The problem of two particle bound state in null-plane quantum field theory is considered and the Bethe-Salpeter type equation is derived. It is shown that the Green functions and the Bethe-Salpeter amplitudes as well have projective properties with respect the spinorial constituents. This fact extremely simplifies considerations in frame where both particles are on the same null-plane. Corresponding quasipotential equation is obtsiaed. The expressions for the current matrix clements of composite particles are derived and it is shown that in the lowest order on perturbation theory the quasipotential approach reproduces all results on composite particle form factors that have been obtained in the framework of the “old-fashioned perturbation theory” in infinite momentum frame.
展开▼
