Relativistic naive quark model for spinning quarks in mesons

We use two-body Dirac equations (derived from Dirac's constraint mechanics and supersymmetry) to make the naive quark model fully relativistic. Our covariant equations incorporate not only relativistic kinematics but also dynamical recoil effects that generalize Breit corrections to forms that have well-defined quantum short-distance behavior. In these equations, a crude but covariant generalization of Richardson's static quark potential produces a surprisingly good one-parameter relativistic fit to the meson spectrum