Trace anomaly and chiral symmetry breaking scale in the Nambu and Jona-Lasinio model

The possible connection between the chiral symmetry breaking scale in the Nambu and Jona-Lasinio model and gluonic degrees of freedom is studied by introducing the dilatation (gluonium) field. Identifying the divergence of the dilatation current with the QCD trace anomaly, the empirical value of the gluon condensate gives a constituent quark mass of about 400 MeV. We study the glueball-meson effective Lagrangian and discuss scalar modes as a mixture of glueball and qq states.