Scalar Mesons in the Unitarized Quark Model

Abstract

It is shown that in spite of their unconventional experimental properties the scalar mesons $\epsilon$, $\delta$, $\kappa$, and $S^{*}$ can be understood as the unitarized remnants of conventional $q\overline{q}$ states. The $S^{*}$ and $\delta$ have large components of $q\overline{q}q\overline{q}$ in the form of virtual two-meson states (mainly $K\overline{K}$).