A variational principle for meson states in constituent quark models

We present a variational principle for meson states in constituent quark models. For structureless mesons, the variational masses are expressed in terms of condensates of the theory. The method is illustrated for the pion mass in a simple Nambu-Jona-Lasinio type model, where it gives results comparable to those from the Bethe-Salpeter equation, and superior to those of the corresponding Rayleigh-Ritz ansatz.