Solving Bethe-Salpeter scattering state equation in Minkowski space
  We present a method to directly solving the Bethe-Salpeter equation in Minkowski space, both for bound and scattering states. It is based on a proper treatment of the singularities which appear in the kernel, propagators and Bethe-Salpeter amplitude itself. The off-mass shell scattering amplitude for spinless particles interacting by a one boson exchange is computed for the first time. 
J. Carbonell and V.A. Karmanov
hep-ph hep-th nucl-th