Calculations of eigenvalues in functional nonlinear spinor theory

Abstract A differential equation of third order for spinor potentials is proposed, that modifies the dynamics of the nonlinear spinor theory. We derive a symmetrical eigenvalue equation using functional integration techniques. This equation and a momentum symmetrized equation - a simplified form of the mass eigenvalue equation proposed by Stumpf - are applied to calculate mass eigenvalues. By a special combination of both methods it is possible to weaken the regulari-zation dipole in Heisenberg's theory and thereby produce better boson masses. Finally, the modified theory allows a self-consistent calculation of the fermion propagator