(Q^2\right)\sim {\left(\frac{1}{Q^2}\right)}^{\frac{\mathrm{}(p+1\mathrm{})\mathrm{}}{2}} \mathrm{for} Q^2\to \infty$

The common belief that fermions lying on linear trajectories must have opposite-parity partners is shown to be false. Reggeization of a sequence of positive-parity fermion resonances is carried out in the Van Hove model. As a consequence of the absence of negative-parity states, the partial-wave amplitudes must have a fixed cut in the $J$ plane. This fixed cut, in conjunction with the moving Regge pole, provides a new parametrization for fermion-exchange reactions, which is in qualitative agreement with the data.

We apply the soft-photon theorems of Low, Adler and Dothan, and Burnett and Kroll to the radiative decays $K^{-}\to {\pi }^0{l}^{-}\overline{\nu }\gamma$ and ${\overline{K}}^0\to {\pi }^{+}{l}^{-}\overline{\nu }\gamma$ ($l=e or \mu$) to obtain the leading terms in the respective matrix elements. Numerical results for the photon spectra and for the decay rate (as a function of the minimum photon energy) are given in terms of the conventional $K_{l3\mathrm{}}$ parameters $f_{+}\mathrm{}\left(0\right)\mathrm{}$, $\xi$, ${\lambda }_{+}$, and ${\lambda }_{-}$.

In NaF, NaI, and LiF crystals of modest chemical or isotopic purity, only ballistic and diffusive propagation of heat is observed. In very pure NaF an additional pulse occurs. This pulse shows the behavior of incipient second sound.

Wavelength-modulation spectroscopy is used to obtain the temperature dependence of the reflectivity spectrum for GaAs. Results are given in the regions of the $E_1$ doublet and the major $E_2$ peak at 5, 80, 150, 225, and 300°K. The theoretical temperature dependence in these regions is obtained through use of Debye-Waller factors and thermal expansion coefficients in an empirical pseudopotential calculation of the ${\Lambda }_3-{\Lambda }_1$ and ${\Sigma }_2-{\Sigma }_1$ energy splittings.

Antiferromagnetic resonance truncated by the magnetic spin-flop transition at the thermodynamic critical field has been observed in GdAl${\mathrm{O}}_3$. Because of the new phenomenon of truncation resulting from the finite linewidth of the resonances, the first-order nature of the transition is directly observable and the superheating can be determined quantitatively.

The de Haas-van Alphen effect has been studied in the Kondo system Cu:Cr in magnetic fields up to 55 kG at 1.0 K. In alloys containing ∼30 ppm Cr "beat" minima and shifts of the spin-splitting zeros are observed for several orbits. These observations are explained by supposing the normal spin splitting of the Landau levels to be modified by an antiferromagnetic exchange term, so that the effective $g$ factor becomes $g-\frac{\Delta {\epsilon }_{\mathrm{ex}}}{{\mu }_{\mathrm{B}}H}$.

We have calculated the decay rates of the spin fluctuations in the hydrodynamic region above $T_{\mathrm{N}}$ for the isotropic antiferromagnetic RbMn${\mathrm{F}}_3$. Our results agree in magnitude, temperature dependence, and wave-vector dependence with the experimental values reported by Lau et al.

The lifetime for decay of excited ${\mathrm{Np}}^{238}$ compound nuclei has been determined by measuring the emission distribution of fission fragments from a uranium oxide single crystal bombarded with 10-MeV protons. The proton energy, and with this the compound nuclei excitation energies, were selected to give second-chance fission ${\mathrm{Np}}^{238}$ compound nuclei with lifetimes in the range detectable by this technique.

Schwinger's composite model of hadrons, based on dyons, is formulated as a dyon three-triplet model with the postulated symmetry group SU(3)[electric] ⊗ SU(3)[magnetic]. The hadron spectrum is dominated by the superstrong magnetic-charge exchange forces; we find the first "exotic" states to be in the meson channel of the ($2D2\overline{D}$) system. This model possesses the good features of the quark model and explains its paradoxes.

Measurements are reported on the quenching of metastable hydrogen atoms by helium, neon, argon, ${\mathrm{H}}_2$, and ${\mathrm{N}}_2$, all in the energy range 0.5-4.5 keV. For helium, the measured cross sections are in good agreement with the results of a calculation using the eikonal method. This theoretical treatment leads to the conclusion that polarization of the helium atom is important and that the quenching is not dominated by a single process, such as $2s-2p$ transitions.

An absolute measurement of the electron polarization obtained by photoionization of cesium by circularly polarized light is reported. The measured polarization of 65 ± 15% confirms the prediction made by Fano and the assumptions of Seaton on spin-orbit interaction in photoionization of alkali atoms. They also show that it is possible to construct a photoionization source of polarized electrons without using a polarized atom beam.

It is shown experimentally that the Rayleigh central component of the light scattered by a binary solution is composed of two Lorentzian curves.