The results of an experiment to observe the nonlinear conversion of second sound to first sound within a waveguide show that this resonant process occurs at precisely the predicted frequency. Unique procedures are used to calibrate the first-sound transducers and we find the amplitude of the mode-converted first sound has its predicted value value which is determined principally by $\frac{\partial \rho }{\partial \left(w^2\right)}$ where $w$ is the difference between the normal-fluid and superfluid velocities and $\rho$ is the density.

If a pulse of light is transmitted through a slab of material whose polariton dispersion curve has a minimum value for the group velocity [$\omega \mathrm{}\left(q\right)\mathrm{}$ has an inflection point], then the intensity of emergent light will oscillate before decaying, in accordance with the properties of the Airy function. The effect is linear in the applied field of the incident light. Application is made to the $A(n=1\mathrm{})\mathrm{}$ exciton-polariton of CdS, with no adjustable parameters.

The temperature dependence of the longitudinal relaxation time of positive-muon spin in paramagnetic MnO has been determined by measuring the ${\mu }^{+}-e^{+}$ forward/backward asymmetry. The relaxation time, $T_1=2.00\mathrm{}$ μsec at 124 K can be accounted for in terms of exchange-fluctuating ${\mathrm{Mn}}^{++}$ atomic dipolar fields; the increase of $T_1$ with temperature shows that the relaxation is further slowed by fast diffusional motion of the ${\mu }^{+}$.

The dependence on hydrostatic pressure of the superconducting transition temperature $T_c$ of a nontransforming ${\mathrm{V}}_3$Si single crystal is determined to 45 kbar with use of a newly developed pressure cell. A clear break in the slope $\frac{d{T}_c}{\mathrm{dP}}$ at 32 kbar supports the existence of the pressure-induced structural phase transition predicted by Larsen and Ruoff.

Resistivities of thin-film Cs-based alloys prepared by coevaporation at He temperature reveal charge transfer to high-valence impurities. Percolative transitions to new disordered insulating phases occur as the impurity content is increased. Metallic components of resistance exceeding 3×${10}^4$Ω are observed near the percolation thresholds.

We present first-principles calculations of the electron-phonon parameters which govern transport and superconductivity in Pd. Our calculated resistivity is in good agreement with experiment. The "$s$-wave" coupling constant (or mass enhancement) is 0.41 and the "$p$-wave" coupling constant is 0.002, making the existence of observable electron-phonon-induced "$p$-wave" pairing in Pd very doubtful.

Data from the reaction ${\pi }^{-}p\to n{K_s}^0{K_s}^0$ have been used to determine the cross section for the reaction ${\pi }^{+}{\pi }^{-}\to {K_s}^0{K_s}^0$ by extrapolation to the pion pole. The reaction ${\pi }^{+}{\pi }^{-}\to {K_s}^0{K_s}^0$ is dominated by $S^{*}$ and $f^0$ production. The ${\pi }^{+}{\pi }^{-}\to {K_s}^0{K_s}^0$ cross section is well below the $S$-wave unitarity limit in the $S^{*}$ (threshold) region. We discuss implications for the SU(3) scalar meson nonet and for $\pi \pi$ phase-shift analyses.

A search for the three-photon decay of the neutral pion has been conducted using fast counter techniques. Such a decay would indicate a violation of charge-conjugation invariance. No excess of signal over background was observed, providing an upper limit to the branching ratio of 1.5 × ${10}^{-6\mathrm{}}$ at 90% confidence level.

We show, by explicit construction of a highly convergent superweak theory of $\mathrm{CP}$ nonconservation, that the problem of natural suppression of strong $P$ and $T$ noninvariances—in the presence of instantons—may be resolved without invoking symmetries which imply massless quarks or nearly massless bosons.

I suggest that the dominance of matter over antimatter in the present universe is a consequence of baryon-number-nonconserving reactions in the very early fireball. Unified guage theories of weak, electromagnetic, and strong interactions provide a basis for such a conjecture and a computation in specific SU(5) models gives a small ratio of baryon- to photon-number density in rough agreement with observation.

Average multiplicities and pseudorapidity distributions for 100-GeV/c $p$-, $K^{+}$-, and ${\pi }^{+}$-nucleus collisions are presented. The average multiplicities increase with nuclear thickness. The fractional increase is independent of incident particle species, provided that nuclear thicknesses are calculated in units of mean free path of the incident hadron. This scaling behavior suggests that the immediate product of a hadron-nucleon collision is a state similar to the incident hadron.

Measurement of $e^{+}{e}^{-}\to \gamma \nu \overline{\nu }$ at the new colliding-beam facilities can determine directly the total number of neutrino types (${\nu }_e$, ${\nu }_{\mu }$, ${\nu }_{\tau }$, etc.).

A search for the lowest $2^{+}$ state in ${}_{}{}^{146}{}_{}{}^{}\mathrm{Gd}$ using ($\alpha$,$2n\gamma$) excitation function measurements near threshold has located that state at 1971 keV. Its energy, more that 300 keV higher than in any other $N=82\mathrm{}$ nucleus, provides clear spectroscopic evidence for a large gap in the single-particle spectrum at $Z=64\mathrm{}$.

A number of narrow lines are observed around 20 MeV excitation energy in ${}_{}{}^{207}{}_{}{}^{}\mathrm{Pb}$ in the study of ${}_{}{}^{208}{}_{}{}^{}\mathrm{Pb}$(${}_{}{}^3{}_{}{}^{}\mathrm{He}$,$\alpha$) at 70 MeV. Their excitation energies and relative spacing suggest that these peaks arise from the neutron pickup from the inner filled sdhg shell between magic numbers 82 and 50 with isospin number $T=\frac{45}{2}$. In addition, distorted-wave Born-approximation (DWBA) calculations of the angular distributions agree in shape with the data. The solution of the Lane coupled-channels equations leads to a DWBA cross section in reasonable agreement with experiment.

The quantal fluctuations in energy loss, scattering angle, and angular momentum transfer in heavy-ion collisions due to the excitation of surface modes is studied in a classical model by utilizing a distribution of shapes, representing the zero-point fluctuations as initial conditions. For grazing impact parameters this leads to a clear separation between deep-inelastic and quasielastic events.

The coefficient ${\alpha }_{+}$ of the alignment-positron-momentum correlation in the decay ${}_{}{}^{12}{}_{}{}^{}\mathrm{N}$ → ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$(g.s.) has been determined using the technique of spontaneous level mixing. We find ${\alpha }_{+}=-2.73\mathrm{}\left(39\right)/\mathrm{GeV}$; this agrees with the revised result of Sugimoto et al. The two coefficients ${\alpha }_{\pm }$ jointly yield [assuming strong conservation of vector current (CVC)] ${F_E}^{\mathrm{}\left(2\right)\mathrm{}}$ $F_A=-\frac{0.13\left(48\right)\mathrm{}}{2M}$, i.e., provide strong evidence against a second-class axial current in a model-independent way. Conversely, assuming ${F_E}^{\mathrm{}\left(2\right)\mathrm{}}\equiv 0$ yields $\frac{F_M}{F_A}=\frac{3.93\left(48\right)\mathrm{}}{2M}$, in excellent agreement with the CVC prediction.

The absorption line shape of Cs-Ar system is recorded using two-photon ionization of the system with $\mathrm{Cs}\mathrm{}\left(7P\right)\mathrm{}$ as an intermediate state. New satellite structures in the wings of $\mathrm{Cs}\mathrm{}\left(7P\right)\mathrm{}$ are observed which were not resolved in previous absorption measurements. Also the absolute absorption cross section in the blue wing is measured.

We have used a pair of simultaneously pumped dye lasers to produce in Na vapor the sum-frequency two-photon analog of the photon echo. Quantum-beat effects were observed. Relaxation of the $3{}_{}{}^2{}_{}{}^{}S_{\frac{1}{2}}^{}{}_{}{}^{}-4\mathrm{}{}_{}{}^2{}_{}{}^{}D_{\frac{3}{2}}^{}{}_{}{}^{}$ superposition was measured.

An Auger variant of the x-ray-absorption fine-structure (EXAFS) technique has been successfully applied to study the adsorption site and adsorbate-substrate bond length in a single-crystal system. The surface-EXAFS technique should have widespread applications in surface crystallographic studies.

We have carried out computer simulations of the dynamics of a model polymer chain in a solvent. We find that the structure function scales for different chain sizes $N$ as a function of $q=k{N}^{\nu }$ with $\nu =0.6\mathrm{}$ ≃ exponent for the radius of gyration. Furthermore, $S\left(q\right)\mathrm{}\sim q^{-\frac{5}{3}}$ over a wide range, as predicted by Edwards. Time-dependent correlation functions appear to scale as $t{N}^{\alpha }$, with $\alpha \simeq 2\nu +1\mathrm{}$. The time-displaced structure function is of the form $S(k{N}^{\nu },t{N}^{\alpha })$.