Using the Colubia University—Stony Brook detector we have measured the production of energetic electrons ($E>\mathrm{}1\mathrm{}$ GeV) in $e^{+}{e}^{-}$ annihilations in the center-of-mass energy range 10.4 to 11.4 GeV. We observe an enhanced electron signal at the ${\Upsilon }^{\prime \prime \prime }\mathrm{}\left(4S\right)\mathrm{}$ resonance, which we interpret as evidence for the $\beta$ decay of a new flavor of quark, $b$, bound within a new flavor meson, $B$. We derive a branching ratio for $B\to \mathrm{Xe}\nu$ of (13.6 ± 2.5 ± 3)%. The observed energy spectrum of the electrons favors the decay $b\to \mathrm{ce}\nu$ over $b\to \mathrm{ue}\nu$.

The elastic differential cross section of 5.75-GeV/c deuterons scattered from deuterium has been measured over a range of $0.125<-t<\mathrm{}2.0\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. The result shows a narrow interference minimum at $-t=0.18\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$, but does not have a simple exponential behavior in the double-scattering region. The latter effect is attributed to constructive interference between the two double-scattering amplitudes, which have different $t$ dependences. The results are compared to existing data and to a Glauber-model calculation.

The population of yrast states in ${}_{}{}^{152}{}_{}{}^{}\mathrm{Dy}$ and properties of continuum $\gamma$ rays have been measured as a function of input angular momentum, $l$, via the ${}_{}{}^{122}{}_{}{}^{}\mathrm{Sn}$(${}_{}{}^{34}{}_{}{}^{}\mathrm{S}$,$4n$) reaction. With increasing $l$ an eventual saturation of the high-spin population with a narrow region of yrast feeding is observed, together with an enhanced yield in the continuum spectra. This implies that the decay of very-high-spin states is diverted from the yrast line by continuum cascades and suggests collective modes which might be built on high-$J$ particle states.

We have measured the differential cross section $\frac{d^2\sigma }{d\Omega }$ $\mathrm{dT}$ and estimated the total cross section ${\sigma }_T$ for the double charge exchange reaction ${}_{}{}^4{}_{}{}^{}\mathrm{He}({\pi }^{+},{\pi }^{-})4p$ at 140, 200, and 295 MeV. The values for ${\sigma }_T$ are at least an order of magnitude larger than predictions based on sequential single charge exchange $\pi -N$ scatterings. It is possible, therefore, that ${}_{}{}^4{}_{}{}^{}\mathrm{He}$(${\pi }^{+}$,${\pi }^{-}$) is dominated by other processes, such as the formation of a $\Delta$ in the intermediate state or scattering from meson exchange currents.

The velocity distributions of electrons emerging from aluminum with 0.5-1.4-MeV protons at similar velocities (convoy electrons) have two clearly separated components. The widths of the broad components have properties consistent with theories of charge transfer to the continuum. The narrow components behave very differently and might be indicative of solid-state effects.

We describe the measurement of the atomic $g$ factor of the negative sulfur ion in the ${}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}$ ground state. This measurement uses a new technique for observation of microwave transitions in negative ions. Zeeman transitions in ${}_{}{}^{32}{}_{}{}^{}\mathrm{S}_{}^{-}{}_{}{}^{}$ ions confined in a Penning trap are made observable through state-selective photodetachment. The magnetic field is measured by driving the cyclotron motion of electrons trapped in the same trap. The $g_J$ factor is found to be 1.333 984(28).

A laser diagnostic yielding detailed space and time resolution of the ion-velocity distribution function reveals that ions ejected by electrostatic instabilities can form a frequency-coherent beam circulating diamagnetically at large radii around the unstable region. This results in anomalous transport with fluxes and over distance scales much larger than conventional processes.

The helium ash exhaust function of a divertor has been experimentally demonstrated. Helium atoms accumulate in the divertor region as the electron density of the main plasma increases. With a helium concentration of ∼ 1.6% of electron density in the main plasma, neutral helium pressure at the divertor region is as high as 1.0×${10}^{-4\mathrm{}}$ Torr. This experiment indicates the possibility of helium ash exhaust in an $\alpha$-particle-heated diverted tokamak with use of pumping ducts of a practical size.

We have determined the adsorption energy of H↓ on ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixtures to be $\frac{{\epsilon }_a}{k}=0.34\mathrm{}\pm 0.03$ K, essentially independent of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ concentration. We observe a pure second-order decay of the density due to surface recombination with rate constant $\frac{K_s}{T^{\frac{1}{2}}}=1.4\mathrm{}\times {10}^{-9\mathrm{}}$ ${\mathrm{cm}}^2$ ${\mathrm{K}}^{-1/2\mathrm{}}$ ${\mathrm{S}}^{-1\mathrm{}}$ at $B=8\mathrm{}$ T. The nuclear relaxation time $T_1$, predicted to be of order hours, is found to be of order seconds by an indirect measurement. H↓ remained gaseous down to $T=0.085\mathrm{}$ K, the lowest temperature measured.

We have observed an unexpectedly strong effect of the squashing mode in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-$B$ on the longitudinal acoustic impedance $Z$. Most peculiar is the behavior of the reactive part $Z^{\prime \prime }$ which displays both large positive and negative excursions. Our analysis illustrates the role of the boundary conditions on the superfluid order parameter and of the crossover with temperature of the squashing mode from a propagating wave with velocity $c_{\mathrm{sq}}$ (which is measured) to a nonpropagating surface wave (whose imaginary velocity accounts for the anomalies of $Z^{\prime \prime }$).

Variational many-body wave functions for the ground state of liquid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ which include triplet and backflow correlations are investigated with use of Monte Carlo integration. Our energy of - 1.9°K removes half of the discrepancy between previous Jastrow-Slater calculations and experimental results. The first exact results for mass-three bosons are also presented. Triplet correlations in the variational wave function are equally effective in lowering the energy of both mass-three bosons and ${}_{}{}^3{}_{}{}^{}\mathrm{He}$.

The long-wavelength amplitude mode of the charge-density-wave state modulates the average density of states at the Fermi surface leading to a coupling between it and the order parameter for superconductivity. This is shown, in a gauge-invariant theory, to lead to a bound state below twice the BCS gap. Our results are discussed in the context of recent experiments on $2H$-Nb${\mathrm{Se}}_2$.

We report differential cross sections for $h+p\to X+p$ ($h={\pi }^{\pm },K^{\pm },p^{\pm }$) at 100 and 200 GeV/c in the region $0.025<\mathrm{}\left|t\right|<0.095\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ and $\frac{{M_X}^2}{s}<0.1\mathrm{}$.

An electronic band-structure investigation of the charge topology and the eigenvalue spectrum of the ${\mathrm{Si}}_2$ molecule is presented with use of the full-potential linearized augmented plane-wave method for thin films. The inclusion of spin polarization is found to be of fundamental importance in order to obtain the correct description of the ground state (paramagnetic calculations do not converge to any ground state) and to elucidate earlier controversies.

We demonstrate that reduced quantum fluctuations or squeezing are present in both the atomic observables and the radiation field produced by a two-level atom undergoing resonance fluorescence.

An effective Poisson's ratio is introduced for anisotropic materials as the negative ratio of transverse and longitudinal strains averaged over all transverse directions. It is shown that for certain orientations of the applied force this effective Poisson's ratio assumes negative values for $\alpha$-quartz. This implies that such a bar increases its cross section under length extension.

A numerical simulation of the lower-hybrid drift instability is carried out in which an electric drift toward the neutral sheet is present. It is found that lower-hybrid drift waves, which are excited usually in a transient fashion and decay to a low level in a closed system, are reexcited and execute recurrent growth in the presence of particle drift toward the neutral sheet. Consequently, anomalous resistivity also exhibits a recurrent generation.

By limiting attention to the lowest-order Fourier modes we obtain a theory of the Fermi-Pasta-Ulam recurrence that gives excellent agreement with recent numerical results. Both the predicted period of the recurrence and the temporal development of the $n=0\mathrm{}$ mode are very good fits. The maximum of the $n=1\mathrm{}$ mode, however, is off by about 30%. (The nonlinear Schrödinger equation governs the development of the envelope of the electric field of a nonlinear Langmuir wave in the plasma-physics context. It also describes gravity waves in deep water.)

It is shown that plane ion-acoustic solitons are unstable in magnetized plasmas if the magnetic field is greater than a critical value which roughly corresponds to the condition that the soliton width equals the ion gyroradius. On the other hand, ion-acoustic solitons are stable if their amplitudes exceed a corresponding magnetic-field—dependent threshold. Limitations of previous models are discussed.

Discommensurations and dislocations in the incommensurate charge-density-wave structure of $2H$-Ta${\mathrm{Se}}_2$ have been observed directly by dark-field transmission electron microscopy with use of satellite reflections produced because of the phase transition. We have imaged the domain structure in the striped phase on warming above 92 K. Discommensurations are found to have a width ∼ 150 Å and their spacings vary in the expected manner with temperature.