We consider the supersymmetric Higgs effect, in which a spin-½ Goldstone fermion is transformed away by a redefinition of the supergravity fields and the spin-$\frac{3}{2}$ gauge field acquires the degrees of freedom appropriate to finite mass. More generally we discuss the consistency and physical applicability of supergravity theories with broken local supersymmetry.

A new method of exploring the contents of the renormalization-group equations for discrete spins is introduced. The equations are expanded in low-temperature series and the truncated series are used to obtain the critical exponents and critical temperature of a system. The method is demonstrated on the planar triangular Ising lattice and the critical parameters are found to be within a few percent of the exactly known values in third nonvanishing order of approximation.

We give an explanation of the $\mathrm{CP}$ conservation of strong interactions which includes the effects of pseudoparticles. We find it is a natural result for any theory where at least one flavor of fermion acquires its mass through a Yukawa coupling to a scalar field which has nonvanishing vacuum expectation value.

The characteristics of the surviving nucleon in $\overline{p}d$ annihilation are analyzed in terms of a double-scattering model with only two free parameters. Evidence is presented that the surviving nucleons not only may be very different dynamically from the true-spectator nucleon in the annihilation process, but also may have a different identity through charge exchange in the double-scattering process.

Data are presented on production by 200-GeV/c hadrons incident on beryllium of both single particles and jets (groups of particles) with high $p_T$ (transverse momentum). The experiment was performed in a wide-aperture multiparticle spectrometer at Fermilab. The jet and single-particle cross sections have a similar shape from $p_T=3\mathrm{} \mathrm{to} 5$ GeV/c but the jet cross section is over two orders of magnitude larger. The distributions of charged-particle momenta show striking similarities to those observed in lepton-induced processes.

Results on the proton structure function, $\nu W_2$ are presented for $0.3<\mathrm{}{q}^2<50\mathrm{}$ Ge${\mathrm{V}}^2$ and $5<\mathrm{}\nu <130\mathrm{}$ GeV. They are compared to earlier data and displayed to demonstrate violations of scaling. Values are reported for the energy-momentum sum rule and for $R\equiv \frac{{\sigma }_L}{{\sigma }_T}$ over a limited kinematic region.

Discrete yrast transitions from states with spins up to $30\hslash$ have been observed in ${}_{}{}^{158}{}_{}{}^{}\mathrm{Er}$ from ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ar}$-induced compound-nucleus reactions. A second discontinuity in the level sequence occurs around $I=28\mathrm{}\hslash$. Possible causes and implications of this effect are discussed.

Recent analyses of fission probabilities for ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ in ${}_{}{}^{236}{}_{}{}^{}\mathrm{U}(t, pf)$ and ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}(\gamma , f)$ suggest the possiblity of two distinct second saddle points which provide two independent paths to fission. These two saddle points consist of one which is mass asymmetric and axially symmetric and another which is axially asymmetric and lies ∼300 keV higher. Potential-enery calculations based on single-particle corrections to the liquid-drop surface corroborate the existence of such a complex structure at the second barrier.

The mechanism of the reaction ${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}({}_{}{}^{16}{}_{}{}^{}\mathrm{O}, {}_{}{}^{12}{}_{}{}^{}\mathrm{C}\alpha ){}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ at 65.6-MeV incident energy has been examined with use of coincidence techniques. It is shown that the broad bell-shaped peak observed in ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ singles spectra corresponds to an $\alpha$-transfer-like process leading to fixed excitation energy in the $\alpha$+${}_{}{}^{27}{}_{}{}^{}\mathrm{Al}$ system. The $\alpha$-${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ angular correlation, however, is forward-peaked along the momentum-transfer direction, suggesting that the decay time of the system is less than required for equilibration into ${}_{}{}^{31}{}_{}{}^{}\mathrm{P}$.

A peak in the yield from the electron-induced fission of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ has been observed at an excitation energy of 28.3 MeV, decaying by the channel ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(g.s.) + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}_{}^{2+}{}_{}{}^{}$ (4.43 MeV). The angular distribution of the carbon nuclei from this feature follows ($1-{{cos}^4\theta }_{\mathrm{c}.\mathrm{}\mathrm{ }\mathrm{m}.\mathrm{}}$) indicating an assignment of $J=2\mathrm{}$ with a projection along the fission axis of $K=2\mathrm{}\hslash$. The observed peak could be due to excitations of the giant quadrupole resonance in the prolate well of ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$.

A theory of the off-shell $\pi N$ $t$ matrix is proposed. The theory, which employs dispersion-theoretic techniques, incorporates the on-shell information, including the inelasticities, and derives the additional information required to continue off shell from the underlying field theory. Results are presented for the $P$-wave states and are compared with those of other approaches.

Unexplained intensity oscillations of ∼20-GHz frequency are observed to modulate the radiative decay of the $3{{}_{}{}^2{}_{}{}^{}P_{\frac{1}{2}}^{}{}_{}{}^{}}^{\circ }$ level of ${\mathrm{Cu}}^{18+}$.

We have investigated the grazing-angle scattering of fast ions from solid surfaces. We establish that the circular polarization of light emitted from the scattered ions, and hence the ion orientation, varies strongly with the ion scattering angle. We show that the nearly elastic ion-surface collisions produce maximum allowed orientation of states with very small alignment.

We present measurements of the electron cyclotron emission from high-density ($n_{e0\mathrm{}}>3\mathrm{}\times {10}^{19}$ ${\mathrm{m}}^{-3\mathrm{}}$) low-runaway plasmas produced in the TFR tokamak device. The emission is, as predicted, self-absorbed, but contrary to expections is the same both along a major radius and along a vertical chord, is the same in both the extraordinary and ordinary modes, and peaks at the plasma frequency and, in addition, at $n$ times the electron cyclotron frequency (for $n=1, 2, 3, 4$). We compare the measurements with the predictions of theory.

Measurements are made on spatial evolutions of a large-amplitude wave packet of electron plasma wave in a collisionless plasma. There appears a new wave emitted in front of the wave packet, which results in a spreading of the wave packet along the propagation direction.

The enhancement by a magnetic field of the deposition of energy by a relativistic electron beam is formulated via the diffusion approximation to the relativistic Fokker-Planck equation, valid when mean free path and/or gyration radius are much less than other characteristic lengths. Analytic solutions are given for a beam normally incident on a slab with $\overrightarrow{\mathrm{B}}$ parallel to the face. These indicate that the effect can be important.

A density-functional theory capable of predicting free energies and spatially dependent number densities of simple classical fluids is applied to the case of argon films in the presence of a solid carbon dioxide substrate. For pressures less than the saturated vapor pressure, a new phase transition for which the order parameter is the film thickness is described. The phases are the usual unsaturated film and a one- or two-atomic-layer structure localized at the argon-C${\mathrm{O}}_2$ interface.

We have observed Shubnikov—de Haas oscillations associated with the quantum sub-bands created in superlattices made of periodic layers of GaAs and ${\mathrm{Ga}}_{1-x}{\mathrm{Al}}_x\mathrm{As}$. By controlling the periodic potential profile, a variety of sample with sub-bands of different degrees of two-dimensionality have been prepared for investigation. The observed oscillatory behaviors agree with those predicted from the Fermi surfaces calculated theoretically on the basis of the superlattice configuration and the electron concentration.

Positron-annihilation experiments in helium gas have shown anomalies in annihilation rate near the gas-liquid critical point which indicate the formation of positron self-trapped states in helium droplets. We present theory which appears to confirm the existence of self-trapped states and accounts quantitatively for the positron-annihilation rate in the range of densities and temperatures over which these states are stable. The droplets have a maximum density 2.4×${10}^{22}$ ${\mathrm{cm}}^{-3\mathrm{}}$ and are typically 15 to 25 Å in radius.

Measurements of luminescence spectra in pure Si demonstrate the dissociation of excitons with increasing excitation intensity. The density at which the dissociation begins and its temperature variation agree well with Mott's predictions. We have also determined a phase diagram of Si, including the effects of electron-hole-liquid and Mott transition.