The production of supersymmetric particles in ultrahigh-energy cosmic-ray interactions in the atmosphere is investigated. We find that the pair production and subsequent decay of a light (∼3–5 GeV) gluino can lead to fluxes of neutral, weakly interacting superparticles which can be comparable to neutrino fluxes. Relevant processes for detecting photinos or scalar neutrinos in large neutrino detectors are discussed and several reactions with cross sections as large as those of ordinary ν interactions are examined.

Besides hadrons and eight electroweak gauge bosons, topological particle theory predicts four generations isodoublet Dirac leptons (e,μ,τ,λ plus neutrinos) and eight generation-changing neutral scalar bosons $H_{\lambda \tau }$, $H_{\lambda \mu }$, $H_{\tau e}$, $H_{\mu e}$, and conjugates. Seven vector bosons, all H’s and λ acquire masses≫1 GeV from direct couplings to heavy elementary hadrons with masses ≳1 TeV. We estimate that $m_{\lambda }$≲1 TeV. H-mediated radiative corrections give masses to μ and τ in first order, to e in second order. Lepton-generation numbers are absolutely conserved and neutrinos acquire small masses but do not mix.

We perform exact numerical calculations of interactions between pairs and chains of skyrmions, and make estimates of many-body forces. The picture of skyrmion interactions that emerges is very different from the one based on the product Ansatz for the chiral field employed in previous studies.

Electric ground-state properties of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ have been measured in a consistent way by observation of the Coulomb interaction of aligned ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ ions with heavy target nuclei. Besides the quadrupole moment ($Q_s$=-3.70±0.08 $e^2$ ${\mathrm{fm}}^2$) and the B(E2,${\mathrm{}(3/2)\mathrm{}}^{\mathrm{-}}$→${\mathrm{}(1/2)\mathrm{}}^{\mathrm{-}}$) value (8.3±0.5 $e^2$ ${\mathrm{fm}}^4$), the tensor moments of the nuclear polarizability ${\tau }_{12}$ and ${\tau }_{11}$ were determined (${\tau }_{12}$=${\tau }_{11}$=0.23±0.06 ${\mathrm{fm}}^3$). Present theoretical investigations on the structure of ${}_{}{}^7{}_{}{}^{}\mathrm{Li}$ reveal difficulties in providing a unified description of all four properties.

We report the first experimental measurements for the energy level of a metastable state of ${\mathrm{Be}}^{\mathrm{-}}$. The ions were produced in sequential charge-exchange collisions between 50- to 60-keV ${\mathrm{Be}}^{+}$ ions and lithium vapor. The center-of-mass energy of autodetaching electrons was found to be 2.53±0.09 eV. This result is in good agreement with previously calculated values for the ${\mathrm{Be}}^{\mathrm{-}}$(1${\mathrm{s}}^2$2s2${\mathrm{p}}^2$${)\mathrm{}}^4$P state energy.

The first measurements of total cross sections for positrons (5–49 eV) colliding with a non-room-temperature gas (namely potassium) are reported. Comparisons of these measurements with the corresponding electron measurements using the same apparatus and technique (a beam-transmission method) indicate an overall degree of similarity that has not been observed for any other target atoms or molecules, which could be related to the large polarizability of potassium atoms.

We present measurements of the dynamic behavior of macroscopic structures observed in a periodically excited air jet. The transitional weakly turbulent state is shown to be characterized by a strange attractor with low dimensionality (ν=2.6), whereas motion of the turbulent flow is not restricted to a low-dimensional attractor.

Rayleigh-Bénard convection is studied in alcohol-water mixtures in which the diffusion of concentration opposes convection via the Soret effect. Near onset, the convective rolls are found to move continuously as traveling waves, in contrast to the stationary roll patterns observed in homogeneous fluids. Dependent upon the temperature difference across the fluid layer (i.e., Rayleigh number), these traveling-wave states are either periodic or chaotic. At larger Rayleigh numbers, time-independent flow is observed which is the same as that expected for the homogeneous fluid mixture.

Heat-transport measurements in a normal-fluid ${}_{}{}^3{}_{}{}^{}\mathrm{-}_{}^4{}_{}{}^{}$He mixture contained in a porous medium and heated from below show a bifurcation to steady or oscillatory flow, depending on the mean temperature. With increasing Rayleigh number R the oscillatory state is entered via a forward Hopf bifurcation with frequency ${\mathrm{\omega }}_{\mathrm{c}}$>0. As the stationary bifurcation is approached by change of the mean temperature, ${\mathrm{\omega }}_{\mathrm{c}}$ vanishes. With increasing R, the oscillatory state terminates with vanishing frequency and finite amplitude in a hysteretic bifurcation to a steady state. Those observations agree with recent theoretical predictions.

Effects of the recently proposed electrostatic ballooning formulation on high-n ballooning instability in a tokamak are investigated. It is found that coupling to drift waves (through finite ion Larmor radius) further destabilizes ballooning instability. The critical poloidal beta is reduced by a factor of 2.

An expression for local power absorption for linear wave propagation in a nonuniform hot magnetoplasma is derived from fundamental principles. The power-absorption definition is used to obtain a local power-conservation relation for a one-dimensional configuration. The formalism is applied to wave propagation in the ion cyclotron range of frequencies where strong damping and mode-conversion processes are present.

A new ordered state characterized by sharp electron diffraction spots showing an arrangement with a twelvefold symmetry axis inconsistent with the existence of a Bravais lattice has been found in small particles of Ni-Cr. Electron microscopic high-resolution structure images of these particles reveal that this ordering state has no translational symmetry but has far-reaching orientational order.

We present for the first time experimental evidence for solute Ni segregation to the surface in Ni-Cu alloys where it has been generally believed that Cu atoms always segregate to the surface in agreement with various theories. A new insight is needed in surface segregation in order to account for our observation of Ni segregation in ${\mathrm{Ni}}_{1\mathrm{-}\mathrm{x}}$${\mathrm{Cu}}_{\mathrm{x}}$ alloys where x is in a range 0.84 to 1.0.

We show that in contrast to the secondary-electron intensity distribution, the spin polarization, P(E), yields useful information about the electron-electron interaction. The ratio of lifetimes of majority- to minority-spin electrons can be determined directly from the measured values of P(E) by ${\mathrm{\tau }}_{\mathrm{\uparrow }}$(E) / ${\mathrm{\tau }}_{\mathrm{\downarrow }}$(E) = 1-${\mathrm{p}}_{\mathrm{B}}$ / 1+${\mathrm{p}}_{\mathrm{b}}$ 1+P(E) / 1-P(E), where ${\mathrm{p}}_{\mathrm{B}}$ is the bulk magnetization.

We measure the low-temperature longitudinal and Hall conductivities in a series of Ge:Sb samples at the approach to the metal-insulator transition. Both conductivities critically vanish with the same exponent of 1, in contradiction to the ratio of 2 predicted by the scaling theory of localization.

Laser resonance-ionization spectroscopy of nitric oxide (NO) molecules desorbed by electron impact from a polycrystalline nickel surface is discussed. This is the first time that ground-state rotational and vibrational populations have been probed for neutrals in electron-stimulated desorption. The results support previous studies that indicate that shallow valence-level excitations dominate the neutral desorption mechanism.

A fractal model is proposed for a rough interface between two materials of very different conductivities, e.g., an electrode and an electrolyte. The equivalent circuit of the model, which takes into consideration the resistance in the two substances and the capacitance of the interface, has the property of the so-called constant-phase-angle element, i.e., a passive circuit element whose complex impedance has a power-law singularity at low frequencies. The exponent of the frequency dependence is related to the fractal dimension. The model also provides insight into the conducting properties of the percolating cluster and the source of the 1/f noise in electronic components.

Arsenic interaction with the Ge(111) surface results in the replacement of the outer Ge layer with an As layer. This system has a 1×1 symmetry and the calculated positions of the As atoms are very close to the positions expected from bulk bond lengths. Ge(111):As is thus a model ideal surface and a comparison is made of an experimental and a theoretical determination of its fully occupied surface band.

We use a spin-coherent representation to derive the spectrum of nonlinear excitations in a spin-S quantum ferromagnetic Heisenberg chain in the continuum limit. Quantum effects split the semiclassical spectrum into two branches—a lower branch of spin-wave-like, large-width solitary waves with negligible quantum corrections for all S, and an upper branch of particlelike, small-width solitary waves subject to significant quantum corrections for low S. The stability of these excitations is briefly discussed.

We study a class of simple, translationally invariant, two-dimensional, nearest-neighbor, isotropic XY models which possess, in addition to the familiar integer vortices, half-integer vortex and ‘‘string’’ excitations. The half-integer vortices interact through both the logarithmic Coulomb potential and a linear potential mediated by the strings. The phase diagram of these models consists of three phases separated by lines of conventional Kosterlitz-Thouless transitions and lines of Ising transitions driven by the vanishing of the tension in the strings.