Scalar mesons as simple quark+antiquark states

The Nijmegen Unitarized Meson Model and its application to scalar mesons is briefly revisited. It is shown that all scalar states up to 1.5 GeV can be described as triplet-P-zero quark+antiquark states coupled to the OZI-allowed open and closed two-meson channels consisting of pseudoscalar and vector mesons. Crucial are the manifestation of a resonance-doubling phenomenon, typical for strong S-wave decay, and the employment of truly flavor-symmetric coupling constants. Also S-wave meson-meson scattering is thus reasonably well described, without any parameter fit.