We report measurements of total lifetime and e-h pair density of electron-hole liquid in Ge under $〈111〉$ uniaxial stress. We show that the density dependence of electron-hole correlation can be estimated semiquantitatively from our data. Our result gives the first experimental evidence that electron-hole correlation increases rapidly as the e-h pair density is lowered. We compare our results with calculations based on different many-body theoretical approximations.

Crystals of a nearly one-dimensional salt, CsMn${\mathrm{Br}}_3$, which have been doped with trivalent neodymium, exhibit emissions from both ${\mathrm{Nd}}^{3+}$ and ${\mathrm{Mn}}^{2+}$. At room temperature the emission from ${\mathrm{Nd}}^{3+}$ is strikingly intense, much stronger than the ${\mathrm{Mn}}^{2+}$ emission. It appears that the manganese excitation migrates rapidly along the anionic chains in CsMn${\mathrm{Br}}_3$ and is trapped by the ${\mathrm{Nd}}^{3+}$ impurities. As the temperature is lowered, the rate of energy migration decreases and the ${\mathrm{Mn}}^{2+}$ emission grows at the expense of the ${\mathrm{Nd}}^{3+}$ emissions. There appears to be little energy transfer below 40 K.

Results from current-algebra calculations with symmetry breaking arising from quarkmass terms are shown not to be inconsistent with the experimental features of ${\eta }^{\prime }\to \eta \pi \pi$ decay.

We present a set of rotationally invariant observables which characterizes the "shapes" of events, and is calculable in quantum-chromodynamics perturbation theory for final states consisting of quarks and gluons ($G$). We include the effects of fragmentation to hadrons in comparing the shapes of events from the processes $e^{+}{e}^{-}\to q\overline{q}$, $e^{+}{e}^{-}\to q\overline{q}G$, and $e^{+}{e}^{-}\to \mathrm{heavy}\mathrm{resonance}\to \mathrm{GGG}$, and from heavy-quark and lepton production. We indicate how our analysis may be extended to deep-elastic lepton-hadron interactions and hadron-hadron collisions involving large transverse momenta.

An experimental measure is presented for a precise test of quantum chromodynamics. This measure involves the asymmetry in the energy-weighted opening angles of the jets of hadrons produced in the process $e^{+}{e}^{-}\to \mathrm{hadrons}$ at energy $W$. It is special for several reasons: It is reliably calculable in asymptotically free perturbation theory; it has rapidly vanishing (order $\frac{1}{W^2}$) corrections due to nonperturbative confinement effects; and it is straightforward to determine experimentally.

The first observation of the double-charge-exchange reaction (${\pi }^{-}, {\pi }^{+}$) to discrete nuclear states is reported. The mass of ${}_{}{}^{18}{}_{}{}^{}\mathrm{C}$ has been measured using the reaction ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}({\pi }^{-}, {\pi }^{+}){}_{}{}^{18}{}_{}{}^{}\mathrm{C}$ at $T\left(\pi \right)=164\mathrm{}$ MeV. The reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({\pi }^{-}, {\pi }^{+}){}_{}{}^{12}{}_{}{}^{}\mathrm{Be}$, with known $Q_0=-25.078\mathrm{}\left(15\right)\mathrm{}$ MeV, was used as the calibration reaction to obtain $Q_0=-25.69\mathrm{}\left(15\right)\mathrm{}$ MeV for the reaction ${}_{}{}^{18}{}_{}{}^{}\mathrm{O}({\pi }^{-}, {\pi }^{+}){}_{}{}^{18}{}_{}{}^{}\mathrm{C}(\mathrm{g}.\mathrm{s}.\mathrm{})$. The mass excess of ${}_{}{}^{18}{}_{}{}^{}\mathrm{C}$ is thus found to be 24.91(15) MeV.

We present evidence of an intensity interferometric effect of identical pions in relativistic nuclear collisions. From the observed correlation, we determine the space-time structure of the pion-emitting source.

We consider a model designed to describe the interaction between the conduction electrons and the localized configurational excitations (tunneling states) in metallic glasses. We show that this interaction is dominated by an infinite sequence of Anderson overlap catastrophies. Using perturbation theory and scaling arguments we analyze the low-temperature behavior of the model.

We report results from x-ray experiments on mixtures of N-($p$-hexyloxybenzylidene)-$p$-aminobenzonitrile (HBAB) in N-$p$-cyanobenzylidene-$p$-$n$-octloxyaniline (CBOOA); very recent microscopic observations on mixtures of cyanohexyloxybiphenyl in cyanooctyloxy-biphenyl are in agreement with these results. The evidence suggests that the reentrant nematic phase is similar to the classical nematic phase but may coexist with crystalline fluctuations.

Measurements of energy-resolved field emission from W(100) show that the surface resonance can exist even in the presence of adsorbed Au and Cu. A cyclical pattern is seen in which the resonance exists only at 0, 1, and 2 monolayers of coverage. A model relating these results to the symmetry of the top partial layer is proposed.

It is shown that well-known coupling of electric fields to pairs of spin operators leads to the possibility of studying certain response functions of interest in critical phenomena by means of inelastic-light-scattering experiments.

The x-ray-photoemission-spectroscopy core-level spectrum for CO chemisorbed on Cu(100) is calculated with the transfer of screening charge to the adsorbate taken into account. Using a realistic substrate density of states, we obtain the observed three-peak structure and give a simple interpretation of the results.

Electron lifetime effects on several basic physical parameters of $A15\mathrm{}$ and bcc materials are calculated using theoretical band structures and observed electrical resistivities. Notable changes in properties result from resistivities accessible thermally or by induced defects.

In ${\mathrm{Mo}}_3$Ge, an $A15\mathrm{}$ superconductor with a low transition temperature of 1.45 K, $T_c$ is found to increase with increasing disorder. We also find that the density of states increases as $T_c$ increases. The transport properties indicate an "ideal" $T^5$ behavior with Matthiessen's rule being approximately obeyed, for small amounts of damage. For larger amounts of damage, saturation is found in the transport properties even though $\lambda$, the electron-phonon coupling, increases as is evidenced by the increasing $T_c$.

Conduction electrons injected from a ferromagnet $F$ into a normal metal $M$ can be experimentally distinguished from the intrinsic conduction electrons of $M$. They contribute to the anomalous Hall conductance in $M$, which allows a direct observations of their propagation in $M$. I develop a theory of this effect and apply this new method to quench-condensed In.

We calculate the equation of state for hot dense matter and discuss implications for stellar collapse.

We have determined a new Rydberg value, $R_{\infty }=109\mathrm{}737.31476\left(32\right)\mathrm{}$ ${\mathrm{cm}}^{-1\mathrm{}}$, from an absolute wavelength measurement of the $2S_{\frac{1}{2}}-3\mathrm{}{P}_{\frac{1}{2}}$ component of the hydrogen Balmer-$\alpha$ line. Polarization spectroscopy of a mild helium-hydrogen discharge with a cw dye laser provided a threefold higher accuracy than the only previous Doppler-free measurement. Another twofold improvement can be obtained by a more precise wavelength measurement of a near-coincident ${}_{}{}^{127}{}_{}{}^{}\mathrm{I}_2^{}{}_{}{}^{}$ reference line.

Compound-nucleus cross sections from heavy-ion reactions are here parametrized by two terms: one for the compound nucleus and one for the entrance channel. The former is simply based on ${A_{\mathrm{cn}}}^{\frac{1}{3}}$; the latter involves the tails of the nuclear charge-density distributions for the projectile and target. Excellent agreement is obtained with a wide range of experimental excitation functions. No parameter adjustments, even between the lightest and heaviest systems, are necessary.

We study a model of a deformed nucleus in which protons and neutrons are described as interacting rigid rotors with axial symmetry. The nucleus as a whole is no longer axially symmetric. A magnetic-dipole collective state describing rotational oscillations of protons against neutrons is predicted.

An energy-weighted sum rule for magnetic multipole transitions $M\lambda$ is proposed as a generalization of the Kurath sum rule. The role of the spin-orbit potential is discussed, and corrections due to nuclear interaction are calculated explicitly using Skyrme forces. It is shown that, while for $\lambda =1\mathrm{}$ the whole contribution comes from spin-orbit potential, for $\lambda >1\mathrm{}$ the main part is due to the kinetic energy.