Chiral-symmetry breaking and gluon condensation

With the help of the Ward-Takahashi identities associated with a specific non linear chiral transformation of the quark fields we show, in the framework of massless QCD, that in addition to scale invariance breaking gluon condensation implies dynamical chiral symmetry breaking, that is to say the appearance of a non vanishing quark condensate. Moreover the dynamically generated quark mass is directly connected to the quark and gluon condensates.