Two-body Dirac equation and its WFO

A relativistic equation is proposed for the bound state of two particles, which is in accord with the boundary condition for the propagation of the negative-energy states and reduces to the (one-body)Dirac equation in the infinite limit of one of the constituent masses. It also has the symmetries to assure the existence of the anti-bound-state with the same mass. The interaction kernel is systematically constructed by diagonalizing the Hamiltonian of the background field theory. Its wave function at the origin (WFO) behaves properly in a manner sugested by the covariant field theory