An indefinite metric and perturbation theory. II

The present paper is a refinement and elaboration of the ideas of [1] on the applicability of Feynman procedure in the nonlinear spinor theory of elementary particles. The possibilities of probabilistic interpretation in a scheme with an indefinite metric and of constructing a unitary physical scattering matrix are analyzed. The modified perturbation theory proposed in [1] is used to compute meson masses and meson-nucleon coupling constants. The results turn out to be physically satisfactory.The author is grateful to Prof. D. Ivanenko.for his interest and useful comments, to Dr. V. Ya. Fainberg for valuable remarks, and to L. Dadashev for stimulating criticisms.