Measurements of the $e^{+}{e}^{-}$ cross section above $B\overline{B}$ threshold are reported. Structures are observed which could be the $\Upsilon \mathrm{}\left(5S\right)\mathrm{}$ and $\Upsilon \mathrm{}\left(6S\right)\mathrm{}$ resonances. The masses and widths are given and compared with various potential-model predictions. Average charged multiplicities and inclusive lepton yields are also presented.

We give some applications for a $\mathrm{CP}$-nonconserving quantity which is invariant under nontrivial rephasings of the Kobayashi-Maskawa mixing matrix. It is shown to resolve one of the two ambiguities involved in defining the concept of maximal $\mathrm{CP}$ nonconservation. The second, more intrinsic, ambiguity is partially resolved in the framework of an especially symmetrical class of parametrizations.

We investigate the possibility of scales of deconfinement in $\mathrm{SU}\mathrm{}\left(N\right)\mathrm{}$ lattice gauge theories with infinitely heavy sources in different representations. We employ Monte Carlo methods for $N=4\mathrm{}$, factorization for $N=\infty$ and strong-coupling mean-field techniques for even $N<~16$. No scales of deconfinement are found.

In models with an additional large scale the low-energy effective Lagrangian may contain terms beyond the standard model which generate kinetic mixing between the $\gamma$ and $Z$. This modifies the coupling of the $Z$ and changes the relation between the masses of the $W$ and $Z$ and the parameters ${\alpha }_{\mathrm{EM}}$, $G_{\mathrm{F}}$, and ${sin\theta }_w^2$. Such an effect, which probes the existence of a higher scale (compositeness, extended hypercolor, etc.) may be seen in future precision measurements of the $W$ and $Z$ masses and $Z$ couplings.

This paper presents evidence of the anomalous interaction mean free path of the relativistic alpha particles emitted from the interaction of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ with emulsion nuclei at 4.5 GeV/c per nucleon. The tracks were followed systematically through the stack. The detailed measurements show clearly that the interaction mean free path is anomalously shorter for fewer centimeters after their emission. The results have been compared with other results obtained from both accelerator and cosmic-ray data.

Cross sections and $\gamma$-ray multiplicities have been measured for neutron evaporation channels in the reactions ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{144}{}_{}{}^{}\mathrm{Nd}$, ${}_{}{}^{37}{}_{}{}^{}\mathrm{Cl}$ + ${}_{}{}^{123}{}_{}{}^{}\mathrm{Sb}$, ${}_{}{}^{64}{}_{}{}^{}\mathrm{Ni}$ + ${}_{}{}^{96}{}_{}{}^{}\mathrm{Zr}$, and ${}_{}{}^{80}{}_{}{}^{}\mathrm{Se}$ + ${}_{}{}^{80}{}_{}{}^{}\mathrm{Se}$ leading to the compound system ${}_{}{}^{160}{}_{}{}^{}\mathrm{Er}$ at common excitation energies. In the near-barrier energy regime average angular momentum transfers depend dramatically on the asymmetry of the entrance channel. The results are interpreted in terms of the ground-state zero-point vibrations.

Correlations between two protons at small relative momenta are presented for ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$-induced reactions on ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ and ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ at 400 MeV. These data are well described by a statistical calculation which incorporates the thermal emission of the particle-unstable nucleus, ${}_{}{}^2{}_{}{}^{}\mathrm{He}$, from the compound nucleus. The good agreement suggests that the emission of particle-unstable light nuclei can be an important decay channel for highly excited nuclear systems, and can strongly influence two-particle correlations.

A search for superheavy elements was made in bombardments of ${}_{}{}^{248}{}_{}{}^{}\mathrm{Cm}$ with ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$ ions performed at projectile energies close to the interaction barrier in order to keep the excitation energy of the compound nucleus $Z=116\mathrm{}$, $A=296\mathrm{}$ as low as possible. No evidence for superheavy nuclei was obtained in a half-life region from 1 μs to 10 yr with a production cross section greater than ${10}^{-34\mathrm{}}$ to ${10}^{-35\mathrm{}}$ ${\mathrm{cm}}^2$.

The $5d7s{}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$ state of barium was resonantly prepared and photoionized. Branching ratios and photoelectron angular distributions were measured for the $6s$ and $5d$ core states of ${\mathrm{Ba}.\mathrm{}}^{+}$ Strong configuration mixing is indicated for the $5d7s{}_{}{}^1{}_{}{}^{}D_2^{}{}_{}{}^{}$ state. The $6s$ core is produced in 43% of the ionization events, and the $5d$-core photoelectron angular distributions show fourth and sixth spherical harmonics in violation of independent-particle predictions.

At energies greater than 200 eV the electron-impact single-ionization cross sections for ${\mathrm{Sb}}^{2+}$($4d^{10}5s^{2}5p$) and ${\mathrm{Bi}}^{2+}$($5d^{10}6s^{2}6p$) ions, ${\sigma }_{2,3}$, are larger than the corresponding cross sections, ${\sigma }_{1,2}$, for ${\mathrm{Sb}}^{1+}$ and ${\mathrm{Bi}}^{1+}$ ions, respectively. This extraordinary behavior is a consequence of the fact that the $4d\left(5d\right)\mathrm{}$ hole configurations goes from autoionization to bound when the charge state of the Sb (Bi) ions is increased from +1 to +2. Additionally, multiple ionization measurements (${\sigma }_{1,3}$ for Sb and ${\sigma }_{1,3}$, ${\sigma }_{2,4}$, and ${\sigma }_{3,5}$ for Bi) are presented for electron energies up to about 1000 eV.

We present experimental evidence for a modulation in the time-resolved atomic fluorescence light following the photodissociation of ${\mathrm{Ca}}_2$ molecules by a pulsed laser. This modulation is due to an interference effect involving two atoms recoiling in opposite directions, while only one photon is emitted. The period of the modulation is equal to the time for the interatomic distance to increase by an optical wavelength.

Photoelectron angular distributions have been measured for nonresonant two-photon ionization of cesium and rubidium atoms just above the ionization threshold. The photoelectron energies ranged from 25 to 100 meV. The results are compared with theoretical estimates based on nonrelativistic atomic wave functions. Initial results are also presented for above-threshold ionization in cesium.

Many-body perturbation and coupled-cluster methods using numerical Hartree-Fock and correlating orbitals are applied to diatomic molecules for the first time. For LiH, the correlation energy is within 0.001 a.u. of the nonrelativistic correlation energy limit, which provides an energy of -8.069 a.u. compared to the exact result of -8.070. These results suggest that highly accurate results for diatomic molecules may be obtained by the proposed approach.

We present an analytical model for large-scale turbulence, based on a new closure which depends on the growth rate of the instability-generating turbulence. For convection in stars we recover the results of the mixing-length theory and for laboratory convection we recover the $N\sim R^{\frac{1}{3}}$ law. The present model can readily be extended to include magnetic fields and rotation.

It is shown that during ion-Bernstein-wave heating experiments, nonlinear ion Landau damping absorbs efficiently the incident Bernstein waves in present-day tokamak and tandem-mirror plasmas. Further, this nonlinear absorption will dominate absorption by minority (impurity) ions.

The self-diffusion tensor was studied as a function of the diffusion time in the isotropic and the cholesteric phases. In the cholesteric phase the elements of the self-diffusion tensor are not constant but strongly decrease with increasing diffusion time. No such effect was observed in the isotropic phase. The above method seems to represent a useful technique to study the low-frequency part of the spectrum of the velocity autocorrelation function.

Coherent inelastic neutron scattering provides detailed information about the correlated atomic displacements in the vibrational modes of a glass. As an example, we show the wave-vector dependence of the scattering function of vitreous Si${\mathrm{O}}_2$ corresponding to different peaks in the one-phonon density of states. Pending the availability of results from computer simulations, we give a qualitative comparison with the Sen-Thorpe model.

It is demonstrated that for short-range forces the density profile of the planar interface between fluid phases in three dimensions does not exist in the absence of a macroscopic external field such as gravity. This result holds for all nonzero values of the temperature and implies the absence of a roughening transition in continuous fluid interfaces in three dimensions, in contrast to the existence of such a transition in interfaces of three-dimensional lattice gases.

The surface excess amount $\Gamma$ of S${\mathrm{F}}_6$ on graphitized carbon (measured by a new volumetric technique) rises sharply on approach to the critical point along an isochoric path from the one-phase region of the fluid. For a limited range of reduced temperatures ($0.02>t>\mathrm{}0.001\mathrm{}$) $\Gamma$ varies as a power law in $t$. Our data yield an exponent $x=0.5\mathrm{}$, whereas the Fisher-de Gennes scaling theory predicts $x=\nu -\beta =0.3\mathrm{}$. Close to criticality confined-geometry effects become important.

We show that deduction of the pair interaction from structural data for simple liquids is feasible even under the triple-point condition. We use an iterative predictor-corrector method based on the modified hypernetted-chain equation and on simulation. We show that simulation can give enough accuracy to test inversion schemes.