Exploration of a physical picture for the QCD scalar channel

Understand

A generalized linear sigma model is employed to study the quark structure of low lying scalar as well as pseudoscalar states.

• The model allows the possible mixing of quark anti-quark states with others made of two quarks and two antiquarks but no a priori assumption is made about the quark contents of the predicted physical states.
• Effects of SU(3) symmetry breaking are included.
• The lighter conventional pseudoscalars turn out to be primarily of two quark type whereas the lighter scalars have very large four quark admixtures.