We examine some features of neutron-proton elastic-scattering data over the laboratory momentum range 4.5 to 12.5 GeV/c. Comparisons with proton-proton elastic scattering data and with theory are made in both the small- and the large-angle-scattering regions.

At a square of the momentum transfer of 1.0 ${(\mathrm{G}\mathrm{e}\mathrm{V}/\mathit{c})}^2$ the elastic scattering of electrons on deuterons has been measured at electron scattering angles of 8°, 60°, and 82°. From these data we have extracted a value of $B\left(q^2\right)=(0.59\mathrm{}\pm 1.20)\times {10}^{-5\mathrm{}}$ for the deuteron. This measurements extends the range in momentum transfer by almost a factor of 2 over the previous measurements.

Inclusive $\gamma$-ray spectra from $\psi \mathrm{}\left(3095\right)\mathrm{}$ and ${\psi }^{\prime }\mathrm{}\left(3684\right)\mathrm{}$ decays have been observed with segmented arrays of NaI(Tl) in an $e^{+}{e}^{-}$ colliding-beam experiment. Three major peaks are seen in the ${\psi }^{\prime }$ spectrum corresponding to ${\psi }^{\prime }\to \chi \gamma$ with $m_{\chi }=3561, 3511, \mathrm{and} 3413$ MeV/${\mathit{c}}^2$ and with branching fractions of (7.0±2.0), (7.1±1.9), and (7.2±2.3)%, respectively. Enhancements in the ${\psi }^{\prime }$ spectrum at higher energies are consistent with decays $\chi \to \psi \gamma$. The $\psi$ spectrum shows no statistically significant structure.

Recent improvement in electron-beam resolution has made possible the direct study of isotope effects in differential cross sections in ${\mathrm{H}}_2$ and ${\mathrm{D}}_2$. The observation of the reduced-mass dependence (${\mu }^{-\frac{1}{2}}$) of vibrational ($v=0\mathrm{}\to 1$) cross sections and isotopic independence of rotational cross sections at 4 eV has been understood using the frame-transformation theory. Generalization and limitation of the theory are discussed. Specific predictions are made for cross sections in HD, HT, DT, and ${\mathrm{T}}_2$.

We present results of a large-acceptance experiment in which muon pairs were observed in the mass range 0.6 to 6.0 GeV/${\mathit{c}}^2$. Emphasis is given to features of the production of $\frac{J}{\psi }$ and ${\psi }^{\prime }\mathrm{}\left(3.7\right)\mathrm{}$ particles. We find $\frac{{\left[B\sigma \right]}_{{\psi }^{\prime }\mathrm{}\left(3.7\right)\mathrm{}}}{{\left[B\sigma \right]}_{\frac{J}{\psi }}}$ to be 0.007±0.004 for $p$-C and 0.018±0.007 for ${\pi }^{+}$-C interactions. Comparison with results from $e^{+}{e}^{-}$ storage rings indicates that both the $\frac{J}{\psi }$ and the ${\psi }^{\prime }\mathrm{}\left(3.7\right)\mathrm{}$ are produced strongly rather than electromagnetically in our experiment.

Data from a study of muon pairs produced in hadron-nucleus collisions are compared with the Drell-Yan model. Comparison of dimuon production by ${\pi }^{+}$ and ${\pi }^{-}$ mesons on an isoscalar target shows evidence for a charge asymmetry characteristic of an isospin-nonconserving electromagnetic process. The average transverse momentum of the pairs increases smoothly with pair mass. Data taken on carbon and tin targets are used to extract the dependence on target atomic weight.

I show that the shapes of the differential cross sections for the "backward" production of high-energy particles ($p, d, t, \dots , {\mathrm{B}}^{11}$), by projectiles of various types ($p, d, \alpha$), from nuclei of any $A$ (Be,...,U), and for a large range of incident momenta and backward angles, can be related by quasi-two-body kinematics. This permits the direct determination of the shape of the momentum distribution of high-momentum nucleons in nuclear matter. This distribution is shown to be $F\left(k\right)=\frac{\exp (-\frac{k}{k_0})}{k}$ over the range 0.4 to 1.5 GeV/c.

The excitation functions of the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$, ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$(g.s.)) ${}_{}{}^8{}_{}{}^{}\mathrm{Be}$(g.s.) were measured at 35° lab (∼90° c.m.) and at 20° lab (∼50° c.m.) near and above the Coulomb barrier ($5.75<~E_{\mathrm{c}.\mathrm{m}.\mathrm{}}<~8.9$ MeV). Resonant structures were found at 5.94, 6.35, 6.69, 8.0, and 8.4 MeV. These resonant structures were correlated with those in the elastic channel. The angular distributions at 6.4, 6.65, and 8.0 MeV were measured, and the spin-parity assignments are $2^{+}$, $2^{+}$, and $4^{+}$, respectively. The oxygen partial width at 5.94 MeV was determined to be 14 keV, which is as large as the carbon partial width.

High-resolution neutron transmission and elastic-scattering measurements on ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ have revealed a concentration of $p$-wave strength in ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$ which is mainly accounted for by $J^{\pi }=1^{+}$ resonances. The sum of the ground-state radiative widths for these resonances is $\Sigma {\Gamma }_{\gamma 0}=7.2\mathrm{}$ eV which agrees well with a one-particle-one-hole theoretical prediction which locates a fragment of the giant $M1\mathrm{}$ resonance at 7.50 MeV with ${\Gamma }_{\gamma 0}=9.3\mathrm{}$ eV.

The nuclear shell model with a second-order effective Hamiltonian derived within Brueckner theory from the free nucleon-nucleon interaction is shown to yield accurate binding energies of nuclei with $16<A<\mathrm{}40\mathrm{}$. This agreement is obtained by choosing the spectrum of low-lying unoccupied orbitals in a justified manner and, when necessary, by employing a statistical method to approximate the lowest eigenvalue of very large shell-model diagonalizations.

We report an experimental check of the Mie-Debye theory for the variation of radiation pressure on dielectric spheres with wavelength and size using optical-levitation techniques. Sharp resonances are observed which are shown to be related to dielectric surface waves. They permit particle-size measurement to a precision of 1 part in ${10}^5$ to ${10}^6$.

For a broad $\overrightarrow{\mathrm{k}}$ spectrum, the collisionless tearing mode grows linearly until the Landau electrons become magnetized by the wave field. The electrons then spatially diffuse as a result of turbulent magnetic-gradient drifts which leads to a nonlinearly enhanced growth rate. At large amplitudes the nonlinear growth rate is dominated by ions.

Several lines of O viii have been investigated during the injection of hydrogen atoms at energies of 10, 15, and 30 keV into the Oak Ridge tokamak (ORMAK). The Lyman-$\alpha$, -$\beta$, and -$\gamma$ lines and the Balmer-$\beta$ line exhibit slowly increasing signals, but the intensity of the Balmer-$\alpha$ line increases sharply as soon as injection begins. This prompt signal is interpreted to be the direct result of charge transfer from hydrogen to ${\mathrm{O}}^{7+}$ ions in excited states.

By use of extended x-ray absorption fine structure, the Ag ions in superionic AgI are shown to occupy the distorted tetrahedral sites in the iodine bcc lattice, being slightly displaced from the center toward the faces along the most probable diffusion path. The residence time of the Ag ions in these sites is determined to be longer than their flight time, implying that the jump-diffusion model is more appropriate than a free-diffusion model.

The energy theorem of electrodynamics is cast in a form which yields expressions for the energy current and energy dissipation of a combined field of transverse and longitudinal waves when the longitudinal field is described in the hydrodynamic approximation. This has consequences concerning the boundary conditions for transverse and plasma waves at metal-metal interface and the photoemission yield.

A new detector for cosmic-ray electrons, consisting of a combination of a transitionradiation detector and a shower detector, has been constructed, calibrated at accelerator beams, and exposed in a balloon flight under 5 g/${\mathrm{cm}}^2$ of atmosphere. The design of this instrument and the methods of data analysis are described. Preliminary results in the energy range 9-300 GeV are presented. The energy spectrum of electrons is found to be significantly steeper than that of protons, consistent with a long escape lifetime of cosmic rays in the galaxy.

Black holes are shown to obey the principles of irreversible thermodynamics in the form of a fluctuation-dissipation theorem for their zero-point quantum fluctuations. Moreover Hawking radiation is shown to be related to the macroscopic radiation of a nonstationary black hole in accordance with Onsager's principle.

An operator renormalization transformation is proposed for quantum spin systems which is manifestly basis independent and preserves the fundamental symmetries of the spin Hamiltonian. We develop a cumulant expansion suitable for noncommuting operators and illustrate the general techniques with several sample calculations.

Integration of Einstein's inertial-mass induction to the particle horizon in Robertson-Walker space yields an equation for the scale factor of the universe. A generalized Milne-McCrea theorem is used, and $G$ is allowed to vary slowly in order to preserve the weak equivalence principle. Among the results given is that at the present time $\frac{d\left(\frac{G}{G_0}\right)}{\mathrm{dt}}=-0.22\mathrm{}{H}_0$ for $q_0=0.03\mathrm{}$. The age is somewhat less than for Friedman models. These results differ minimally from general relativity.

We describe an extension of the gauge theory of weak and electromagnetic interactions to SU(3) ⊗ U(1). The extended theory naturally insures universality, absence of right-handed currents in $\beta$ and muon decay, flavor conservation in neutral currents, etc.; gives good quantitative agreement with observations of neutral currents; and accounts for recently observed trimuon events.