Global aspects of the scalar meson puzzle

Understand

A generalized linear sigma model for low energy QCD is employed to study the quark structure of eight low lying scalar isomultiplets as well as eight low lying pseudoscalar isomultiplets.

• The model, building on earlier work, assumes the possible mixing of quark anti-quark states with others made of two quarks and two antiquarks.
• No {\it a priori} assumption is made about the quark contents of the states, which emerge as predictions.
• An amusing and contrasting pattern for the quark structure is found; the lighter conventional pseudoscalars are, as expected, primarily of two quark type whereas the lighter scalars have very large four quark admixtures.