  We briefly review theoretical calculations for the pseudoscalar-vector meson
hyperfine splitting with no open flavor and also report a many body field
theoretical effort to assess the impact of chiral symmetry in the choice of
effective potentials for relativistic quark models. Our calculations predict
the missing eta_b meson to have mass near 9400 $MeV$. The radial excitation
$\eta_c(2S)$ is in agreement with the measurements of the BELLE and most
recently BABAR collaborations.
