Deviations from the ideal mixing

It is intended to show that both quark components and hadron components of resonances have their own roles in the hadron spectroscopy, by investigating various meson multiplets. Before going into the calculation, the experimental status is explained. The deviation from the ideal mixing occurs through multi-hadron channels. The phi-omega mixing occurs via the loop diagrams, which contribute to the self-energy of resonances. They are calculated with the unitarity (the imaginary part) and the dispersion integral (the real part). The scheme discussed here takes into account the threshold effects properly, and gives good prediction for some low mass mesons. On the other hand, it is not so economical for high mass resonances, in which lots of self-energy diagrams compete. (Kato, T.)