Collapse of polyacrylamide gels is observed upon changing temperature or fluid composition. It is explained in terms of mean-field theory based on the extension of Flory's formula for free energy of gels. Theory predicts, and I have observed, existence of a critical endpoint in the phase equilibria.

By adopting Nelson's stochastic framework of quantum mechanics (i.e., the stochastic quantization), a time-dependent description of tunneling phenomena is developed. As a simple model, tunnel effect of a one-dimensional quantum mechanical system with bistable potential is analyzed in much detail.

The complex amplitude $X_1+i{X}_2\equiv (x+\frac{\mathrm{ip}}{m\omega })e^{i\omega t}$ of a harmonic oscillator is constant in the absence of driving forces. Although the uncertainty principle forbids precise measurements of $X_1$ and $X_2$ simultaneously ($\Delta X_1\Delta X_2>~\frac{\hslash }{2m\omega }$), $X_1$ alone can be measured precisely and continuously ("quantum nondemolition measurement"). Examples are given of measuring systems that do this job. Such systems might play a crucial role in gravitational-wave detection and elsewhere.

We have observed the ${\psi }^{\prime \prime }$ resonance in the cross section for $e^{+}{e}^{-}\to \mathrm{hadrons}$ at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=3770\mathrm{}\pm 6.0$ MeV, of total width $\Gamma =24\mathrm{}\pm 5$ MeV and partial width to electron pairs ${\Gamma }_{\mathrm{ee}}=180\mathrm{}\pm 60$ eV. The cross section for hadronic events which contain anomalous electron provides both unambiguous evidence of $D$ semileptonic decays and a branching ratio measurement of (11±2)%.

We argue that confinement requires singularities in parton-hadron wave functions which are necessary for the parton-model description of physical processes and the analytic structure of hadronic amplitudes. Our arguments are supported by explicit calculations in two-dimensional quantum chromodynamics. In particular, we show, using new WKB techniques, that the amplitudes for $e^{-}h\to e^{-}X$ and $e^{+}{e}^{-}\to \mathrm{hX}$ are related by analytic continuation in their scaling regions.

The polarization of the ${\Sigma }^{+}$ has been measured for the line-reversed reactions ${\pi }^{+}p\to K^{+}{\Sigma }^{+}$ and $K^{-}p\to {\pi }^{-}{\Sigma }^{+}$ at 7 and 11.6 GeV/c using the SLAC Hybrid Facility. Since the ${\Sigma }^{+}$ decay is observed in the bubble chamber, the trigger of the flash lamps on a fast $K^{+}\left({\pi }^{-}\right)$ did not bias the polarization measurements. We find that the ${\Sigma }^{+}$ polarizations from the two reactions have opposite signs but similar magnitudes and are in much better agreement with the predictions of weak exchange degeneracy than previous lower-energy comparisons.

We present differential cross sections at 6 GeV/c for the baryon-exchange reactions (1) $\overline{p}p\to {\pi }^{+}{\pi }^{-}$ and (2) ${\pi }^{-}p\to p{\pi }^{-}$ over the range $-t_{min}<-t<\mathrm{}1.5\mathrm{}$ Ge${\mathrm{V}}^2$. Unlike previous experiments at similar momenta, our results are consistent with line-reversal symmetry for $-t<\mathrm{}1.0\mathrm{}$ Ge${\mathrm{V}}^2$. We contrast this to our previous results on (3) $\overline{p}p\to {\pi }^{-}{\pi }^{+}$ and (4) ${\pi }^{+}p\to p{\pi }^{+}$ for which line-reversal symmetry is not satisfied.

We have measured the ratio of inclusive production of $\eta$ to ${\pi }^0$ at transverse momenta above 1.5 GeV/c. Results are presented for various meson and proton beams with momenta of 100, 200, and 300 GeV/c incident upon a hydrogen target. The $\frac{\eta }{{\pi }^0}$ production ratio is found to be independent of incident beam momentum and of the transverse and longitudinal momenta of production. The ratio for pion- and proton-induced reactions is 0.44 ± 0.05; for kaons, it is 0.74 ± 0.12.

It is shown that in the strong-coupling limit the spectrum of quantum chromodynamics consists of closed and open strings with quarks at the ends. A Hamiltonian formulation in the axial gauge ${A_3}^a=0\mathrm{}$ is used. The theory is reformulated in terms of new canonical variables. Algebraic methods are employed to arrive at these results.

We estimate the cross section for Higgs-boson production in proton-proton collisions. We find that most of the cross section comes from a two-gluon annihilation process, in which the gluons couple to Higgs bosons via heavy-quark loops.

It is shown that energy spectra of preequilibrium $\alpha$-particle emission in ${}_{}{}^{209}{}_{}{}^{}\mathrm{Bi}$+${}_{}{}^{14}{}_{}{}^{}\mathrm{N}$ reactions are reproduced well by the statistical formula of Ericson when nuclear temperature is treated as a parameter depending on the emission angle. The resultant temperature shows monotonical decrease with increasing angles, indicating the cooling-down process of the associated composite system.

The $Z$ dependence of the orbital angular momentum transferred into the intrinsic spins of deep-inelastic collision partners is studied. The correlation between energy loss and nucleon transfer calculated by the present method is compared with that derived by previously proposed empirical methods. The currently used empirical approaches appear to be subject to serious systematic errors.

The addition of an imaginary $\overrightarrow{\mathrm{L}}·\overrightarrow{\mathrm{S}}$ interaction to the deuteron-nucleus optical potential significantly improves the fit to cross-section and analyzing-power measurements for elastic scattering of 10-15-MeV deuterons from medium-weight nuclei. The largest improvement results from a shift of the analyzing powers toward smaller angles, relative to the cross section. The imaginary $\overrightarrow{\mathrm{L}}·\overrightarrow{\mathrm{S}}$ potential has the same sign and about one-half the strength of the real $\overrightarrow{\mathrm{L}}·\overrightarrow{\mathrm{S}}$ potential.

A description of the (${\pi }^{+}, p$) reaction is presented on the assumption that the elastic scattering and reactions due to the (3,3) resonance proceed throught the $\Delta$-hole states. The multiple scattering of the pion due to the $p_{33}$ part is described by the interacting $\Delta$-hole propagation and the multiple-scattering effects due to other partial waves are taken into account in the distorted-wave Born-approximation treatment. The formalism is applied to the reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}({\pi }^{+}, p){}_{}{}^{11}{}_{}{}^{}\mathrm{C}_{\mathrm{g}.\mathrm{s}.\mathrm{}}^{}{}_{}{}^{}$.

The model of heavy-ion collisions based on the excitation of damped surface modes has been used to study the fusion reactions of Ca+Ca. The calculated fusion cross section is in good agreement with recent data, and gives support to the conclusion that the decrease in the cross section below the geometrical limit for higher energies is due to dynamical difficulties in forming a compound nucleus at intermediate or small impact parameters.

Alpha-particle energy and angular distributions have been measured for the reaction ${}_{}{}^{60}{}_{}{}^{}\mathrm{Ni}(e, \alpha )e^{\prime }X$ using electrons of energies 33, 60, and 120 MeV. Statistical-model calculations give good quantitative agreement in the region of the peak of the $\alpha$ energy spectra. Higher-energy $\alpha$ particles exhibit a forward-peaked angular distribution and a cross section several orders of magnitude above the statistical-model predictions, indicating the presence of a direct-reaction component.

Measurements of heat transport through horizontal layers of fluid heated from below are reported for three aspect ratios $\Gamma (\Gamma =\frac{D}{2d}, D=\mathrm{diameter}, d=\mathrm{height}\mathrm{of}\mathrm{the}\mathrm{cylindrical}\mathrm{cells})$.They show that for $\Gamma =57\mathrm{}$ the fluid flow is turbulent, in the sense that it has an a nonperiodic time dependence, for numbers $R>\mathrm{}{R}_t$ with $R_t\cong R_c \left(R_c\right)$ is the critical $R$ for onset of fluid flow). For $\Gamma =4.72\mathrm{}$, we find $R_t\cong 2R_c$. For $\Gamma =2.08\mathrm{}$, a quasiperiodic state exists for $R_p<~R<~R_t$, with $R_p\cong 10R_c$ and $R_t\cong 11R_c$.

Doppler-broadening measurements have been made on the 511-keV photons resulting from positron annihilation in annealed and plastically deformed samples of indium, zinc, cadmium, and gold. Over the temperature range 4-400 K, distinctive features are observed in each case. Studies with a single crystal of cadmium associate the features with defects at grain boundaries.

The $K$-edge photoabsorption spectra of the $4d$ metals calculated by the linear augmented-plane-wave method yield good agreement with the measured data. The prominent systematic features of the spectra, most easily discussed in terms of the $l=1\mathrm{}$ projected density of final states, are simply related to the underlying band structure. The results for Zr, Mo, Pd, and Ag are presented here.

The susceptibility of oxygen adsorbed on graphite indicates that magnetic transitions are present even in films of submonolayer thickness. This result contrasts with previous work on amorphous oxygen films and strongly supports the supposition that antiferromagnetic order can only be present simultaneously with configurational order.