Pion number and correlator mixing

We discuss the manifestations of chiral symmetry restoration in the form of correlator mixing. We establish a link between the energy integrated mixing cross-sections and the pion scalar density which governs the quenching factors of coupling constants, such as the pion decay one, as well as the quark condensate evolution. We interpret the excess of low mass lepton pairs seen in heavy ion collisions as a correlator mixing effect, i.e. a manifestation of chiral symmetry restoration.