We predict the mass spectrum of the $2{}_{}{}^3{}_{}{}^{}S_1^{}{}_{}{}^{}$, $J^{\mathrm{PC}}=1^{--}$ vector mesons, the $D^{*}-D^{*\prime }$ mixing angle, and the $F^{*}-F^{*\prime }$ mixing angle (defined to be equal to the $D^{*}-D^{*\prime }$ mixing angle) in a nonperturbative approach to broken SU(4) symmetry.

We report measurements of the polarization parameters in ${\pi }^{+}p$ and ${\pi }^{-}p$ elastic scattering at an incident momentum of 100 GeV/c. The results cover the range $0.18<~-t<~1.4$ Ge${\mathrm{V}}^2$ and are in agreement with current Regge-model predictions.

The second-quantized Coulomb-gauge Hamiltonian for any nonrelativistic system of fermions minimally coupled to non-Abelian gauge fields is derived by performing successive non-Abelian Foldy-Wouthuysen transformations. In this general formalism, a detailed analysis is made of threshold fermion-antifermion bound states in the weak-coupling limit and the form of the two-loop nonrelativistic Bethe-Salpeter kernel is determined. This kernel gives a static potential independent of the fermion mass, but only for singlet states of the gauge group.

Target-residue mass and charge distributions have been measured for 76 products of the interaction of 25.2-GeV ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ with U. The mass yield curve shows two prominent bumps: one for $80<~A<~145$ resulting from the modest excitation-energy (50-100 MeV) fission of a species with $A\sim 225$, and the second for $160<~A<~190$ apparently due to the survivors of a more central collision between projectile and target.

Polarization of product ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$ in the reaction ${}_{}{}^{100}{}_{}{}^{}\mathrm{Mo}$(${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$, ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$)${}_{}{}^{102}{}_{}{}^{}\mathrm{Ru}$ at 90 MeV was measured as a function of product kinetic energy at the reaction angle of 20°. The polarization was found antiparallel to the vector ${\overrightarrow{\mathrm{k}}}_f\times {\overrightarrow{\mathrm{k}}}_i$ for higher-energy ${}_{}{}^{12}{}_{}{}^{}\mathrm{B}$, while parallel for those with lower energy. The zero crossing occurred at around maximum in the energy spectrum.

The static quadrupole moment $Q_{2^{+}}$ for the 1.982-MeV $2_1^{+}$ state in ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}$ has been remeasured via Coulomb excitation. Anomalously large $Q_{2^{+}}$ values previously published are shown to be erroneous as a result of Coulomb-nuclear interference and other problems eliminated by the present techniques. Both present and previous data are consistent with $Q_{2^{+}}$ values of - ${3.1}_{-2.0\mathrm{}}^{+3.0\mathrm{}}$ (- ${0.1}_{-2.0\mathrm{}}^{+3.0\mathrm{}}$) $e·{\mathrm{fm}}^2$ for constructive (destructive) interference. This result agrees with shell-model and coexistence-model predictions.

A modification of the Thomas-Fermi theory is suggested to overcome the difficulty of the classical turning point. Model calculations for the spatial density are done for neutrons moving in a harmonic oscillator and a Woods-Saxon potential. The density is reproduced reasonably well both in the surface and the tail of the distribution.

Mass-separated samples of the unstable nuclides ${}_{}{}^{128}{}_{}{}^{}\mathrm{Ba}$ ($T_{\frac{1}{2}}=2.4\mathrm{}$ d) and ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ba}$ ($T_{\frac{1}{2}}=11.5\mathrm{}$ d) have been investigated by means of Doppler-free laser spectroscopy, using cw dye lasers and a well-collimated atomic beam. From isotope shifts and hyperfine structure of the ${}_{}{}^1{}_{}{}^{}S_0^{}{}_{}{}^{}-{}_{}{}^1{}_{}{}^{}P_1^{}{}_{}{}^{}$ transition ($\lambda =553.6\mathrm{}$ nm) we obtained the differences of mean-square charge radii $\delta 〈r^2〉({}_{}{}^{131}{}_{}{}^{}\mathrm{Ba}-{}_{}{}^{130}{}_{}{}^{}\mathrm{Ba})=-0.006\mathrm{}\left(3\right)\mathrm{}$ ${\mathrm{fm}}^2$ and $\delta 〈r^2〉({}_{}{}^{130}{}_{}{}^{}\mathrm{Ba}-{}_{}{}^{128}{}_{}{}^{}\mathrm{Ba})=-0.022\mathrm{}\left(3\right)\mathrm{}$ ${\mathrm{fm}}^2$ and the magnetic moment of ${}_{}{}^{131}{}_{}{}^{}\mathrm{Ba}$, $\mu =-0.714\mathrm{}\left(6\right)\mathrm{}{\mu }_N$.

We have measured the interference between the direct and exchange scattering amplitudes in electron impact ionization of atomic hydrogen over the energy range 15 to 197 eV in a crossed-beams experiment utilizing spin-polarized electrons and spin-polarized hydrogen atoms. The experimental values for the asymmetry $A=\frac{({\sigma }^{\uparrow \downarrow }-{\sigma }^{\uparrow \uparrow })}{({\sigma }^{\downarrow \uparrow }+{\sigma }^{\uparrow \uparrow })}$ in the total ionization cross section for antiparallel and parallel incident- and atomic-electron spins are inconsistent with all theoretical calculations below 50 eV.

A magnetic field in a laser-irradiated plasma is shown to have an important effect on the resonant absorption of the laser radiation normally incident on the inhomogeneous plasma. For typical paramaters in laser-fusion experiments, the absorption coefficient is above 50% with $\alpha \equiv {\pi }^2{\left(\frac{{\omega }_c}{\omega }\right)}^2{\left(\frac{L\omega }{c}\right)}^{\frac{4}{3}}$ between 1.5 and 10 and a maximum of ∼ 70% is achieved for $\alpha =4\mathrm{}$.

Light-scattering techniques have been used to study the behavior of the antiferromagnet dysprosium aluminum garnet near its tricritical "wings." The crossover from tricritical to critical behavior near the wing critical lines has been observed, and the shape of the wing critical lines has been determined. The results are in good agreement with the present theory.

An explanation of experimental NMR relaxation times, $T_2$, for ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ adsorbed on Grafoil at coverages just greater than one monolyaer is given in terms of the dipolar interaction of first-layer particles modulated by quantum exchange of particles between first and second layers. It is found that a Heisenberg-Hamiltonian description fails and one must use an exchange operator formulation which permits transitions among second-layer $\overrightarrow{\mathrm{k}}$ states during the exchange process.

The temperature variation of the superfluid density has been measured for ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ films adsorbed on porous Vycor glass. Films with transition temperatures ranging from 0.1 to 1.5 K were studied. Apart from a small rounding on the order of $5\times {10}^{-3\mathrm{}}{T}_c$, the superfluid density of these films follows a power law near the transition similar to bulk helium.

We have carried out a high-resolution x-ray-scattering study of the critical fluctuations in the nematic phase associated with the nematic-smectic-$A$ transition in N-$p$-cyanobenzylidene-$p$-octyloxyanilene (CBOOA). It is shown that for $8\times {10}^{-5\mathrm{}}\lesssim \frac{T}{T_c}-1\mathrm{}\lesssim 2\times {10}^{-2\mathrm{}}$ the transverse and longitudinal correlation lengths diverge with identical exponents, that is, $|{\nu }_L-{\nu }_T|<\mathrm{}0.03\mathrm{}$. As one approaches $T_c$ the system appears to crossover from helium- to mean-field critical behavior at a reduced temperature of ∼${10}^{-3\mathrm{}}$.

Solid spin-aligned atomic hydrogen is shown to be unstable against spontaneous magnon creation due to electronic dipole-dipole and hyperfine interactions even at $T=0\mathrm{}$ K for magnetic fields less than $H_c\approx \frac{7.3\tilde{J}}{{\mu }_e}$, where $\tilde{J}$ is the motionally averaged exchange interaction. For an fcc crystal at 50 ${\mathrm{cm}}^3$/mole, $H_c\approx {10}^6$ G. Similar considerations apply to the fluid state where the relevant parameter is again $\tilde{J}$ which is proportional to the density in the low-density limit.

Ground-state properties and elementary excitations of superfluid spin-aligned atomic H are studied using methods adapted from the theory of liquid ${}_{}{}^4{}_{}{}^{}\mathrm{He}$. The ground state is a $k=0\mathrm{}$ condensate of the $\left|\downarrow \right(\mathrm{electron}), \uparrow (\mathrm{proton})〉$ hyperfine state with a small admixture of $|\uparrow \downarrow 〉$ due to the hyperfine interaction. Excitations can also be labeled approximately by their hyperfine states. ${\varphi }_{\downarrow \uparrow }\mathrm{}\left(k\right)\mathrm{}$ excitations are phononlike. ${\varphi }_{\downarrow \uparrow }\mathrm{}\left(k\right)\mathrm{}$ and ${\varphi }_{\uparrow \downarrow }\mathrm{}\left(k\right)\mathrm{}$ are free-particle-like with energy gaps, and ${\varphi }_{\uparrow \downarrow }\mathrm{}\left(k\right)\mathrm{}$ excitations resemble spin waves.

The enhancement of the electron diffusion thermopower due to the electron-phonon interaction is studied microscopically. I find that the thermopower is enhanced not only by the mass enhancement but also significantly by a new mechanism independent of scattering. The result is justified in terms of the Landau-Boltzmann equation.

Solutions for the nonlinear evolution of the one-dimensional space-time and two-dimensional steady-state interaction of three wave packets in an inhomogeneous medium are presented. A transformation of the nonlinear equations allows the use of an inverse scattering transform for finding exact time-asymptotic properties of the interaction. Inhomogeneity gives a decreased action transfer in both decay and backscattering, and suppresses explosive instabilities and soliton decay above a certain threshold.

We show that the total energy in supergravity theory is nonnegative. The derivation is based on the fact that for bounded systems the Hamiltonian operator is the square of the spinor supercharge just as for globally supersymmetric systems. The result holds for any of the pure, matter-coupled, or extended versions of supergravity, except those with cosmological term for which the concept of total energy does not exist.

Dimuon production is studied in 400-GeV proton-nucleus collisions. A strong enhancement is observed at 9.5 GeV mass in a sample of 9000 dimuon events with a mass $m_{{\mu }^{+}{\mu }^{-}}>5\mathrm{}$ GeV.