It is pointed out that one of the formulas in Nambu's work on the analyticity of perturbation expansions can be simplified, and that as a consequence, the theory can beused to study the change of analyticity of a square diagram-the simplest four-pointdiagram-upon the insertion of internal lines in a not too complicated way. For N-,- scattering, it is shown that ( i ) insertion of any single intern...
A prolate spheroidal dipole antenna embedded in a larger dielectric confocal prolate spheroid with finite conductivity is analized as a boundary value problem in electromagnetic theory; the expressions for the fields, antenna current distribution and input impedance are obtained.
The probability of radiative capture of μ-meson by nucleus and the polarization of theemitted photon in -this process is calculated by assuming a Fermi gas-model for the nucleus.The effect of virtual pions is taken into account in the calculation. The contribution of theFeynman diagram, corresponding to the emission of photon by a virtual particle is treatedthrough considerations of gauge invarian...