Measurements are reported for the process $e+p\to e+p+x^0$ at $Q^2=0.3,0.6, \mathrm{and} 1.2$ Ge${\mathrm{V}}^2$ and for $0.875<~m_x^{}{}_{}{}^2<~1.875$ Ge${\mathrm{V}}^2$. Protons are produced predominantly backward in the center-of-mass frame, with average transverse momenta increasing with $Q^2$.

The charge asymmetry in the decay $K_L^{}{}_{}{}^0\to {\pi }^{\pm }{\mu }^{\mp }\nu$ has been measured to be (2.78 ± 0.51) × ${10}^{-3\mathrm{}}$, leading to a value of $\mathrm{Re}\epsilon$ in good agreement with the results from the $K_L^{}{}_{}{}^0\to 2\pi$ decay modes.

Differential cross sections for ${\pi }^{\pm }p$, $K^{\pm }p$, $\mathrm{pp}$, and $\overline{p}p$ elastic scattering were measured at 3, 3.65, 5, and 6 $\frac{\mathrm{GeV}}{c}$ for momentum transfers from 0.03 to 1.5 Ge${\mathrm{V}}^2$ using the Argonne effective mass spectrometer. Particular attention was paid to the relative particle-antiparticle normalization. The crossover points are consistent with no energy dependence, average values being 0.14 ± 0.03, 1.190 ± 0.005, and 0.160 ± 0.007 Ge${\mathrm{V}}^2$ for $\pi$'s, $K$'s, and protons, respectively.

We investigate the possibility that the physically relevant currents may be different from those that satisfy the usual $\mathrm{SU}\mathrm{}\left(3\right)\mathrm{}\otimes \mathrm{SU}\mathrm{}\left(3\right)\mathrm{}$ algebra. This approach offers new insight into the nature of the Cabibbo angle. A modified soft-pion theorem for the $K_{l3\mathrm{}}$ decay is also obtained, which provides better agreement with the present data.

We define free, covariant Euclidean Bose and Fermi fields and establish their relation with the corresponding relativistic free fields. Using this correspondence we prove a Feynman-Kac formula for boson-fermion models.

We have measured the asymmetry parameter $\Sigma =\frac{({\sigma }_{\parallel }-{\sigma }_{\perp })}{({\sigma }_{\parallel }+{\sigma }_{\perp })}$ for the photoproduction of $\varphi$ mesons with photons polarized parallel and perpendicular to the plane of decay for the reaction $\gamma p\to \varphi p\to K^{+}{K}^{-}p$. We find $\Sigma =0.985\mathrm{}\pm 0.12$ at a photon energy of 8.14 GeV and $\mathrm{}\left|t\right|\mathrm{}$ of 0.2 ${\left(\frac{\mathrm{GeV}}{c}\right)}^2$, consistent with pure diffraction production, or pure naturalparity Regge exchange.

In high-velocity ion-atom single collisions, a strong dependence of target x-ray production cross sections upon the ionic charge state has been observed. Experiments were performed in thin gas targets of argon, krypton, and xenon with 35.7-MeV fluorine ions incident in charge states +5 to +9. Production cross sections for Ar $K$, Kr $L$, and Xe $L$ characteristic lines increase by as much as a factor of 5 with increasing incident charge state but cannot be fitted by a $q^2$ dependence.

We report a calculation of the order $\left(\frac{m_e}{m_p}\right){\alpha }^2\ln {\alpha }^{-1\mathrm{}}$ corrections to the hyperfine splitting (${\nu }_H$) of the hydrogen ground state. The result $\Delta {\nu }_H=\frac{8}{3}{\left(\frac{m_e}{m_p}\right)}^2{(1+\frac{m_e}{m_p})}^{-5\mathrm{}}c{\alpha }^4{R}_{\infty }\ln {\alpha }^{-1\mathrm{}}\mathrm{}[9+7k(1+k)-(\frac{m_e}{m_p}\left)k\right(3+14k\left)\right]=0.0016\mathrm{}$ MHz (1.1 ppm) is used in conjunction with the corresponding formula for the muonium hyperfine interval to obtain an estimate of the proton polarizability.

The Mössbauer recoilless fraction is found to show anomalous temperature dependence for a ${}_{}{}^{161}{}_{}{}^{}\mathrm{Dy}$ source in a molybdenum metal host, decreasing by almost a factor of 5 as the temperature decreases from 300 to 25°K, then increasing again at 4.2°K.

We have measured the angular distribution of phonons radiated from a cleaved (100) face of a sodium fluoride crystal, pulse heated to $T\sim 0.5$ K, into liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ at $T<\mathrm{}0.1\mathrm{}$ K. The distribution shows a sharp peak superimposed on a low-amplitude background extending to ∼35° to the normal. The peak width is consistent with a critical cone ${\theta }_c={4.25}^{\circ }$ calculated under the assumption of conservation of phonon wave vector parallel to the interface.

An extraordinary incident wave, propagating along the major radius through the ST tokamak plasma, is used to generate a second-harmonic wave inside the plasma. The detected harmonic-power characteristic agrees well with that predicted by the theory for local harmonic generation in the upper hybrid layer. The detected harmonic wave is essentially extraordinary, but has a small ellipticity.

Particle motion in a magnetic mirror containing high-frequency short-wavelength longitudinal electric fields is followed numerically for many mirror bounce periods. It is found that while the magnetic moment undergoes large rapid changes, these fluctuations seldom imply rapid particle loss from the mirror. This behavior is shown to be completely consistent with nonlinear superadiabatic theory, wherein containment properties of the trap are affected only when particles cross isolated singular surfaces in phase space.

The recurrence time of ion acoustic waves in a plasma has been obtained, as a function of the parameters describing the plasma, on the basis of the Korteweg—de Vries (KdV) equation and Whitham's extended KdV equation. Direct numerical solutions of the ionic Vlasov equation have also been obtained which quantitatively confirm the predictions of the KdV equation.

Critical behavior and exponents above the $\lambda$-transition points in charged and neutral Bose systems are examined with emphasis on the correlation of density fluctuations. Exponents are calculated with Wilson's expansion methods for arbitrary $d \mathrm{to} O\left(\frac{1}{m}\right)$, where $d$ is the dimension and $m$ the number of components of the Bose field. Some results for arbitrary $m \mathrm{to} O\left({\epsilon }^2\right)(\epsilon =4-d)$ are also obtained.

By means of simple model equations the mode coupling between linearly unstable and stable waves is investigated. A sharp relaxation oscillation, damped either in the presence of spontaneous emission, or by a quasilinear reduction of the growth rate, is found. Effects of external modulation of the growth rate are investigated. The final saturation level exhibits two-threshold behavior as a function of the growth rate.

Structures are observed in the current-voltage characteristics of a type-II superconductor in crossed fields. This effect can be explained as due to coherent quasiparticle excitation when the electromagnetic fields satisfy excitation conditions.

New measurements on $\beta$-brass reveal an anomaly in the thermopower in the vicinity of the order-disorder phase transition. A simple analysis, which is applicable to a wide class of phase transitions, suggests that the anomaly arises from the scattering of conduction electrons from short-range critical fluctuations and that the thermopower can, in principle, provide a direct measure of correlation functions.

The phenomenon of boson echoes, which presents some similarities with the spin-echo phenomenon, is explained in terms of phonons. In particular, the nature of the two relaxation times $T_1$ and $T_2$ is explored, and they are ascribed to anharmonic and impurity scattering processes, respectively.

We observed for the first time the transmission of electron spin resonance through a thin copper foil implanted with Mn on either one or both sides at a dose of about ${10}^{15}$ ${\mathrm{i}\mathrm{o}\mathrm{n}/\mathrm{c}\mathrm{m}}^2$. We found an increase of intensity over that of the pure metal, at 1.5°K, by a factor of 50 for one-sided-implanted samples and 2500 for two-sided-implanted samples. This enhancement decreases with increasing temperature, while the $g$ factor remains very close to that of pure copper metal.

The elastic scattering of $\alpha$ particles from ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ has been measured in the energy range between 30 and 70 MeV. A phase-shift analysis was used to investigate the even-spin, positive-parity levels in ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$ in the region between 15 and 35 MeV of excitation. New $0^{+}$ and $4^{+}$ levels have been located near 20.3 and 25.6 MeV, respectively. The positions of five $2^{+}$ levels and an additional $4^{+}$ level are compared with previous work and with theoretical predictions based on the intermediate-coupling shell model.