Pyroelectricity has been observed in the smectic-$C$ and smectic-$H$ phases of $l-p$-decyloxybenzylidene-$p^{\prime }$-amino-2-methylbutylcinnamate after the material is poled in a dc field. The observed pyroelectric coefficient is consistent with an estimate of its theoretical value.

A new approximant is proposed for the critical correlation function $g\left(y\right)\mathrm{}$ of $y=k\xi$, where $\xi$ is the correlation length and $k$ the wave number of an order-parameter fluctuation. The approach involves truncating the spectral function associated with the three-term Fisher-Langer approximant in a manner suggested by the requirement of a three-particle threshold. The resulting $g\left(y\right)\mathrm{}$ is accurate to better than 0.03% everywhere for the two-dimensional Ising model. Results for the three-dimensional case are consistent with $\epsilon$-expansion and high-temperature series results.

The total cross section for hadron production by inelastic electron scattering at 3.2° from a number of nuclei has been measured at several virtual photon energies at fixed $Q^2=0.1\mathrm{}$ ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$. The hadronic cross section is measured directly, by detecting at least one hadron in coincidence with the scattered electron. The results show very little shadowing and no detectable energy dependence. These observations contradict vector-meson dominance.

We present here a measurement of six branching ratios of $\psi \mathrm{}\left(3095\right)\mathrm{}$ corresponding to the decays $\psi \mathrm{}\left(3095\right)\mathrm{}\to \rho \pi$, $2\left({\pi }^{+}{\pi }^{-}\right)$, $2\left({\pi }^{+}{\pi }^{-}\right)1\mathrm{}{\pi }^0$, $3\left({\pi }^{+}{\pi }^{-}\right)$, $3\left({\pi }^{+}{\pi }^{-}\right)1\mathrm{}{\pi }^0$, and $4\left({\pi }^{+}{\pi }^{-}\right)1\mathrm{}{\pi }^0$. From this study, the isospin and $G$-parity quantum numbers are found to be $I^G=0^{-}$.

The stability of the vacuum sets a lower bound of order $\alpha {G_{\mathrm{F}}}^{-\frac{1}{2}}$ on the Higgs-boson mass. For the simplest SU(2) ⊗ U(1) model, this lower bound is $1.738\alpha {G_{\mathrm{F}}}^{-\frac{1}{2}}$, or 3.72 GeV.

Data from a 15-GeV/c ${\pi }^{+}d$ experiment have been used to search for both short- and long-lived narrow resonances. No statistically significant high-mass narrow resonance has been observed up to a mass of 5 GeV. There is a single long-lived $V$ that remains unexplained. Cross-section limits (95% confidence level) of 0.7 μb for the long-lived possibility and 2 to 4 μb for the short-lived possibilities have been obtained.

Angular distributions presented for reactions ${}_{}{}^{40,42,44}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{13}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$)${}_{}{}^{39,41,43}{}_{}{}^{}\mathrm{K}$ (transferred $L=1\mathrm{}$, at 68-MeV bombarding energy are observed to oscillate out of phase with exact, finite-range, distorted-wave-Born-approximation (DWBA) calculations. It is shown that differential cross sections for $L=1\mathrm{}$ transfer reactions are particularly sensitive tests of the DWBA. Simple arguments follow which indicate that the difficulty in fitting present data lies with our understanding of the reaction mechanism.

Inelastic scattering of ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ projectiles from ${}_{}{}^{144}{}_{}{}^{}\mathrm{Nd}$ has been studied at an incident energy of 70.4 MeV. The differential cross sections for exciting low-lying collective states of the target and projectile are compared to distorted-wave Born-approximation (DWBA) and coupled-channels calculations. Standard DWBA calculations using known Coulomb matrix elements fail to fit the data. Coupled-channels calculations, however, can account for these data and show a strong sensitivity to target and projectile reorientation matrix elements.

Differential cross sections for ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$(${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$)${}_{}{}^{50}{}_{}{}^{}\mathrm{Ca}$ have been measured at 50 MeV. The ground-state transition has been analyzed with a two-nucleon transfer, distorted-wave Born-approximation code including finite-range and recoil effects. The calculations underpredict the experimental cross sections by a factor of 5, which is similar to the factor of 4 for ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}(t, p)$. However a large discrepancy is found between the corresponding factors for two-neutron pickup from ${}_{}{}^{48}{}_{}{}^{}\mathrm{Ca}$.

We have found striking periodic intensity fluctuations in the anisotropy of noncharacteristic x-ray radiation emitted in Ca-Ca, Fe-Fe, and Ni-Ni collisions. It is shown that the properties of this new effect can be interpreted as quasimolecular transitions in a rotating two-center system.

The effect of magnetic mirroring on convective transport in a thermal plasma with ergodic field lines is investigated by computer simulation. It is found that mirroring significantly enhances convective transport and estimates show that this effect can be important for existing fusion devices.

I investigate the two-ion hybrid resonance for a warm, collisonless plasma and find an approximate dispersion relation appropriate for a toroidal fusion plasma. The fast Alfvén wave propagates on both sides of the resonance, so the tunneling factor is calculated and for fusion plasmas it is found that fast waves incident from the high-magnetic-field side will undergo mode conversion to an ion-Bernstein mode and those incident from the low-field side will be reflected.

The resonant ion-beam—driven electrostatic ion-cyclotron instability is identified. Measured dispersion relation and onset versus beam energy and density agree with numerical calculations based on a theory which includes beam-acoustic terms. After amplitude saturation, velocity-space diffusion of the beam ions is observed.

A scaling analysis of the adiabatic eigenstates of an electron placed in a deformable continuum with and without the presence of a Coulombic defect is set forth. This procedure enables us to obtain exact information about the system's adiabatic eigenstates for various models of the electron-lattice interaction.

We report measurements of the $L_{\mathrm{I}\mathrm{I},\mathrm{I}\mathrm{I}\mathrm{I}}$ x-ray threshold in Mg at momentum transfers of $q=0\mathrm{} \mathrm{and} 1.8$ ${\mathrm{\AA }}^{-1\mathrm{}}$. We found that a straightforward application of the theory of Mahan, Nozières, and De Dominicis failed to describe the data. We conclude that for Mg, and probably for all polyvalent metals, other effects are at least as important as this theory for describing absorption threshold shapes.

We have measured the ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$-${}_{}{}^{19}{}_{}{}^{}\mathrm{F}$ dipolar energy in Ca${\mathrm{F}}_2$, as deduced from the first moment of the ${}_{}{}^{43}{}_{}{}^{}\mathrm{Ca}$ resonance signal, as a function of the fluorine-fluorine energy. The Ca-F energy, which depends on the local longitudinal susceptibility of the fluorine spins, is theoretically expected to peak at the paramagnetic-antiferromagnetic transition. Such a peak is indeed observed.

The soft x-ray emission spectra for fresh films of LiF, LiCl, and LiBr are presented. Prominent structures in these spectra above the ${\mathrm{Li}}^{+}$ $1s$ emission edge are shown to give a direct observation of the radiative decay of $K$-shell cation excitons in these materials.

We have measured the cross section for ${\mu }^{+}{\mu }^{-}$ production in the reactions $({\pi }^{+}, p)+\mathrm{Be}\to {\mu }^{+}+{\mu }^{-}+X$, at an incident momentum of 150 GeV/c. This Letter covers the pairs with masses above 2 GeV/${\mathit{c}}^2$, in which region the signal is dominated by production of the $J\left(3.1\right)\mathrm{}$. No events with $\mu$-pair mass >4.1 GeV/${\mathit{c}}^2$ were seen, although the experiment is sensitive up to ≥12 GeV/${\mathit{c}}^2$.

We have studied the radiative decays of the vector mesons in two SU(3)-breaking schemes. In our models we find it hard to reconcile the newly measured radiative widths of $\rho \to \pi \gamma$,, $K^{0*}\to K^0\gamma$, $\varphi \to \pi \gamma$, and $\varphi \to \eta \gamma$ with the older measurements and upper bounds on other radiative rates. In particular we have difficulty in understanding the narrow radiative width of $\rho$ and the upper bound on $K^{+*}\to K^{+}\gamma$..

The photoneutron polarization from states near threshold was measured, for the first time, for the reaction ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}(\gamma , n_0){}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ throughout the neutron energy range 500 to 1000 keV. Spin and parity assignments were made for these states. The giant $M1\mathrm{}$ resonance in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ was found to be less fragmented than previously thought. The data suggest that there is some "missing" $M1\mathrm{}$ strength in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$.