We have measured a proton NMR dipolar splitting, $\Delta H$, proportional to the "nematic order parameter," in the nematic and smectic-$A$ phases of $p$-cyanobenzylidene-$p$-nonylaniline, at pressures up to 3.5 kbar. The discontinuity in $\Delta H$ at the nematic-smectic-$A$ phase transition decreases from a relatively large value at 1 atm to an unobservably small value at higher pressures. We tentatively identify a tricritical point for this transition at $t_t=140\mathrm{}\pm 4°$C and $P_t=2.89\mathrm{}\pm 0.23$ kbar.

Measurements of the Rayleigh scattering by concentration fluctuations in the coexisting superfluid in ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixtures near the tricritical temperature $T_t$ show a single Lorentzian line of width such that $\frac{\Gamma }{q^2}=D_{\mathrm{eff}}=1.5\mathrm{}\times {10}^{-4\mathrm{}}{\epsilon }^{0.95\pm 0.07}$ ${\mathrm{cm}}^2$ ${\sec }^{-1\mathrm{}}$ for $9\times {10}^{-4\mathrm{}}<~1-\frac{T}{T_t}\equiv \epsilon <~7\times {10}^{-3\mathrm{}}$. Thus the effective diffusion coefficient $D_{\mathrm{eff}}$ is proportional to ${\epsilon }^{+1\mathrm{}}$ and, since the concentration susceptibility ${\left(\frac{\partial x}{\partial \Delta }\right)}_{\mathrm{PT}}$ is proportional to ${\epsilon }^{-1\mathrm{}}$, the effective kinetic coefficient $L_{D,\mathrm{eff}}=\frac{D_{\mathrm{eff}}}{{\left(\frac{\partial \Delta }{\partial x}\right)}_{\mathrm{PT}}}$ is proportional to ${\epsilon }^{+1\mathrm{}}{\epsilon }^{-1\mathrm{}}\sim {\epsilon }^0$.

I have determined with exact ground-state wave function and ground-state energy for a one-dimensional plasma, with density-dependent short-range force. In particular, I am able to approach the thermodynamic limit of finite density, and verify that the ground-state energy is extensive, provided that there is a uniform density of neutralizing charge.

Proton heating varying from 10 to 40% as plasma density is decreased has been observed as a result of energetic $H^0$ beam injection parallel to the discharge current on the ORMAK device. The change in ion temperature agrees with a theoretical heating calculation in both density scaling and magnitude. In contrast to the results reported for the ATC device at Princeton Plasma Physics Laboratory, no measurable heating was observed for an antiparallel beam.

The field-dependent absorption of N in GaP is determined by a new method employing depletion-region modulation. To explain the line shape and the peak increase with $\mathcal{E}$, we propose a Franz-Keldysh-type mechanism. It is based on the field's permitting nondirect transitions, with an orientation dependence determined by the impurity symmetry. We deduce that N has the GaP $X_1$ symmetry, with masses $m_l=(1.35\mathrm{}\pm 0.1)m_0$ and $m_t=(0.175\mathrm{}\pm 0.01)m_0$.

Surface photocurrents have been calculated using the same surface potential-barrier model to evaluate the initial and final photoelectron wave functions and the spatial behavior of the exciting electromagnetic field. The calculations show, for the jellium models employed, that total surface photoyield versus frequency is highly sensitive to surface electronic structure, while surface photocurrent energy and angle distributions are quite insensitive to it.

A simple model of a stack of planar molecular ions is considered in tight-binding approximation. I show that the modulation of the transfer integral of the extended $\pi$-electron wave functions of two adjacent molecular ions by a rotational degree of freedom and the softening of the corresponding zone boundary libron $q_L=\pm \frac{\pi }{z_0}$ leads to an orientational Peierls transition. The possible relevance to the metal-insulator transition in tetrathiafulvalene tetracyanoquinodimethane is stressed.

We observed the magnetic hyperfine interaction of ${}_{}{}^{129}{}_{}{}^{}\mathrm{I}$ in nickel, by allowed $\beta -\gamma$ time-differential perturbed angular correlation, as a consequence of a quadrupole interaction existing in a ferromagnetic cubic lattice.

The propagation of longitudinal sound waves at frequencies between 10 and 520 MHz is analyzed at the ferromagnetic transition of metallic MnP. In spite of the existence of highly asymmetric attenuation about $T_c$, it is shown that the data are consistent with a symmetric critical relaxation time, $\tau$. It is also shown that the reduced attenuation can be scaled by functions of $\omega \tau$ which differ above and below $T_c$.

We obtain the elementary results of a field theory of forces in nuclei due to a scalar meson, treated classically, by means of a simple Hartree treatment. This simple method makes possible estimates of the ratio of the binding energy per nucleon from three-body forces to that from two-body forces. In particular we estimate a new type of three-body force that occurs in the $\sigma$ model.

Systematic investigations of the shape-transitional nuclei ${}_{}{}^{186}{}_{}{}^{}\mathrm{Pt}$ to ${}_{}{}^{194}{}_{}{}^{}\mathrm{Pt}$ by ($\alpha , \mathrm{xn}\gamma$) reactions have revealed a rich variety of high-spin structural phenomena, which can be qualitatively understood in terms of rotation-alignment coupling and the interplay between collective and single-particle excitation modes. Acute backbending in the positive-parity yrast sequences of ${}_{}{}^{188,190,192,194}{}_{}{}^{}\mathrm{Pt}$ is attributed to the intersection of rotation-aligned ($\nu {i_{\frac{13}{2}}}^{-2\mathrm{}}$) and ($\pi {h_{\frac{11}{2}}}^{-2\mathrm{}}$) bands with the ground bands.

A static, spherically symmetric solution of Yang's vacuum gravitational field equations is given which predicts incorrect values for experimental observations. It is argued that Yang's field equations must be supplemented by further restrictions on the class of allowable space-times.

We report new measurements of the inclusive electroproduction of forward protons carried out at the Wilson Synchrotron Laboratory at Cornell University. Data were taken with deuterium at the ($W, Q^2$) points (2.15 GeV, 1.2 Ge${\mathrm{V}}^2$), (2.15, 4.0), and (3.11, 1.2); data were taken with hydrogen at these points and at the points (2.15, 2.0), (2.67, 3.3), and (3.11, 1.7). The invariant structure function is presented in terms of $W$, $Q^2$, and $\omega$.

A search for the production of charmed particles in 15-BeV/c ${\pi }^{+}p$ interactions has been carried out. The search was sensitive to charmed particles in the 1.5 to 4.0 BeV mass range, with lifetimes ≲${10}^{-11\mathrm{}}$ sec, decaying into a strange particle with up to eight additional pions. No evidence for the production of such particles was found.

We have measured the cross section for $p+p\to p+X$ for ${M_X}^2$ up to a constant fraction of $s$. We observe no rise for $130<E<\mathrm{}400\mathrm{}$ GeV. The inelastic cross section for $0<\mathrm{}{M}^2<0.06s$ is 2.50±0.05 mb for various values of $s$ from 263 to 752 Ge${\mathrm{V}}^2$.

We report on the production by neutrinos of an event with negative strangeness. In an exposure of the Brookhaven National Laboratory 7-ft cryogenic bubble chamber to a broad-band neutrino beam 335 events were observed, one of which fits the reaction $\nu p\to {\mu }^{-}{\Lambda }^0{\pi }^{+}{\pi }^{+}{\pi }^{+}{\pi }^{-}$. Alternative explanations are examined and none found with a probability greater than 3 × ${10}^{-5\mathrm{}}$. The event thus represents a large violation of the $\Delta S=\Delta Q$ rule or alternatively the production and decay of a charmed baryon state. The most plausible mass for this state is found to be 2426 ± 12 MeV.

The narrow width of $\psi \mathrm{}\left(3105\right)\mathrm{}$, as an uncharmed member of the $1^{--}$ meson multiplet of SU(4), is discussed in a purely algebraic manner without referring to quarks. A crucial test of this assignment of $\psi \mathrm{}\left(3105\right)\mathrm{}$ is proposed.

It is shown within the context of simple paramagnon theory that if spin fluctuations are responsible for the pairing in superfluid ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, then the direction of paired spins in the $A_1$ phase should be opposite to that of the field-induced magnetization in the normal state, in contradiction to predictions made using weak-coupling theory. Measurements of the direction of paired spins in the $A_1$ phase can thus help to test the paramagnon-pairing hypothesis.

Approximate recursion relations which give upper and lower bounds on the free energy are described. "Optimal" calculations of the free energy can then be obtained by treating parameters within the renormalization equations variationally. As an example, simple lower-bound relations are defined for the two- and three-dimensional Ising models. At the fixed point, a parameter is set variationally, and then critical indices are calculated.

The linear and nonlinear evolution of an instability of one-dimensional filaments in plasma is investigated. The relevance of these results to two-dimensional breakup of the critical surface in laser-plasma interactions is pointed out.