Low-temperature triplet-exciton interaction, yielding delayed blue fluorescence, exhibits large magnetic field quenching. The observed effect differs, however, from that anticipated assuming thermalization and simple spin conservation. The quenching is concentration dependent, indicating that the magnetic field decreases exciton interaction probability.

Both a giant resistance peak and a small conductance peak have been observed in a single tunnel junction. The conductance peak splits into two peaks in a magnetic field indicating that it is similar to the conductance peaks seen previously.

Measurements of current fluctuations and critical currents as a function of temperature have been made in a ring of superconducting tin with a current resolution corresponding to about 0.1 quanta of magnetic flux in the cylinder and a temperature resolution of a few microdegrees. The fluctuations occur between neighboring quantum states at a rate which increases rapidly with increasing temperature. The critical currents do not follow the temperature dependence predicted by theory.

A general expansion of the two-center exchange integral is used in enumerating the many situations for which antisymmetric exchange occurs. We show that the antisymmetric exchange found in the Coulomb interaction between ions in Kramers' doublet states occurs under much more general conditions than previously considered.

Levels of even Sn isotopes ($A=108-118\mathrm{}$) have been studied in $\mathrm{Cd}(\alpha , xn)$ reactions. Nanosecond time analysis of $\gamma$ rays has revealed the systematic presence of isomers.

A local, central, density-dependent potential is derived from a given two-nucleon tensor force in nuclear matter. Such an effective force can be used in finite-nuclei calculations in place of the tensor force to determine the gross properties of nuclei.

In a nuclear-emulsion experiment to determine the lifetime of ${}_{\Lambda }{}^{}{}_{}{}^{}\mathrm{H}_{}^3{}_{}{}^{}$ we find a value consistent with that of the free $\Lambda$ hyperon as predicted by theory, and not in good agreement with a previous measurement.

A particle-unstable hydrogen isotope of mass 4 is formed in the reaction ${\pi }^{-}+{\mathrm{Li}}^7\to {\mathrm{H}}^3+{\mathrm{H}}^4$. Two discrete levels of ${\mathrm{H}}^4$ have been found and their binding energies and widths have been determined. Some evidence for the existence of a third level is presented.

For certain nuclear species, it is possible to use the studies of muonic x-ray transitions to investigate nuclear Coulomb monopole transition matrix elements. The case of $0^{+}$ -$0^{+}$ vibrational excitation is treated in detail as an example.

Absolute values for triton polarizations have been measured for the first time. We suggest an analyzer for polarized tritons with energies of 7 MeV and higher. A scattered beam of 10-MeV tritons with a polarization of 88% from a cross section of greater than 600 mb/sr is reported.

While "ordinary" Regge trajectories can be bootstrapped using the resonance approximation to finite-energy sum rules, we suggest that the Pomeranchuk trajectory is mostly built from the nonresonating background at low energies. This hypothesis (a) explains the constancy of $\mathrm{KN}$ and $\mathrm{NN}$ total cross-sections (in contrast to $\overline{K}N$ and $\overline{N}N$ over a wide energy range; (b) predicts many other interesting relations which are experimentally satisfied; and (c) leads to no obvious inconsistencies.

Electromagnetic mass shifts, equal-time commutators (ETC), and their relation are analyzed, using the Jost-Lehmann representation for the forward Compton amplitude. The divergences in $\delta m$ are determined by Lorentz scalars associated with the ETC (when these exist). These results are illustrated by models with currents bilinear and linear in canonical fields. Existence of the ETC implies that the Jost-Lehmann representation is unsubtracted.

It is shown that any model in which the scattering amplitude is given by finitely spaced trajectories of direct-channel resonances does not yield Regge asymptotic behavior in the direct channel. Several difficulties associated with the use of Regge asymptotic behavior at low values of the energy through the finite-energy sum rules are noted.

Making use of a recent result obtained by Jackiw in the context of the renormalization group we examine the question of whether there exists the possibility of obtaining finite charge renormalization by means of an eigenvalue condition on the bare coupling constant. It is shown that to sixth order in $e_0$ a cancellation of the divergences encountered in perturbation theory cannot occur.

From the decay distribution and the polarization of the $\omega$ in $B\to \omega \pi$, the $B$ is found to have either $J^P=1^{+}$ or $J^P=2^{+}{3}^{-}{4}^{+}\cdots$. The observed polarization of the $B$ appears more plausible for the $J^P=1^{+}$ hypothesis.

We have observed the $g$ meson in ${\pi }^{+}{\pi }^{-}$, ${\pi }^{-}{\pi }^0$, and ${\pi }^{-}{\pi }^{-}{\pi }^{+}{\pi }^0$ mass spectra and have measured masses, widths, and some branching ratios. The angular distributions and total cross sections presented strongly indicate a $J^P$ of $3^{-}$ for the $g$ meson.

The equation which must be used to obtain the Debye-Waller factor $f^{\prime }$ from Mössbauer absorption measurements on single-crystal samples with resolved and hence generally polarized lines is given. The polarization terms for a crystal having the symmetry of siderite are explicitly presented and theoretical area ratios are compared with recently reported values calculated from a theory neglecting polarization. New experimental data indicate that $f^{\prime }>~0.6$ for all directions in siderite.