Nuclear resonance effects in mesonic atoms result from near degeneracy of nuclear excitation and atomic de-excitation energies. The $E2\mathrm{}$ nuclear resonance effect was observed in pionic cadmium by comparing selected pionic x-ray intensity ratios from ${}_{}{}^{112}{}_{}{}^{}\mathrm{Cd}$ with those from ${}_{}{}^{111}{}_{}{}^{}\mathrm{Cd}$. The effect for hadronic atoms is now unambiguously established and the results are in close agreement with the theoretical predictions.

We have observed the $1S-2S$ transition in atomic hydrogen and deuterium by Doppler-free two-photon spectroscopy, using a frequency-doubled pulsed dye laser at 2430 Å. Simultaneous recording of the absorption spectrum of the Balmer-$\beta$ line at 4860 Å, using the fundamental dye-laser output, allowed us to precisely compare the energy intervals $1S-2S$ and $2S$, $P-4S$, $P$, $D$ and to determine the Lamb shift of the $1S$ ground state to be 8.3 ± 0.3 GHz (D) and 8.6 ± 0.8 GHz (H).

Transit-time magnetic pumping (TTMP) in stellarators has been attempted experimentally with the result that enhanced plasma pump-out occurs. This pump-out may be explained by conversion of trapped particles to circulating particles by TTMP outside of the separatrix. This occurs for trapped particles because the bounce frequency is of the order of the TTMP driving frequency.

The frequency spectrum and the angular distribution of the scattered light and the absorption coefficient due to stimulated Raman scattering are obtained by extensive numerical simulations of one- and two-dimensional plane plasma targets irradiated normally or obliquely by high-power laser light. Theoretical models are given to explain the numerical results.

The reflection of phonons at an interface between a silicon crystal and solidified hydrogen and deuterium has been investigated by the heat-pulse method. The reflection coefficients are found to be much smaller than predicted by the acoustic-mismatch theory.

Measurement of spin polarization of photoelectrons from F${\mathrm{e}}_3$${\mathrm{O}}_4$ (MAG) and ${\mathrm{Li}}_{0.5}$${\mathrm{Fe}}_{2.5}$${\mathrm{O}}_4$ (LIF) up to $\hslash \omega =11\mathrm{}$ eV shows that $B$-site $3d$ levels are higher in energy than $A$-site $3d$ levels. In MAG, unpolarized $2p$ electrons are not emitted up to 11 eV. Existing energy diagrams of MAG do not agree fully with the results. As a direct consequence of Hund's rule, the polarization spectra of MAG and LIF are very different because of the presence of ${\mathrm{Fe}}^{2+}$ in MAG.

Resistivity and Hall effect measurements have been made on ${\mathrm{Sm}}_{1-x}{\mathrm{Y}}_x\mathrm{S}$ alloys which exhibit black to gold phase transitions as a function of temperature and composition, similar to SmS under pressure. The results indicate that in the gold phase there is a virtual bound state at the Fermi level which causes additional scattering and suppresses the Hall effect. In the black phase, the virtual bound state is below the Fermi level and does not contribute to the Hall effect.

An isomeric state in ${}_{}{}^{52}{}_{}{}^{}\mathrm{Fe}$ has been located at $E_x=6.83\mathrm{}\pm 0.25$ MeV with the reaction ${}_{}{}^{40}{}_{}{}^{}\mathrm{Ca}({}_{}{}^{14}{}_{}{}^{}\mathrm{N}, pn){}_{}{}^{52}{}_{}{}^{}\mathrm{Fe}$. The state decays by positron emission to the (${11}^{+}$) 3.837-MeV state of ${}_{}{}^{52}{}_{}{}^{}\mathrm{Mn}$ with $T_{\frac{1}{2}}=56\mathrm{}\pm 8$ sec. The probable spin and parity of the isomer is ${12}^{+}$.

In bombardments of Au with 25-GeV ${}_{}{}^{12}{}_{}{}^{}\mathrm{C}$ ions we have studied the energy and angular distribution of fragments with $5<~Z<~9$ emitted at energies up to ∼ 1000 MeV. Beyond ∼ 150 MeV the spectra change from roughly exponential in energy and isotropic in some forward-moving frame to roughly inverse power law in energy (steepening with increasing $Z$) and strongly forward peaked in direction. Possible bumps in the angular and energy distributions suggest hydrodynamic effects.

The proton-helium elastic scattering data at 1 GeV are analyzed using the effective-channel approach. The calculated spin-averaged cross section is in good agreement with the experiment from Saclay up to 35 deg, effectively with no free adjustable parameters. An estimate for the average excitation energy and for the ratio $\frac{\mathrm{Re}f}{\mathrm{Im}f}$ of the nucleon amplitude is obtained.

Measurements were made to detect differences in the velocity of propagation of $\gamma$ rays and electrons in the energy range 15-20 GeV, by using a time-of-flight technique with 1-psec sensitivity and a flight path of ∼ 1 km. A relative velocity difference larger than $1-{\beta }_e$ (∼ 5× ${10}^{-10\mathrm{}}$) would imply a breakdown of special relativity. No significant difference in the velocities of light and electrons was observed to within ∼ 2 parts in ${10}^7$.

We have calculated the static monopole contributions to the ${\left(Z\alpha \right)}^2{\alpha }^2$ vacuum polarization correction for the $4f_{\frac{5}{2}}$ state in muonic Pb. We find an energy shift of -1 ± 0.1 eV (increased binding). We argue that neglected higher multipole contributions have the same sign and similarly small magnitude, thus increasing by a slight amount the current discrepancy between muonic atom theory and experiment.

A part of the hitherto neglected radiative corrections of order ${\alpha }^2$ is calculated. Its inclusion in the analysis virtually eliminates all the discrepancies between the measured and the calculated energies of the $5g-4f$ transitions in muonic atoms of heavy nuclei.

If, in collisions of hadrons, the newly discovered $J^0$ particle turns out to be produced in association with its antiparticle ${\overline{J}}^0$ with conservation of an additive quantum number, then the decays of the $J^0-{\overline{J}}^0$ systems produced in hadron collisions and in $e^{+}{e}^{-}$ colliding beams provide new possibilities for studying the nature and the strength of $\mathrm{CP}$-invariance-violating interactions.

The 3105-MeV narrow resonance discovered at Brookhaven National Laboratory and Stanford Linear Accelerator Center is analyzed. A new type of interaction is suggested to account for its decay properties and production cross section.

The expectation value of electrical charge in charged vacuum is calculated utilizing the Thomas-Fermi model. We find almost complete screening of the nuclear charge. For any given nuclear density there is an upper bound for the electrical potential. For normal nuclear densities this value is - 250 MeV. This suggests that the vacuum is stable against spontaneous formation of heavy, charged particles.

I consider a six-quark model for hadrons. The three new ones possess charges +, 0, -, and an additional quantum number $g$ (for "gentleness"). To explain the recently observed resonances, a selection rule is proposed: Electromagnetism violates $g$ spin and the photon is blind to gentleness. Experimental tests for the idea are discussed.

A generalization of the non-Abelian gauge theory of Yang and Mills is presented in which the field strengths ${F_{\mu \nu }}^i$ and their duals ${{\tilde{F}}_{\mu \nu }}^i$ enter symmetrically. The theory is symmetrical under a noncompact gauge group and permits the introduction of both electric and magnetic sources.

The possibility is raised that the new meson resonances are of weak origin and measurements are proposed which can clarify this issue. Experimental situations are found where the forward-backward asymmetry is sizable. Theoretical expectations for the longitudinal polarization of the muon and decay modes of the resonances are discussed.

We propose a new fundamental interaction of an "effective" strength which is comparable with that of the electromagnetic interaction. This interaction is mediated by a triplet of neutral gauge bosons. The lower limit of the gauge boson mass is estimated to be ∼ 4 GeV. Qualitative analysis of the decay modes of the recently discovered 3.1- and 3.7- GeV-mass particles and several consequences of the medium interaction are given.