What Happened with the $f_0(500)/\sigma $ Meson? Theory and Experiment
R. Kamiński · Acta Physica Polonica B Proceedings Supplement · 2015
Once upon a time, the picture of hadrons was of mesons made of a quark and an antiquark, and baryons of three quarks.Though hadrons heavier than the ground states inevitably decay by the strong interaction, the successes of the quark model might suggest their decays are a mere perturbation.However, Eef van Beveren, whose career we celebrate here, recognised that decays are an integral part of the life of a hadron.The channels into which they decay are often essential to their very existence.These hold the secrets of strong coupling QCD and teach us the way quarks really build hadrons.