We report on inclusive hadron production in $e^{+}{e}^{-}$ annihilation at $〈s〉=53\mathrm{}$ Ge${\mathrm{V}}^2$, using a small solid-angle magnetic spectrometer with good particle identification at 90° to the beams at SPEAR II. The cross sections of ${\pi }^{\pm }$ and $K^{\pm }$ when compared with data at $s=23\mathrm{}$ Ge${\mathrm{V}}^2$ exhibit scaling in $\left(\frac{s}{\beta }\right)\frac{d\sigma }{\mathrm{dx}}$ with $x=\frac{2E}{s^{\frac{1}{2}}}$. The invariant cross section depends on the momentum as $p^{-4\mathrm{}}$.

The reaction $e^{+}{e}^{-}\to {\mu }^{+}{\mu }^{-}$ has been measured in the center-of-mass energy range 5.8-7.4 GeV. The polar-angle asymmetry agrees with second-order quantum electrodynamics. From this a 95% confidence limit of $M_Z>\frac{53g_a}{e}$ GeV is placed on the mass to coupling constant ratio for a neutral vector boson.

The nonlinear realization of supersymmetry of Volkov and Akulov is related to a constrained linear realization in two and four dimensions.

A recently developed technique enables one to measure the relative sign of inelastic proton-channel amplitudes of resonances. Using this we have measured signs of 32 fine-structure levels in the vicinity of the ${\frac{3}{2}}^{-}$ analog state seen in the reaction ${}_{}{}^{44}{}_{}{}^{}\mathrm{Ca}$+$p$ at $E_p=2.6\mathrm{}$ MeV. Thereby we construct a new type of datum, "the off-diagonal strength function," and compare this with the prediction made by the theory of analog-state broadening. This prediction involves no unknown parameters, and so the degree of fit provides an excellent test of the theory.

The possible manifestations of an oblate-shape region at high spin in $A=160-180\mathrm{}$ nuclei are considered. We focus attention on the fact that rotational band phenomena indeed can exist in nuclei with oblate shapes. From estimates of transition energies, the yrast cascade there could consist largely of low-energy, alternating $M1\mathrm{}$ transitions within bands and $E2\mathrm{}$ transitions between bands. If the recently found stretched-dipole transitions are confirmed as $M1\mathrm{}$, these results may be an indication for the existence of oblate shapes at high spin.

Isotopes of ${}_{}{}^{123-137}{}_{}{}^{}\mathrm{Cs}$ produced by spallation of lanthanum and separated in mass by the ISOLDE on-line facility have been transformed into an atomic beam which is illuminated with a tunable cw dye laser. From the sensitive detection of the optical resonance lines at 459 nm, the hyperfine structure of ${}_{}{}^{123-132}{}_{}{}^{}\mathrm{Cs}$, ${}_{}{}^{137}{}_{}{}^{}\mathrm{Cs}$, and ${}_{}{}^{130m}{}_{}{}^{}\mathrm{Cs}$ has been determined. The interpretation of isotope shifts, in terms of variation of charge radii, is discussed.

Differential cross sections and analyzing power for reactions ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}(p,{\pi }^{+})$ and ${}_{}{}^9{}_{}{}^{}\mathrm{Be}(p,{\pi }^{+})$ leading to discrete final states in the residual nuclei have been measured in the angular range from 35° to 135° using 200-MeV polarized protons. The shape of the angular distribution of analyzing powers is essentially independent of the residual nuclear state, indicating a strong dependence upon reaction mechanism rather than nuclear structure.

The cross sections for the fusion of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ with the spherical and deformed isotopes of Sm measured at bombarding energies spanning the fusion barrier indicate the importance of nuclear deformation for the fusion process. Calculations based on the usual static treatment of deformation effects, however, show significant discrepancies with the experimental data.

Radiochemically determined cross sections $\sigma (Z, A)$ were used to construct charge and mass distributions for the reaction of 1785-MeV ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ ions with thick ${}_{}{}^{238}{}_{}{}^{}\mathrm{U}$ targets. Fission of the colliding nuclei is found to dominate. For the surviving uraniumlike fragments an enhancement of yields compared to the Kr + U and Xe + U reactions is observed. The formation of heavy actinides is shown to be associated with the low-energy tails of the broad excitation energy distributions in damped collisions.

This Letter reports the first experimental observation of population inversion of a two-photon transition in N${\mathrm{H}}_3$ using the adiabatic rapid-passage technique. The population inversion was demonstrated by the observation of stimulated two-photon gain and emission. By use of this technique, the two-photon population relaxation time $T_1$ was measured.

This paper outlines a scheme employing magnetically compressed ion rings for the transport of energy to a deuterium-tritium pellet.

The mobilities of positive and negative ions have been measured in the normal phase of a ${}_{}{}^3{}_{}{}^{}\mathrm{He}$-${}_{}{}^4{}_{}{}^{}\mathrm{He}$ mixture near the tricritical point. Whereas for negative ions nearly the same weak temperature dependence in observed as in pure ${}_{}{}^3{}_{}{}^{}\mathrm{He}$, the mobility of positive ions in the mixture drops sharply by almost a factor of 2 when phase separation is approached. This is attributed to condensation of ${}_{}{}^4{}_{}{}^{}\mathrm{He}$ onto the positive-ion surface.

Our measured ranges of 600-MeV/amu ${}_{}{}^{56}{}_{}{}^{}\mathrm{Fe}$ ions in a variety of substances are shorter than predicted by the standard Bethe stopping-power theory and are consistent with values computed using high-order corrections to the Mott cross section.

X-ray studies of tetrathiafulvalenium-thiocyanate [TTF${\mathrm{}\left(\mathrm{SCN}\right)\mathrm{}}_{0.588}$] show a Peierls instability with one-dimensional charge-density waves near 300 K followed by three-dimensional order at $T_c=180\mathrm{}$ K. Below $T_c$, an interchain competition between both elastic forces and Coulomb interactions drives a temperature-dependent monoclinic strain. A Landau theory including both charge-density and strain order parameters describes the relative TTF chain slip and the superlattice phase variation.

Measurements of the NMR susceptibility of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ in Grafoil indicate that the surface layer exhibits a Curie-Weiss magnetization tending towards ferromagnetism. The surface magnetization has a magnitude approximately equivalent to the number of spins in one monolayer. At temperatures between 0.43 and 1 mK the susceptibility has a strong magnetic field dependence. The data are consistent with a simple Landau-Ginzburg model indicating a phase transition at 0.38 mK with a lower than expected magnetization.

Pulsed NMR measurements of the susceptibility and the transverse and longitudinal relaxation times of ${}_{}{}^3{}_{}{}^{}\mathrm{He}$ intermixed with 9 nm of carbon particles have been performed down to 0.4 mK. The results indicate that the first atomic layer has an antiferromagnetic exchange interaction. The intermediate solid-liquid region, ∼5 atomic layers thick, favors ferromagnetism and approaches a ferromagnetic transition at the lowest temperatures.

We calculate the attenuation of zero sound due to fluctuations of the superfluid order parameter above $T_c$. The results appear to account for the excess attenuation recently observed by Paulson and Wheatley.

We present a general approach for applying real-space renormalization-group methods to dynamic critical phenomena. In particular, we discuss the two-dimensional kinetic Ising model treating the interaction between blocks of spins as a small parameter.

EXAFS (extended x-ray-absorption fine structure) spectra of Cu${\mathrm{Br}}_2$ aqueous solutions at various concentrations have been analyzed both for Br and Cu $K$ edges. They show a local ordering of the Cu and Br ions in planar structure which spreads as the concentration is increased up to saturation. Our data give a direct confirmation of the local-ordering model proposed recently on the basis of Raman and viscosity measurements.

An $s-p$—like intrinsic surface state on Ni(111) has been found which has an energy of $E_i=-0.25\mathrm{}$ eV relative to the Fermi energy at $\overline{\Gamma }$ and lies between the $L_3$ ($E_i\simeq -0.15\mathrm{}$ eV) and ${L_2}^{\prime }$ ($E_i=-0.9\mathrm{}$ eV) bulk states. Its momentum dispersion ($E$ vs ${\overrightarrow{\mathrm{k}}}_{\parallel }$) and $h\nu$-dependent photoionization cross section have been determined using angle-resolved photoemission with synchrotron radiation. The existence of this state significantly affects spin-polarized photoemission, chemisorption, band-structure, and exchange-splitting interpretations for Ni.