Quark-antiquark bound states in the relativistic spectator formalism -: art. no. 035208

The original model of <q(q)over bar >-bound states, developed by Gross and Milana, which uses the relativistic spectator (Gross) equations to give a manifestly covariant description of confinement in Minkowski space that is consistent with chiral symmetry, is improved and extended. These improvements include (i) derivation of the normalization condition for the relativistic wave functions, (ii) proof that confinement automatically prohibits decays by implying the vanishing of the vertex function when both quarks are on shell, (iii) extension of the model to the strange quark sector and to sectors with unequal quark masses, (iv) removal of unphysical singularities associated with the confining interaction, and (v) inclusion of a realistic one-gluon-exchange interaction. We use phenomenological quark mass functions to build chiral symmetry into the theory and to explain the connection between the current quark and constituent quark masses. We obtain reasonable results for pions and kaons, establishing that the formalism, designed to work well in the heavy quark sectors, can also be extended to the light quark sector.