The ${\Sigma }^{+}$ magnetic moment is measured to be $(2.38\mathrm{}\pm 0.02){\mu }_N$ with use of 44 457 polarized ${\Sigma }^{+}\to p{\pi }^0$ decays in a charged hyperon beam. The inclusively produced ${\Sigma }^{+}$ in this 210-GeV/c beam have a polarization of about 0.20 for production angles between 2.5 and 7.0 mrad.

Single-jet events opposite to an electron track at the proton-antiproton collider may signal the semileptonic decay $\tilde{q}\to e\tilde{\nu }X$ of a heavy scalar quark $\tilde{q}$ with $m_{\tilde{q}}=35\mathrm{}$ GeV. Only an observation of the opposite anti-scalar-quark or gluino jet with its typical missing-energy pattern can distinguish this possibility from the recently suggested top-quark interpretation of the "electron plus single-jet" events. The nonobservation of the hadronic opposite-side jet, for the experimental cut ${E_T}^{\mathrm{jet}}>10\mathrm{}$ GeV, favors a missing-energy signature as expected for supersymmetric particles.

The authors have run computer simulations of the quark and gluon internal energies in SU(3) lattice gauge theory neglecting dynamical fermion loops. At the first-order deconfinement-chiral symmetry restoration transition the internal energies display large discontinuities. With finite-size effects estimated by a procedure suggested by the Bielefeld group, the total latent heat per unit volume is found to be roughly 1.50±0.50 GeV/${\mathrm{fm}}^3$, if the transition temperature is 190±20 MeV. Timing estimates for fermion computer simulation methods are presented.

Six rotational bands have been found in ${}_{39}{}^{99}{}_{}{}^{}\mathrm{Y}_{60}^{}{}_{}{}^{}$, ${}_{39}{}^{101}{}_{}{}^{}\mathrm{Y}_{62}^{}{}_{}{}^{}$, ${}_{38}{}^{99}{}_{}{}^{}\mathrm{Sr}_{61}^{}{}_{}{}^{}$, and ${}_{40}{}^{101}{}_{}{}^{}\mathrm{Zr}_{61}^{}{}_{}{}^{}$. All bands have small and very similar values of $\frac{{\hslash }^2}{2\mathcal{I}}$ that indicate deformations of ∼ 0.3-0.4 and imply that these nuclei are among the most deformed known, with $\mathcal{I}\sim 0.8{\mathcal{I}}_{\mathrm{rigid}}$. Relative strengths of intraband $\gamma$ transitions suggest Nilsson orbital assignments of $\pi \frac{5}{2}\mathrm{}\left[422\right]\mathrm{}$ for the Y ground bands.

Angular distributions of the reaction ${}_{}{}^2{}_{}{}^{}\mathrm{H}(p,\gamma ){}_{}{}^3{}_{}{}^{}\mathrm{He}$ have been measured for $E_p$ from 6.5 to 16 MeV. A comparison of the extracted $a_2$ coefficients with an effective two-body direct calculation indicates a sensitivity to the inclusion of $D$-state components in the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ wave function. These calculations use ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ bound-state wave functions generated from Faddeev-type equations. The theoretical three-body ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ ground-state wave functions having $D$-state probabilities of 5%-9% ($D_2=-0.224\mathrm{} \mathrm{to} -0.236\mathrm{}$) are consistent with the present data.

High-resolution total reaction excitation functions for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$+ ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and detailed angular distributions for the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({}_{}{}^{16}{}_{}{}^{}\mathrm{O},\alpha ){}_{}{}^{24}{}_{}{}^{}\mathrm{Mg}$ have been measured. The interplay between (fifteen) resonance amplitudes and $l$-window (background) amplitudes is emphasized. Spin assignments, obtained from the ${\alpha }_0$ data, are dominated by values of $8\hslash$ and $9\hslash$ while the grazing partial wave varies from $l=5\mathrm{}$ to $l=10\mathrm{}$ over the energy range studied. Elastic widths for the low-energy resonances indicate a dinuclear molecular nature; higher-energy resonances appear to originate from a more complex nuclear configuration.

The dissociative recombination of ${\mathrm{H}}_3^{+}$ with electrons can have two exit channels, namely $e$+ ${\mathrm{H}}_3^{+}$→H + H + H (channel I), and $e$+ ${\mathrm{H}}_3^{+}$→${\mathrm{H}}_2$ + H (channel II). A new technique has been developed which has been used to determine the relative contributions of channels I and II to the overall recombination process. Over the energy range from 0.01 to 0.05 eV it has been found that channel I dominates.

The ground state of the ($d^4{s}^2$) configuration shifts by 1.725 eV relative to that of the ($d^{5}s$) on going from Mo to W. This shift, which arises mainly from relativistic contributions to the W energy, is calculated with 2% accuracy by use of the authors' relativistic pseudopotential and the local-spin-density approximation. That the single determinantal broken-symmetry local-spin-density approximation wave function accounts for the spin-orbit energy, which otherwise could be obtained from the spin-orbit mixing of several multideterminantal terms, may be surprising.

A plasma mode driven by the anisotropy of the velocity distribution of charged fusion-reaction products can resonate with the spin precession frequency of one of the plasma components. When these spins are initially polarized, resonant depolarization can occur at a rate considerably faster than the fusion reaction rate, if spatial inhomogeneity effects do not depress excessively the mode amplitude.

The critical opalescence of a binary polymer mixture consisting of polyvinyl methyl ether and deuterated polystyrene was measured by small-angle neutron scattering. In accordance with a mean-field treatment, it was found that the critical exponents $\nu$ and $\gamma$ are 0.5 and 1, respectively; the Ornstein-Zernike scaling function describes the scattering data; and the spinodal is parabolically shaped. However, the dependence of the interaction parameter $\overline{\chi }$ on the composition of the polymer mixture is in conflict with the theoretical result.

The dynamics of the structural changes that take place on a silicon surface following excitation with an intense optical pulse are observed with 90-fs time resolution. The threefold rotational symmetry of the silicon $〈111〉$ surface becomes rotationally isotropic within a picosecond after excitation consistent with a transition from the crystalline to the liquid molten state.

It is shown that the double-honeycomb textures observed in $2H$-Ta${\mathrm{Se}}_2$ have an anomalous elastic compliance due to the change in relative size of different orthorhombic domains. The restoring force against this change is proportional to the domain-wall, or partial discommensuration, energy and tends to zero as the commensurate-incommensurate transition is approached giving a divergent contribution to the elastic compliance—an effect observed by Barmatz, Testardi, and di Salvo some years ago.

Far-infrared magnetoabsorption experiments done in a HgTe-CdTe superlattice are presented. From the results, which are interpreted in terms of interband transitions from valence to conduction subbands, the superlattice band structure has been deduced. These investigations show, in particular, that this superlattice is a quasi zero-energy-gap semiconductor, and yield the first determination of the offset between the HgTe and CdTe valence bands.

SQUID magnetometry measurements on a $\mathrm{Cu}\mathrm{Mn}$ spin-glass reveal that the zero-field-cooled magnetization strongly depends on the time the sample is kept at constant temperature prior to the field application. This result is evidently at variance with the common belief that an equilibrium spin-glass state is quickly obtained after cooling in zero field. The nonequilibrium behavior, as reflected in the complex time dependence of $\frac{\partial m}{\partial \ln t}$, is interpreted to arise from slow dynamics of the relaxation-time spectrum.

Results of photon-stimulated ion-desorption measurements from solid ${\mathrm{N}}_2$, CO, and ${\mathrm{C}}_2$${\mathrm{H}}_2$ are presented in the photon energy range $17<h\nu <35\mathrm{}$ eV. The photon energy dependence of the ion yields illustrates the importance of electron correlation in desorption. On the surface of solid ${\mathrm{N}}_2$, charge localization on the nitrogen atom nearest the surface causes the ${\mathrm{N}}^{+}$ spectral yield to differ from the ${\mathrm{N}}^{+}$ yield from gaseous ${\mathrm{N}}_2$ and to resemble the ${\mathrm{O}}^{+}$ yield from CO. The effect of hole migration on desorption from physisorbed systems is discussed.

A new type of surface polariton, which can occur at the surface of a semiconducting superlattice, is introduced. Because of the quantization of the electron energy levels by the superlattice potential this new polariton mode has the remarkable property of being free from Landau damping.

Optical dephasing of excitonic polaritons in CuCl is directly measured for the first time in the picosecond time domain by means of time-resolved, nondegenerate four-wave mixing. Dephasing of the ${\omega }_1$ polariton pulse is probed by an interrogation ${\omega }_2$ polariton pulse whose group velocity is faster than that of the ${\omega }_1$ polariton pulse. It is found that the dephasing damping constant $\frac{\Gamma }{2}$ of excitonic polaritons is of order of 0.01 meV and increases as $\hslash {\omega }_1$ approaches the exciton resonance energy from below.

Muon spin relaxation measurements have been carried out below the "glass" temperature $T_g$ in $\mathrm{Ag}\mathrm{Mn}$ spin-glasses. The muon spin-lattice relaxation rate varies with field $H$ as $H^{-0.46\mathrm{}\pm 0.05}$ for $0.30<~\frac{T}{T_g}<~0.66$. This suggests that impurity-spin correlations decay with time as $t^{-\nu }$, $\nu \simeq 0.54\pm 0.05$, in contrast to the more usual exponential decay. The present data therefore agree quantitatively with the prediction $\nu \simeq \frac{1}{2}$ of mean-field dynamic theories.

The phenomenon of "dynamical compactification" in a universe with $4+n_c$ dimensions is studied, and it is found that if the whole process is adiabatic, entropy is pumped into the effective four-dimensional universe. Some cosmological consequences of this fact are discussed.

The authors consider nonlinear evolution of the inflationary scale-free spectrum of adiabatic density perturbations in (1) a neutrino-dominated universe (sharp short-wavelength cutoff), and (2) an axion-, gravitino-, or photino-dominated universe (some small-scale power). In (2) galaxy formation begins long before the present (as defined by covariance function), resolving a possible problem in (1). Both models are found to be acceptable upon cluster analysis. The authors believe that a new picture, based on (2), merits consideration.