Ground states of the Wick - Cutkosky model using light - front dynamics

We consider the ground state in a model with scalar nucleons and a meson using the formalism of light-front dynamics. Light-front potentials for twonucleon bound states are calculated using two approaches. First, light-front time-ordered perturbation theory is used to calculate oneand two-mesonexchange potentials. These potentials give results that agree well with the ladder and ladder plus crossed box Bethe-Salpeter spectra. Secondly, approximations that incorporate non-perturbative physics are used to calculate alternative one-meson-exchange potentials. These non-perturbative potentials give better agreement with the spectra of the full non-perturbative groundstate calculation than the perturbative potentials. For lightly-bound states, all of the approaches appear to agree with each other. PACS number(s): 21.45.+v, 03.65.Ge, 03.65.Pm, 11.10.Ef Typeset using REVTEX