A method of solving the spin equation in a large circular accelerator with a local spin rotator ("snake") is proposed and compared with a numerical simulation of the spin tracking. We found that (1) the envelope function of the snake structure plays an important role in the spin restoration in passing through the resonance, and (2) a new type of spin depolarization resonance, called snake resonance, appears.

We observe a narrow enhancement in $\phi K^{+}{K}^{-}$ and $\phi {\pi }^{+}{\phi }^{-}$ final states, with a mass of 2.141 ± 0.012 ± 0.010 GeV/${\mathit{c}}^2$ and width of 0.049 ± 0.028 GeV/${\mathit{c}}^2$. The relative branching ratio is $\frac{B(M\to \phi K^{+}{K}^{-})}{B(M\to \phi {\pi }^{+}{\pi }^{-})}=0.49\mathrm{}\pm 0.16$, inconsistent with $M$ being a $q\overline{q}$ state.

Measured helicity nonconservation in ${\pi }^{-}p\to {\rho }^{-}p$ and in $\mathrm{pp}$ elastic scattering indicates that higher-twist contributions are $\frac{1}{10}-\frac{1}{3}$ the size of the leading-twist amplitudes, and that the relative phase between certain $\mathrm{pp}$ amplitudes is at least 16°. The reported levels of helicity nonconservation are therefore consistent with leading-twist perturbative QCD.

The SU(3) ⊗ SU(2) ⊗ U(1) model of strong and electroweak interactions is shown to predict interference at the parton level between gluon and electroweak-boson exchange amplitudes in $q\overline{q}\to \mathrm{Wq}\overline{q}$. This gives rise to parity-nonconserving flavor- and helicity-independent asymmetries of order 0.01 pb at teraelectronvolt energies in the process $p\overline{p}\to W+2\mathrm{}$ jets.

The muon longitudinal polarization $P_L$ in $K_L\to \mu \overline{\mu }$ decay is investigated in the standard model. The induced $\overline{s}\mathrm{dH}$ vertex responsible for $P_L$ turns out to be unexpectedly "large." The measurement of $P_L$ above ∼ ${10}^{-3\mathrm{}}$ will, therefore, be a signal of the existence of a rather light Higgs boson ($M_H\lesssim 10$ GeV). It is also shown that the mechanism of guage-dependence cancellation between Higgs-boson-exchange and box diagrams works even in the standard model.

Two-body decays of charm mesons are analyzed in the quark-diagram formulation, including effects of SU(3) breaking and final-state interactions. Interesting future experiments are also pointed out.

We completely eliminate degrees of freedom in two-dimensional QCD in favor of a single bosonic field. We study the symmetries of the resulting model and its limits of strong and weak coupling.

It is shown that a fully self-consistent equation of state with realistic interactions gives entropy in excellent agreement with recent experimental data. We suggest that entropy production can be reasonably approximated by a free Fermi gas with effective mass.

Fluorine $K$ Auger spectra were measured for a series of alkali-metal and alkaline-earth fluorides excited by Al $K\alpha$ x rays. A new line was observed in some Auger spectra, and the highest intensity of this line was found for KF. The energy and intensity variations of this line depending on the metal ion are explained by a resonant electron-transfer relaxation mechanism following the Auger transition.

A new technique has been developed for determination of the projection of a photofragment's angular momentum vector, J, onto its recoil velocity vector, v. Doppler-profile spectroscopy is used in conjunction with laser-induced fluorescence probing by polarized light. The technique is illustrated by measurements of the CO Doppler profile following photodissociation of OCS at 222 nm.

Absolute cross sections have been measured for double and triple ionization of ${\mathrm{Xe}}^{6+}$ ions by electron impact. Unambiguous experimental evidence is presented for the significant role of multiple-target-electron collisional processes in the triple ionization of ${\mathrm{Xe}}^{6+}$. The peak cross section for the multiple-target-electron process is comparable to that for the single-electron process of ejection of a $3d$ inner-shell electron, which can lead to net triple ionization via Auger cascade. This result is unexpected for an atom in such a high initial stage of ionization.

We report the observation of the subnatural linewidth of Zeeman coherences in the presence of buffer gases by use of polarization-nearly-degenerate four-wave mixing. The origin of the ultranarrow linewidth is attributed to the nonlinear response of the ground state of the resonant system.

The two-photon ($2E1$) decay $2^1{S}_0\to 1^1{S}_0$ in the heliumlike ion ${\mathrm{Kr}}^{34+}$ has been observed and the lifetime measured. Departures are measured for the first time from the predictions of the nonrelativistic theory, and are sensitive to relativistic effects on the transition-matrix elements. The measured lifetime is $\tau \left(\mathrm{measured}\right)=34.08\mathrm{}\left(0.34\right)\mathrm{}\times {10}^{-12\mathrm{}}\mathrm{s}$ compared to $\tau \left(\mathrm{nonrelativistic}\right)=31.94\mathrm{}\left(0.01\right)\mathrm{}\times {10}^{-12\mathrm{}}\mathrm{s}$.

This paper investigates the possibility of observing gain on a free-bound transition, i.e., by stimulated radiative recombination. The basic equations are derived from the Einstein-Milne relations for the continuum. Gain formulas for various plasma conditions are given. A continuously tunable short-wavelength laser seems to be possible.

We argue that the computational requirements for presently envisaged cellular-automaton simulations of continuum fluid dynamics are much more severe than for solution of the continuum equations.

We report recent developments in the modeling of fluid dynamics, and give experimental results (including dynamical exponents) obtained with cellular automata machines. Because of their locality and uniformity, cellular automata lend themselves to an extremely efficient physical realization; with a suitable architecture, an amount of hardware resources comparable to that of a home computer can achieve (in the simulation of cellular automata) the performance of a conventional supercomputer.

Most three-dimensional fusion-plasma-confinement geometries possess symmetric magnetic fields satisfying $B(\theta ,\zeta )=B(-\theta ,-\zeta )$, where $\theta$ and $\zeta$ are poloidal and toroidal flux coordinate angles, respectively. For such configurations with large aspect ratios, the time-reversal symmetry of the collisionless orbits is sufficient to prove that the local diffusion coefficient, $D\left(E_r\right)$, is independent of the sign of the radial electric field, $E_r$. Consequences of this property for neutral-beam injection and for generic root-jumping models for stellarators are discussed.

The angular distribution of light scattered by an extremely dilute birefringent lyotropic phase shows two well-defined Bragg peaks providing strong evidence of a true lamellar order (lamellae ∼ 40 Å thick and 6500 Å apart in the diluent). The steric origin of the stabilization of this stacking is discussed.

Precision measurements of the velocity of third sound in very dilute ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixture films are used to test the formulation of the mixture problem due to Lekner and to test recent predictions for the thickness dependence of the binding energy of the ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ to the film. The results confirm the basic correctness of the calculations of Sherrill and Edwards. Comparison is made to the layered hydrodynamic model.

We report the first accurate study of the temperature dependence of single-molecule spinning and tumbling correlation times in the nematic phase. Whereas the tumbling diffusion is seen to be an ordinary, Arrhenius-type process, the spinning correlation time actually slows down as temperature increases towards the nematic-isotropic transition point. We discuss our results in terms of the peculiarities of diffusion in anisotropic systems; in particular, we emphasize the possible static or dynamic effects of molecular biaxiality.