Excitation functions of the reaction ${}_{}{}^{10}{}_{}{}^{}\mathrm{B}({}_{}{}^{14}{}_{}{}^{}\mathrm{N}, \alpha ){}_{}{}^{20}{}_{}{}^{}\mathrm{Ne}$ near the Coulomb barrier reveal clearly correlated cross-section structure in different $\alpha$-particle channels. This indicates intermediate structure which had never been observed in the interaction of two nonidentical, odd-odd nuclei at such high level densities.

The analog ($p$, ${}_{}{}^3{}_{}{}^{}\mathrm{He}$) and ($p, t$) reactions on ${}_{}{}^{16}{}_{}{}^{}\mathrm{O}$ have been studied by a second-order distorted-wave Born-approximation (DWBA) theory. Nucleon transfer is assumed to occur here only one nucleon at a time. The contribution of the isospin-1 intermediate-state projectile was made small at forward angles by increasing the imaginary part of the corresponding optical potential. This increase can be associated with the preferential decay of an isospin-1 projectile. Convergence of the DWBA is studied by comparing one- and two-step calculations.

I discuss the photon antibunching effect and point out that there exist many states which exhibit the effect and demonstrate a simple procedure for generating them mathematically. I also suggest here a possible approach to the experimental observation of the effect.

The cross section for the photoproduction of ${\pi }^0$ mesons from complex nuclei at small angles has been measured at incident bremsstrahlung energies of 4.4 and 6.6 GeV. The data are fitted by a cross section calculated from a sum of Primakoff and nuclear-production amplitudes. A total decay width for the ${\pi }^0$ meson of 8.02±0.42 eV is obtained from the magnitude of the Primakoff amplitude.

We report the observation of a heavy particle $J$, with mass $m=3.1\mathrm{}$ GeV and width approximately zero. The observation was made from the reaction $p+\mathrm{Be}\to e^{+}+e^{-}+x$ by measuring the $e^{+}{e}^{-}$ mass spectrum with a precise pair spectrometer at the Brookhaven National Laboratory's 30-GeV alternating-gradient synchrotron.

We have observed a very sharp peak in the cross section for $e^{+}{e}^{-}\to \mathrm{hadrons}, e^{+}{e}^{-}$, and possibly ${\mu }^{+}{\mu }^{-}$ at a center-of-mass energy of 3.105±0.003 GeV. The upper limit to the full width at half-maximum is 1.3 MeV.

We report on the results at ADONE to study the properties of the newly found 3.1-BeV particle.

A time-of-flight method is used to measure the distribution in speed and angle of the metastable atoms produced when ground-state helium atoms are excited by electron impact at near-threshold energies. The results are compared to predictions based on both theoretical and experimental determinations of the differential cross section, and it appears that there are significant discrepancies between the time-of-flight data and the predictions based on available theoretical cross-section calculations.

Energy-loss measurements in transmission experiments on carbon and gold foils with ∼ 100-keV/nucleon ${\mathrm{H}}_2^{+}$ and ${\mathrm{H}}_3^{+}$ beams reveal that protons moving in spatially correlated clusters have effective charge numbers significantly larger than unity. The theory traces the origin of this effect to the coherent dynamic response of the target electrons due to the vicinage of particles in tight clusters and, in linear response approximation, predicts quantitatively the observed enhanced energy loss of proton clusters.

We have found a new instability that is driven by a radial gradient of the electron temperature or by the electron drift in the "unfavorable" curvature of the magnetic field lines for high-temperature confined plasmas in which a fraction of the electron population is magnetically trapped. The relevant mode is standing along the magnetic field, is symmetric about the point of minimum field, and has relatively short wavelengths across the magnetic field.

The surface state near the top of the valence bands on the cleaved (111) face of Si has been investigated by using angular-resolved photoemission spectroscopy at the photon energy 10.2 eV. Anisotropy, dispersion, and splitting are observed. The results are consistent with an appreciable admixture of $S_2$ character in this surface-state band.

The monochromatized x-ray photoemission spectra of the Pt $4f$ and Ni $2p_{\frac{3}{2}}$ levels in the pure elements exhibit an asymmetry which disappears when Pt and Ni atoms are diluted into Cd, but not when Pt is diluted into Au. From the behavior of the conduction-band photoemission spectra of these alloys it is argued that the elimination of the asymmetry is related to the reduction of the local density of states of the electrons at the Fermi level available to screen the hole potential, as suggested by recent theories.

Using nonlocal pseudopotentials for silicon and germanium we are able to calculate the temperature dependence of the forbidden (222) reflection and we find it to be in excellent agreement with experiment. The accuracy of the pseudocharge density for the case of silicon is also examined and found to be in good agreement with recent x-ray experimental results.

The (${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^8{}_{}{}^{}\mathrm{B}$), (${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{11}{}_{}{}^{}\mathrm{C}$), and (${}_{}{}^{11}{}_{}{}^{}\mathrm{B}$, ${}_{}{}^{13}{}_{}{}^{}\mathrm{N}$) reactions were studied at 86 MeV as a technique for the mass measurement and spectroscopy of exotic nuclei.

Two decoupled rotational bands in ${}_{}{}^{165}{}_{}{}^{}\mathrm{Yb}$ are observed in (heavy ion, $\mathrm{xn}$) experiments. The $i_{\frac{13}{2}}$ band does not backbend, whereas the $h_{\frac{9}{2}}$ band does. This provides strong evidence that only $i_{\frac{13}{2}}$ neutrons contribute to backbending in this region.

The correct asymptotic behavior of the wave function deduced from the Faddeev equations for three-particle scattering is used to determine the asymptotic conditions. With these conditions, the equivalent set of partial differential equations in configuration space has a unique solution and is numerically solved for two examples. Comparison is made with results from two other basically different methods.

A relatively bias-free comparison is made of inclusive and semi-inclusive charged-pion single-particle spectra in ${\pi }^{+}p$ and $\mathrm{pp}$ interactions. Inclusive Mueller factorization is satisfied by ${\pi }^{-}$ but not ${\pi }^{+}$ production. Factorization holds for proton-target fragmentation into ${\pi }^{-}$ for a fixed number of ${\pi }^{-}$ backward in the c.m. system, but not for fixed total multiplicity. In the central region, ${\pi }^{+}p\to {\pi }^{\pm }$ shows an $s^{-\frac{1}{4}}$ approach to the same value, ∼ 0.78, seen in other reactions.

The electronic transition dipole moment was determined for the transition $X{}_{}{}^1{}_{}{}^{}{\Sigma }_{\mathrm{g}}_{}^{+}{}_{}{}^{}\leftarrow B{}_{}{}^1{}_{}{}^{}\Pi _{\mathrm{u}}^{}{}_{}{}^{}$ of ${\mathrm{Na}}_2$ and was found to be $6.8+0.5\mathcal{r}$ D over a range of internuclear distance $\mathcal{r}$ of 2.6-5.0 Å. Our results agree with earlier lifetime measurements and are in qualitative agreement with semiquantitative theoretical calculations, but they strongly disagree with the recent work of Callender, Gersten, Leigh, and Yang.

We show that the Doppler shift can provide velocity resolution in excited-state molecular-collision experiments which is comparable to that obtainable in molecular-beam machines. In addition, the state of the quasimolecule formed in the collision can be selected.

Nonequilibrium populations of proton spin-symmetry species of methyl groups undergoing tunneling rotation occur in a sample which has been thermally quenched to helium temperatures. When the external magnetic field is adjusted to bring the Larmor frequency of impurity electrons into coincidence with the methyl-group tunneling frequency, cross relaxation releases the stored mechanical energy of tunneling rotation to heat the sample.