A phenomenological method to analyze the experimental data on inelastic nucleon form factors is discussed and applied to the recently published electron-proton scattering data. Theoretical speculations on these form factors are then confronted with the results of this analysis.

A statistical approach to dual (Veneziano) dynamics is proposed. It operates with hadrons of given temperature rather than specifying in detail all hadronic quantum numbers. Heavy-resonance production predictions of the statistical approach are found to agree with experiment.

The $\epsilon$ meson, a broad isoscalar scalar resonance, is phenomenologically incorporated into our one-boson-exchange analysis to produce a realistic model of the $N-N$ interaction involving only known mesons.

Measurements of density thresholds for an ion-cyclotron instability in a mirror-confined plasma are interpreted in terms of a boundary for Landau damping of the unstable waves. Allowing for an observed normal-mode structure, experimental threshold values are accounted for quantitatively.

The plasma resonance in films of Mg, Zn, and Cd, was measured by observing the associated peak in photoemission. For Mg, the plasmon energy of 10.21 eV and lifetime of 1.09 × ${10}^{-15\mathrm{}}$ sec agree with values obtained by energy-loss and optical techniques. For Zn and Cd the plasmon energies are 9.46 and 8.68 eV, respectively. The lifetimes of 1.14 × ${10}^{-15\mathrm{}}$ sec and 0.82 × ${10}^{-15\mathrm{}}$ sec, for Zn and Cd, respectively, are considerably larger than previously observed.

This comment on a recent Physical Review Letter by Yahia, Lee, and Fournier points out that zero resistance cannot be inferred from their observation of zero voltage without additional experiments to eliminate the possibility that the current is zero in the vicinity of the potential probes due to a combination of anisotropic magnetoconductivity and asymmetry of the current contacts.

Considerations given in the paper by Yahia, Lee, and Fournier showing the inappropriateness of the explanations of Marcus and Reed for the observations in gallium are taken up once again in detail in this paper.

Experimental results have been obtained which reveal that tunneling through the body diagonal is important for ${\mathrm{Li}}^{+}$ in KCl. Two possible structures for the potential well which can account for this behavior are inferred.

The temperature dependence of the electron-scattering rate in Cu has been investigated in the range 2 to 20°K with magnetic-field-induced surface quantum states. From the temperature dependence we obtain the electron-phonon scattering rate at points on the Cu Fermi surface. Over the limited range of our present explorations we observe a scattering-rate anisotropy of nearly a factor of 6, the highest scattering rate being on the necks.

In this Letter some of the disagreement between previous NMR investigations of transition-metal impurities in Fe is clarified. A clear analysis of the experimental data is presented and its relation to the average unpaired spin density in several Fe alloys as measured by neutron scattering is pointed out.

Starting from the kinetic equations obeyed by the time-dependent spin-correlation functions, we have calculated the homogeneous function which appears in the dynamical scaling expression for the linewidth of critical fluctuations in ferromagnets and antiferromagnets. In agreement with recent experimental findings, this function shows a minimum for $\frac{\kappa }{q}\equiv \mathrm{inverse}$ correlation $\mathrm{l}\mathrm{e}\mathrm{n}\mathrm{g}\mathrm{t}\mathrm{h}/\mathrm{w}\mathrm{a}\mathrm{v}\mathrm{e}\mathrm{n}\mathrm{u}\mathrm{m}\mathrm{b}\mathrm{e}\mathrm{r}\ne 0$.

Fully variational unrestricted Hartree-Fock calculations for the ${\left(\mathrm{M}\mathrm{n}{\mathrm{F}}_6\right)}^{4-}$ cluster are reported. Charge and spin densities are analyzed and shown to result in a neutron magnetic form factor which is contracted relative to the free-ion value in agreement with experiment but contrary to predictions of simple covalent-bonding theory.

Emphasis is placed on the temperature dependence of the magnetic resistance $R_{\mathrm{mag}}$ in the region ${10}^{-4\mathrm{}}\lesssim \left|\epsilon \right|\lesssim {10}^{-2\mathrm{}}$, where $\epsilon =\frac{(T-T_c)}{T_c}$. The temperature dependence of $\frac{d{R}_{\mathrm{mag}}}{\mathrm{dT}}$ is found to be the same, within experimental error, as that of the specific heat, both above and below $T_c$. The anomalous behavior in the region $0\lesssim \epsilon \lesssim 5\times {10}^{-3\mathrm{}}$ reported by Craig, Goldburg, Kitchens, and Budnick is not observed.

The helicity of antineutrinos emitted in nuclear transitions has been measured by determining the circular polarization of gamma rays emitted by a gaseous source of ${\mathrm{Hg}}^{203}$ and resonantly scattered by ${\mathrm{Tl}}^{203}$ nuclei. The antineutrinos and electrons preceding these gamma rays are known to travel approximately opposite to the gamma quanta. The helicity of neutrinos emitted following electron capture has been remeasured using the same apparatus.

Secondary particles produced by muon-nucleon interactions at 10.1 GeV/c (positive) and 14.6 GeV/c (negative muons) have been identified in nuclear emulsions. The energy spectrum and angular distribution (in c.m. system) is given for pion, kaon, and proton along with their partial cross sections. Yang's hypothesis of limiting fragmentation in high-energy lepton-hadron collision is compared with our results which tend to support it.

The inelastic scattering of muons has been measured using 10.1-GeV/c positive and 14.6-GeV/c negative muons in nuclear emulsion. The partial and integral cross sections have been measured for both beams along with the energy dependence of their total cross sections. Experimental values are compared with the theory by using three different forms, i.e., first, second, and fourth power of $\frac{{m_{\rho }}^2}{({m_{\rho }}^2+q^2)}$ for ${\sigma }_{\mathrm{exptl}}(q^2, \nu )$, the quantity commonly called the "virtual photon-nucleon total cross section."

We have studied the neutral decays of ${\eta }^0$ mesons produced in a hydrogen bubble chamber. Utilizing the conversion within the chamber of one photon from each decay, we obtain the following percentages of the neutral decays: $\frac{({\eta }^0\to \gamma \gamma )}{({\eta }^0\to \mathrm{neutrals})}=(48.6\mathrm{}\pm 3.6)\%$, $\frac{({\eta }^0\to {\pi }^0\gamma \gamma )}{({\eta }^0\to \mathrm{neutrals})}=\left({12.2}_{-4.4\mathrm{}}^{+5.2\mathrm{}}\right)\%$, and $\frac{({\eta }^0\to 3{\pi }^0)}{({\eta }^0\to \mathrm{neutrals})=(39.2\mathrm{}\pm 4.2)\%}$.%. With the assumption of no ${\pi }^0\gamma \gamma$ contribution, we obtain the ratio $\frac{({\eta }^0\to 3{\pi }^0)}{({\eta }^0\to \gamma \gamma )}=0.91\mathrm{}\pm 0.14$.

The existence of the $\left(\overline{e}{\nu }_e\right)\left({\overline{\nu }}_{e}e\right)$ weak interaction is confirmed by the results of nine astrophysical tests. The value of the coupling constant is equal to, or close to, the coupling constant of beta decay, namely $g^2={10}^{0+2}{g_{\beta }}^2$.

The hard-pion effective-range formula for the pion form factor of Brehm, Golowich, and Prasad is derived from unitarity and (vector) meson dominance assuming a real tree form factor as input. The result is generalized and applied to the $\pi -A_1-\rho$ system. The suitably continued finite $\rho$-width form factors are used to calculate the soft ${\pi }^{+}-{\pi }^0$ mass difference when (a) both tree form factors are unsubtracted in broken chiral symmetry ($\delta m\simeq 5.7$ MeV) and when (b) both tree form factors are subtracted ($\delta =-\frac{1}{2}$) ($\delta m\simeq 5.2$ MeV).

We present an electromagnetic interaction Hamiltonian for an arbitrary $N$-particle system with any mass, charge, spin, and magnetic moment which is consistent with the low-energy theorem for Compton scattering and the Drell-Hearn-Gerasimov sum rule to order ${\mathrm{}\left(\mathrm{mass}\right)\mathrm{}}^{-2\mathrm{}}$. It is related to the sum of individual Foldy-Wouthuysen interactions by a unitary transformation.