We present results of a superconducting magnetic levitation experiment which provide evidence for the existence of fractional charge on matter. Three niobium balls heat-treated on a tungsten substrate were found to have residual charges of $(+0.337\mathrm{}\pm 0.009)e$, $(-0.001\mathrm{}\pm 0.025)e$, and $(-0.331\mathrm{}\pm 0.070)e$. All five niobium balls heat-treated on a niobium substrate had residual charges near zero.

Almost all of the single-particle strength of the neutron-hole state $1{h_{\frac{11}{2}}}^{-1\mathrm{}}$ in ${}_{}{}^{145,147}{}_{}{}^{}\mathrm{Nd}$ and ${}_{}{}^{147,149,151,153}{}_{}{}^{}\mathrm{Sm}$ has been observed by using the preferential population to the high-spin states of the (${}_{}{}^3{}_{}{}^{}\mathrm{He}$, $\alpha$) reaction at 82 MeV. The strength distribution in the $\alpha$-particle spectra suggests that the $1{h_{\frac{11}{2}}}^{-1\mathrm{}}$ state in these nuclei is split into the Nilsson orbitals as a result of deformation. The deformation parameters obtained are consistent with those of the adjacent even-even nuclei, except in the $N=85\mathrm{}$ isotones.

We report first measurements of the velocity dependence of an alkali-rare-gas fine-structure-state-changing collision with adequate range and resolution to reveal a peak in the cross section. The method uses crossed atomic beams and selective laser excitation. Results are presented for Na colliding with Ne, Ar, and Kr. The results for Na-Ar are in good agreement with theory, while those for Na-Ne and Na-Kr are in serious disagreement.

The resonant interaction between an rf electric field and a coherent atomic state is studied by monitoring the field-induced changes in the quantum beats after a beam-foil collision. A theory for the interaction is discussed and a preliminary measurement of the fine-structure interval $J=\frac{3}{2}$ to $J=\frac{5}{2}$ in the $n=4\mathrm{}$ state of hydrogen is presented.

The first measurement of polarized x-rays from a laser-produced plasma is reported. The degree of polarization is related to the net anisotropy of the hot-electron velocity distribution.

A molecular beam of ${\mathrm{H}}_2$ and ${\mathrm{D}}_2$ was used to investigate the angular dependence of the reaction probability for ${\mathrm{H}}_2$-${\mathrm{D}}_2$ exchange (${\mathrm{H}}_2$+${\mathrm{D}}_2$→2HD) on the Pt(111) and $\mathrm{Pt}\mathrm{}\left(s\right)\mathrm{}$-[6(111)× (111)] surfaces. On the stepped surface, a marked increase in the production of HD is observed when the beam of reactants strikes the open side of the step structure. The Pt(111) surface exhibits a smooth decrease in HD production from normal incidence to grazing angles.

We present strong evidence that the first gradient correction to the local density approximation for exchange and correlation is inappropriate near physical metallic surfaces, in that it fails to improve the energy and worsens the density profile. Further evidence is presented for the validity of the wave-vector analysis procedure, in that it is shown to be correct both for slowly varying and for rapidly varying density profiles.

The angular dependence of uv- (21.2-eV photon energy) induced photoemission from single-crystal PbS has been investigated. The dependence of the positions of observed peaks on ${\overrightarrow{\mathrm{k}}}_{\parallel }$ is compared with the prediction of band-structure calculations. Nearly perfect agreement between theory and experiment is found by assuming that only peaks in the appropriate one-dimensional density of initial states calculated along lines of fixed ${\overrightarrow{\mathrm{k}}}_{\parallel }$ contribute to the observed spectra.

Exact solutions of similarity type are obtained for Boltzmann equations describing the temporal relaxation to equilibrium of an $N$-component gas with elastic collision cross sections of special form.

An exactly solvable model of the crystal-vacuum interface is constructed which exhibits a roughening transition. The model is obtained as a special limit of a ferromagnetic Ising model and it is isomorphic to the symmetric six-vertex model. Some of the thermodynamic properties of the system are discussed.

Inclusive spectra are presented for ${\pi }^{\pm }$ production in 100-GeV/c$\overline{p}p$ interactions. The rapidity distribution for the difference ($\overline{p}p-pp$) approximately scales as the difference in total cross sections in the fragmentation region between 12 and 100 GeV/c and exhibits an approximate $s^{-\frac{1}{2}}$dependence in the central region.

I argue that in a gauge theory of absolute quark confinement two-body amplitudes of mesons are nonvanishing only on an equal-time plane in the rest frame of mesons. The vector dominance model of electromagnetic form factors follows as a consequence. The parton model for inelastic processes would remain valid.

We have obtained 68±9 events of the previously unseen radiative decay ${\eta }^{\prime }\to \omega \gamma$ ($\omega \to {\pi }^{+}{\pi }^{-}{\pi }^0$, ${\pi }^0\to \gamma \gamma$) in a charged- and neutral-particle spectrometer. Simultaneously, 1505 events of the decay ${\eta }^{\prime }\to \eta {\pi }^{+}{\pi }^{-}$ ($\eta \to \gamma \gamma$) were collected in the same apparatus, allowing a direct measurement of this branching ratio. We find $\frac{({\eta }^{\prime }\to \omega \gamma )}{({\eta }^{\prime }\to \eta {\pi }^{+}{\pi }^{-})}=(6.8\mathrm{}\pm 1.3)\%$ and use published data to derive $\frac{({\eta }^{\prime }\to \rho \gamma )}{({\eta }^{\prime }\to \omega \gamma )}=9.9\mathrm{}\pm 2.0$, in excellent agreement with predictions based on vector meson dominance.

We calculate the weak decay constant of paracharmonium (${\eta }_c$) using a linear potential model. The result is somewhat larger than, but of the order of, $F_{\pi }$ and depends on the universal Regge slope ${\alpha }^{\prime }$. A number of amusing features are noted.

We analyze muon and electron lepton-number nonconservation in a pure $V-A$ gauge model. The rates for $\mu \to e\gamma$, $\mu \to \mathrm{ee}\overline{e}$, and $K_L\to \mu \overline{e}$ are computed for this model. We find that for a reasonable range of neutral heavy-lepton mass these rates are in accord with, but not extremely small compared to, present experimental bounds. We comment on the nonorthogonality of ${\nu }_e$ and ${\nu }_{\mu }$, and interesting features of the $L^{-}$ decays.

The energy dependence of the total cross section for the mutual inelastic scattering reaction ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ → ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$($2_1^{+}$) + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$($2_1^{+}$) has been measured from $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}\left({}_{}{}^{12}{}_{}{}^{}\mathrm{C}\right)=15\mathrm{} \mathrm{to} 45$ MeV. A rotationlike sequence of resonances is observed with strengths up to 17% of the unitarity limit and widths approaching the ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ + ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ single-particle width.

The elastic scattering of ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ + ${}_{}{}^{28}{}_{}{}^{}\mathrm{Si}$ at $E_{\mathrm{c}.\mathrm{m}.\mathrm{}}=35\mathrm{}$ MeV has been measured in the angular range $20°<~{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}<~180°$. The data exhibit a strongly oscillatory behavior in the region $60°<{\theta }_{\mathrm{c}.\mathrm{m}.\mathrm{}}<~180°$ and a pronounced backward rise up to $\frac{d\sigma }{d{\sigma }_{\mathrm{Ruth}}}\left(180\mathrm{}°\right)\approx 1.5\times {10}^{-2\mathrm{}}$. The structure at backward angles is of the form of a Legendre polynomial ${\left|P_{l=26\mathrm{}}\right(cos\theta \left)\right|}^2$, indicating the existence of a partial-wave (orbiting) resonance.

We investigated the excitation of nuclei by longitudinally polarized electrons in view of parity mixtures of nuclear states. The asymmetry in the cross section for the left- and right-polarized electrons is shown to be already very large at low momentum transfer. In many cases the asymmetries caused by parity mixtures are larger by orders of magnitude compared to the contributions expected from weak $Z^0$-boson exchange.

Production of various nuclei following bombardment of medium-mass nuclei with intermediate-energy protons is determined by observing both prompt and delayed $\gamma$ rays. The variation of production cross section with target mass and with bombarding energy over the range 80 to 160 MeV implies that between one and two nucleons are emitted in the pre-equilibrium phase of the interaction.

We have measured the muonic x-ray intensity patterns of C in ${\left(\mathrm{C}{\mathrm{H}}_2\right)}_x$ and ${\left(\mathrm{C}{\mathrm{D}}_2\right)}_x$ and of O in ${\mathrm{H}}_2$O and ${\mathrm{D}}_2$O. In both cases the relative intensities of the higher Lyman series members are significantly lower in the deuterium compounds, indicating that the initial angular momentum distribution of the muons captured on C and O is weighted to higher $l$ states compared to the normal hydrogen compounds. This isotope effect has not been predicted by any model of negative-meson capture.